Let's summarize: what to check for error P0504
Summarizing all the possible reasons that caused failure 0504, you can create an approximate checklist that you need to follow to find the cause and reset the error:
- Adjusting the gap between the pedal and the limit switch rod.
- Checking fuse F23 (in some cases the fuse number may not match).
- Checking and replacing brake light bulbs.
- Checking and cleaning the contacts in the rear light, on the end of the brake pedal and further along the circuit.
- Checking or replacing the on-board computer, flashing the ECU.
Cleaning and repair, replacement of the brake pedal sensor (limit switch). We check the return of the rod and the stiffness of the spring. Catalog number of the pedal end switch - 2118-3720010.
Malfunction of the lights themselves
If during the check from the fuse box to the limit switch no problems are found, then you should move on. Now you should test the wiring from the second limit switch connector to the stop connectors with a tester. If it is working, then you need to check the board. The printed circuit board on which the taillights are mounted is not ideal, and is one of the biggest problems of all VAZ cars.
Its tracks often burn out or peel off, causing the lights to stop working. This problem can be solved in two ways - either re-solder the tracks (which can be done with a regular soldering iron, although not in road conditions) or replace the board with a new one (most motorists choose the second option).
Another reason why the VAZ 2114 brake lights do not work may be oxidation of the lamp sockets. In order to eliminate this problem, it is enough to clean all contacts from oxides that have appeared on them.
This is best done in one of the following ways:
- small grit sandpaper;
- WD-40 solution;
- kerosene;
- purified gasoline (“galosh”).
You should absolutely not use gasoline or other solvents to clean contacts.
The last option for faulty stops is the light bulbs themselves. It makes no sense to give any detailed advice here - you just need to replace the burnt out light bulbs with new ones.
By following all the tips listed above, the car enthusiast gets the opportunity to check the entire electrical circuit of the brake lights, starting from the fuse box and ending with the bulbs in the lamps. Thanks to this, the guarantee that the fault will be accurately detected and eliminated is 100%.
Brake pedal sensor for Lada Granta
What is a brake pedal sensor, what problems can arise with it and how to fix them yourself. You will learn about all this below.
The introduction of updated standards regarding the level of toxicity of exhaust emissions from vehicles into the atmospheric air has created conditions for the development of new engine control devices by the Volzhsky Automobile Plant.
In addition, a brake pedal sensor appeared on Lada cars, including Grants. But many car owners, after using their car for a very short time, begin to notice error P0504, signaling a breakdown of this element. Let's try to understand this issue in more detail.
What car owners say about the clutch pedal sensor
- What is a clutch pedal sensor used for?
“I have a car with a two-liter engine, I bought it not so long ago. The cruise control did not turn on, and on a cold engine there were jumps in speed when changing gears, the car jerked, and there was increased fuel consumption. After replacing the sensor, the machine works fine, like new. The whole point was that the faulty mechanism affected the operation of the car at idle speed.”
“I had such an experience. After removal, when I pressed the clutch, the revolutions dropped longer, and when the speed was turned on there were jolts. However, the car does not push much. After disconnecting the device, the car began to accelerate faster, for me this is a plus.”
“Are you planning to disassemble the sensor? Heat its body to increase the plasticity of the material. It is attached quite tightly, you will need a friend to help you, you are unlikely to be able to do it with two hands. Parts should be opened carefully. There is a spring installed inside, it can jump out and get lost. Be careful, otherwise the contacts will also fall out. I repeat once again, the parts should be opened with extreme caution.”
Causes of sensor malfunction and their symptoms
In most cases, the above error occurs because the sensor (frog) has not been adjusted properly. It is for this reason that the car owner notes the emergence of such problems as:
- instability of the engine: it starts poorly or stalls immediately;
- instability of speed.
The sensor combines two functions: it is both an element of the brake pedal position and a brake light switch. Most often, the malfunction is caused by the sensor misalignment already mentioned above, or by a broken spring. The problem that has arisen manifests itself by the “check” icon lighting up and error P0504 (implying a mismatch in the operation of this part).
So, we found out that error P0504 on Grants is caused by:
- malfunction of the part itself or its wiring;
- the element has not been adjusted properly;
- The ECM may need to be reprogrammed.
If problems occur, you can repair the sensor yourself by changing the spring, or change the element itself.
How to adjust the brake light switch on LADA cars
On LADA cars, depending on the model and year of manufacture, AVTOVAZ used different brake light sensors (brake pedal position sensor or “frog”). During operation of the vehicle or when removing/installing the sensor, it must be adjusted. Do you know how to adjust this sensor yourself?
Carrying out pre-installation diagnostics
Before purchasing and installing a new sensor to replace a broken one, it is recommended to diagnose the old sensor and, if there is a breakdown, fix it yourself. There are two nuts on the sensor body, the first of which is located at the bottom, and the second at the top. The nut located at the top should adjust the clearance of the part (sometimes it is set incorrectly). This leads to disruption of the normal functioning of the button, therefore, you will need to set the gap so that there are no obstacles to its normal movement.
After the adjustment, the ECU error is reset, then you need to start the engine and wait about fifteen minutes, since errors are not recorded immediately. If error 0504 is not marked, it means that the cause of the engine malfunction was an incorrect sensor setting. If it appears again, you will need to replace this element with a new one.
Diagnostics
Before buying a new sensor, it is necessary to diagnose the DPT. It happens that the sensor nuts are unscrewed due to vibration and thereby its adjustment is disrupted, which can result in an error on the dashboard.
Check sequence:
- Press the brake pedal by hand and release, make sure that the sensor stop returns to its original position, thereby confirming that the return mechanism spring is working.
- Check the adjustment and tightening of the locknuts; with the brake pedal free, there should be a distance of no more than 0.5-1 mm from the sensor stop to the housing.
If any of these points are not met, you need to start replacing and adjusting the brake pedal sensor on the Lada Granta.
Carrying out work on dismantling and repairing the sensor
In most cases, repairing a sensor does not take a significant amount of time and does not require the car owner to have either specific knowledge or the use of complex tools. You can do it yourself without going to a repair shop.
First you need to disconnect the negative terminal from the battery, and then move to the driver’s seat in the car. Move the front seats back as far as possible and remove the interior carpet. The sensor is located next to the brake pedal; to remove it, you will need to disconnect the clamp and the block with wires from its connector.
Carefully loosen the fastening nut and carefully unscrew the body of the part, then disassemble it. This element is a two-piece element, and both parts are held in place with latches.
There is a spring in the inside of the sensor, which is often what causes problems. Replacing a faulty spring with a new one, having the same number of turns and suitable dimensions, most often helps to eliminate the problem.
Having completed the repair, reassemble the element by performing the manipulations you performed to disassemble it in the opposite sequence, and then install it in its original place, and if necessary, adjust it. The part is tightened until the brake pedal goes down, after which it is turned 90 degrees clockwise and secured with a lock nut. As a result, with the brake pedal lowered, the switch rod will be in a recessed position, and when you press it, it will go beyond the boundaries of the switch body.
Next, start the engine and wait at least ten minutes; if the error does not appear, you have correctly identified the cause of the problem. If error P0504 appears again, adjust the sensor; if this error continues to appear, the part will need to be replaced.
auto electrician
Code P0504 Brake pedal A/B switches, signal mismatch
Code P0504 is entered if: - the signals of the brake pedal limit switches “14/23” are mismatched for more than 200 seconds with the engine running in idle mode; - or the number of presses on the brake pedal, determined by the signals of two limit switches “14/23”, differs by the value of the diagnostic threshold on a moving vehicle.
The malfunction indicator lights up on the 3rd trip after a permanent malfunction occurs. Description of checks
1 Checks whether code P0504 is active at the time of the request. 2 Electrical circuits are being checked. 3 Adjust the brake pedal switch gap. Diagnostic Information - The scan tool is in 1 Parameters mode; 1 General View" shows the status bit B_BREMS of contacts "23" of the brake pedal switch. — Monitor the state of contacts “14” using the brake light lamps. If a discrepancy between the signals of the “14/23” switches is detected, the engine control system will operate in emergency mode until the end of the current trip.
1 If the brake lights do not light up periodically or constantly when you press the brake pedal, check: — whether the brake pedal switch rod is jammed when you press the brake pedal; — check the presence of on-board voltage on contacts “1” and “4” of the brake pedal switch in the free and pressed state in accordance with the operating principle of the switch; — check the serviceability of the corresponding brake light circuit fuses; — check the condition and reliability of the connection of the contacts in the brake pedal switch block. 2 If, when you press the brake pedal with the side lights, direction indicators, reverse lights, and fog lights on, a faint glow of the brake lights is observed, check the reliability of the ground circuit of the rear lights. 3 Check the presence of on-board voltage on contacts “2” and “3” of the brake pedal switch in the free and pressed state in accordance with the operating principle of the switch.
Brake light wiring diagram for Lada Granta and Kalina 2
stop signal position
The brake light switch is part of the brake pedal assembly and is designed to send appropriate signals to the ECM when the driver presses/releases the brake pedal. In throttle-by-wire (E-throttle) systems, the brake pedal switch signals play an important role because they are used by the safety function of the ECM software. For this reason, it is very important to ensure that the brake light switch is always in working order. In the event of a discrepancy between its functional switching characteristics, for example, when spontaneously changing the adjustment values specified in the instructions (due to vibrations of the brake pedal, wear of the switch and pedal block), the car’s engine may go into emergency mode with forcibly reduced power. The size of the adjustment gap of the switch should be within 0.2...0.5 mm. The brake light switch has two groups of contacts, the first of which switches voltage from Cl. 15, and the second is voltage with Cl. 30, supplied to the brake light lamp. Both of these signals are sent to the ECM. When the brake pedal is released, the contacts of the first group should be normally closed, and the contacts of the second group should be normally open. If the brake light switch malfunctions, the controller stores its code in its memory and turns on the warning light. A fault code is also entered if the gap between the drive pusher attachment and the switch body is incorrectly adjusted
Related pages:
- Error P0504 Lada Priora, Kalina, 4x4 - ME17.9.7 /…
- Error P0830 Lada Priora, Kalina, 4x4 - ME17.9.7 /…
- Error P0830 Lada Granta, Kalina 2, clutch switch
- Error P1388 Lada Granta, Kalina 2 - electronic pedal
- Error P1388 Lada Vesta
- Error P1338 Lada Priora, Kalina, 4x4 - ME17.9.7 /…
Carrying out an inspection
To carry out the procedure for checking the brake pedal sensor on a Grant, you will need to turn on the ignition, and then press the brake pedal, while paying attention to the brake lights - have they come on? Then you need to release the pedal, again focusing your attention on the brake lights, which should now go out. If the brake lights do not light up, you should check the sensor itself, and also see if voltage is supplied from the battery to the wiring harness block.
When performing the test, circuit 1-4 should be in the closed position, and circuit 2-3 should be in the open position. Then press the rod, normally circuit 2-3 should close and circuit 1-4 should open.
How to check
Turn on the ignition and press the brake pedal, the brake lights should light up. After releasing the pedal they should go out. If the lamps do not light up, check the brake pedal sensor and the voltage supply from the battery to the wiring harness block.
(Largus, Vesta, XRAY) Move the rod lock to the right position using a screwdriver. We check the brake pedal sensor using a multimeter in ohmmeter mode. Circuit 3-4 should be closed (resistance value is close to zero), and circuit 1-2 should be open (resistance should tend to infinity). After pressing the rod, circuit 3-4 should open, and circuit 1-2 should close. Before installation, move the rod to the left position.
(Priora, Kalina, Granta, Niva 4x4) Circuit 1-4 should be closed, and circuit 2-3 should be open. After pressing the rod, circuit 2-3 will close, and circuit 1-4 will open.
Hi all. Today we'll talk about the brake pedal sensor, or brake pedal position sensor to be precise. You will learn about the weak points of this device, as well as how to repair the brake pedal sensor or replace it on a Lada Granta.
Adjusting the grant brake pedal sensor
We will show you how to remove and replace the brake pedal sensor in a Lada Granta car. Carry out diagnostics for error P0504. It is located under the brake pedal, near the steering column. In order to remove the sensor, it is necessary to disconnect the wire block. In the picture you see two antennae on the sides:
You need to press them and pull out the block with wires. Next, use a 19mm wrench, unscrew the locknut a little, then tighten it by hand. You can install a new sensor or diagnose and repair the old one. For convenience, its contacts are indicated by numbers. When it is in the free position, contacts 1 and 4 should be open, and contacts 2 and 3 should be closed. When we press the button, everything will be the other way around, contacts 1 and 4 will be closed, and 2 and 3 will be open. If this does not happen, then our button is faulty.
Installation occurs in the reverse order, adjust so that the pedal presses the button and releases it with a small stroke.
Video of removing and replacing the brake pedal sensor in Lada Granta, error P0504:
Backup video on how to remove and replace the brake pedal sensor in Lada Granta (error P0504):
If error P0504 indicates a malfunction of the brake pedal sensor, a check will light up on the panel; you can remove it using the on-board computer, which many Granta owners have installed, or simply disconnect the terminal from the battery for 20 seconds.
Problems that can arise with the brake pedal sensor in the Lada Granta have long ceased to be classified as news. It is this unpleasant circumstance that becomes the main reason for the appearance of error code “P0504”. This sensor can cause a lot of inconvenience to the owner, and mileage does not have any effect on its performance.
The price of the issue is equal to the amount of 180 rubles. for a new part. Why is a fee charged, and not a free replacement with the fact of repair indicated in the service book? The waiting period for spare parts to arrive is more than 4 days, since they are never in stock.
The annoying frequency of the “Check” symbol lighting up prompts the owner to go to a service center or make adjustments himself by tightening the corresponding bolts. This procedure aims to reduce the force of contact between the button and the pedal surface. If you “dig deeper,” then you can hardly get by with just one adjustment action, since the most common occurrence of error P0504 occurs when parking with the automatic transmission lever activated in position “D.”
The obvious symptom factor can be identified with the moment when the Lada Granta does not want to start from the key fob. As a temporary solution, you can apply short-term pressure on the brake pedal. The car will start, but error P0504 does not disappear from the ECU memory.
If such “inadequate” operation of the sensor occurs, then this jeopardizes the safety of machine operation. Many owners have noted the fact that the BC freezes, as a result of which the car begins to twitch or may even stall in the middle of traffic, and error P0504 is shown.
Lada Priora Hatchback Strict SE Logbook Error P0504 Brake pedal sensor and its solution
Good evening everyone, nothing interesting happened to the car, and then bam, today it means I’m not touching anyone’s food, I didn’t pay attention to how often I pressed the brake, but suddenly the car begins to slow down to such an extent that it seems that it stalls while driving and then but after 1.5 seconds it starts, I couldn’t believe my eyes, at first I thought the gear was knocked out, when I press the gas at 40 km/h it just doesn’t go, so + besides, there are no revolutions at all! In a panic, I went and refueled (it was 5L at that time), I thought it was petrol, I refueled, I gave it a ***, I accelerated, like normal, I parked the car near the house, I started it an hour later, an error pops up, fortunately I have a friend Lyo with a cable and a program in next door, I rush to him. We do the diagnostics, and here’s the most interesting part:
Having read on the Internet that either the sensor is faulty ****, or the stoppers may burn out and because of this it is tripping, but the stoppers are all burning, the previous ones are intact. Someone also wrote that the sensor may be poorly adjusted, and it works too often when the brake is pressed. They cleared the error, now I’m driving and looking, so far everything is fine, so far there is no desire to change the sensor.
Today I went and bought a sensor, it costs 232 rubles, a little expensive IMHO) I installed it, it’s very easy to install, I unscrewed the nut and unscrewed the sensor itself, before of course disconnecting it from the power supply (which, by the way, only enters the sensor on one side, that is, by mistake you won't be able to connect it).
New, purchased
Old on the left, new on the right
The last photo shows that the spring of the old sensor has apparently stretched, because the limit switch no longer snaps off properly, but only moves halfway. I reassembled everything in the reverse order, adjusted it by eye
Then I cleared the error, and now everything is quiet, thank you all for your attention) And for those who will ever do this for the first time, there is no need to remove anything, I moved the seat all the way back, raised the steering wheel as high as possible, pulled out the rug (so as not to get dirty), took off the cover that covers the fuses (to let in more light) and lay right under the steering wheel, and everything is clearly visible there. I used the key for 19. The replacement took 10 minutes maximum
It became interesting, I disassembled the old sensor, everything is visible as is) The upper spring simply broke
All the best.
What are the reasons that cause sensor failure?
A detailed examination of the essence of the problem that arose, when error code 0504 appeared, will allow us to determine the list of reasons. This refers to the disassembly of the ill-fated sensor in the LADA Granta car. Three clips serve as an obstacle to this noble procedure, preventing the component from being easily disassembled. After overcoming this “barrier”, it becomes possible to observe the real reasons that caused the breakdown:
- deformation of the smaller (of 2) springs located on the rod;
- different heights of the contacts of the designated sensor;
- poor material (steel) used for the manufacture of terminals;
- presence of play on the floating contact element.
“Ringing” can be used as the initial stage of diagnosis. Each of the contacts must be subjected to this action separately, and then in pairs (“2nd” with “3rd”). The experience of LADA Granta owners indicates the presence of a dull tone during ringing, which confirms the malfunction of the contact group. Serviceable contacts are characterized by a distinct ringing “squeak”.
The operation of the brake pedal sensor is based on the following technology:
- the rod is located inside the element and presses the floating contact (when the pedal is released) to the upper group;
- the rod is again inside, but the pressure is applied to the lower group (corresponds to the depressed position of the pedal).
This principle is not complicated, but this does not improve the performance of the sensor. The main problem lies in the bent state of the floating contact. This kind of defect can occur due to this contact getting caught on the spring element, which provokes the sensor to send a signal to the LADA Granta on-board controller about the allegedly activated brake, which is why error code 0504 occurs.
How to replace the sensor?
If you have received error code 0504, to perform this simple procedure you will need to provide access to the pedal bracket on the Lada Granta, on which our “ill-fated” sensor is actually present, or rather, above the pedal assembly. A well-carried out replacement will guarantee long-term operation.
- Remove the negative terminal from the battery terminal.
- We press out the plastic retainer (use a screwdriver).
- Next, remove the block with wires.
- Turn the sensor in a clockwise direction.
- We remove the faulty part.
We install the new component on a Lada Granta car in the reverse order. Don’t forget to first release the pedal to be able to insert the new product into its socket. We turn the component against the direction of the arrow until the corresponding click appears.
Removal and replacement
- We remove the “negative” mark from the battery, this is necessary to ensure safety during work, since the work is carried out on the electrical part of the car.
- Next, in the cabin, move the driver's seat back all the way and remove the mat. We find the sensor under the steering column, press the connector latch and remove it.
- We install the new sensor in the reverse order with the correct adjustment (0.5-1mm between the stop and the sensor body).
About alternative sensor options
Since domestic “devices” for the Lada Granta car are not able to prevent an unpleasant situation, it is possible to use other devices that act as analogues. Such a component could be a brake light switch from Volkswagen, or more precisely: “FACET 7.1126”. This switch is slightly more expensive than the “native” one (560 rubles) and has the following features:
- four contacts;
- threaded leg with a similar diameter of 12 mm.
To successfully install the indicated analogue, you will need to acquire an adapter for the terminals.
Car : Lada Granta. Asks : Evgeniy Denisov. The essence of the question : Lada Granta is getting error p0504?
Hello, please tell me what could be the cause of the malfunction on my Lada Granta: the check light periodically lights up, on the on-board computer and during diagnostics using ELM 327 it was possible to establish error code p0504, what does this mean and how to fix it?
p0504 - problems with the brake pedal sensor
Error code p0504 , according to the manufacturer's manual, indicates the presence of a malfunction or other problem with the brake pedal sensor .
Usually, such errors always occur when the sensor itself, or rather the contacts located inside, simply fail.
Reasons for the error
And all this is facilitated by certain reasons that have already been identified by leading AvtoVAZ specialists:
- Short circuit in the network of brake lights and side lights caused by improper installation of the lamps.
- Use of lamps that do not meet the requirements.
The idea of the whole design is that instead of a regular brake light switch, a double one is installed. The first circuit of which is designed to operate when the brake pedal is pressed, the second when the brake pedal is released. When you press the pedal, the signal goes not only to the brake lights, but also to the controller itself, and when released, only to one controller. Therefore, when these factors are combined during operation, the controller suspects that not everything is in order with the “STOP” lamps, and issues a similar error.
Before addressing the above problem, you should check that all rear lighting fixtures are properly and securely installed to match the type and design of each lighting element.
What to do if the sensor is not on sale?
But what to do if this spare part is not for sale in the outback? It happens. Then you need to remove the sensor and disassemble it. The contacts may be burnt, this is a disease of this sensor!
How to change the clutch sensor on a Priora
Well, the widespread computerization of cars has reached such a unit as the clutch. No, the electronic unit does not yet control the process itself, but it already controls this process. To do this, a sensor is installed under the clutch pedal to monitor the progress of the clutch.
Operating principle of the electronic engine control system (ECM)
In a modern car, all process control, except for the rotation of the steering wheel, and even then, is entrusted to the computer, or Electronic Control Unit (ECU). It contains a program with many different tables.
In general, the ECU receives data about the state of the car, speed, revolutions, and activated mechanisms from a large number of sensors.
Based on the results of these observations, the ECU, using these tables, includes certain ignition modes, fuel supply and other executive functions.
The role of the clutch sensor
It would seem, what does the clutch have to do with it? And here's what it has to do with it. When the clutch engages, the most sensible thing to do is to reduce the engine speed. But not to idle, but according to the speed of the car. This is not always available to the driver, especially a beginner. And here the computer will come to the rescue. Reacting to the signal from the clutch sensor, it can independently adjust the engine speed.
Important! In addition, in accordance with the Priora speed sensor, the ECU can obtain information about the serviceability of the clutch. https://www.youtube.com/embed/cqgcTyUkMqg
Summarizing the above, we can say that the presence of a sensor on the clutch allows:
- saves fuel;
- make driving easier;
- monitor the serviceability of the coupling;
- increase its service life.
Therefore, its serviceability is an important factor in the Priora control system.
Design and location of the Priora clutch sensor
In principle, this is the simplest switch. In the position when the clutch is disengaged and the pedal is not pressed, the sensor circuit is open. If you press the clutch drive, the limit switch of the sensor closes and the signal “clutch is on” is sent to the ECU.
It is located on the clutch pedal mounting assembly, where the very tip of this pedal is located opposite the sensor end switch.
Symptoms of this part being faulty
Since this element is connected to the ECU, it reacts to its failure first of all. That is, it gives peculiar signals that are reflected on the instrument panel and are noticeable in the behavior of the Priora when driving.
- turning on the “Check Anger” light;
- twitching when starting to move;
- a sharp drop or, conversely, an increase in speed when the clutch is engaged.
There can be three malfunctions in total: a breakdown of the sensor itself, a break or short circuit in its circuit, and incorrect adjustment of the position of the limit switch on the pedal.
Attention! Only Prioras, which have an electronic throttle, are equipped with such a device. Cars with a regular throttle cable do not have one.
It is also available for all-wheel drive VAZ. It must be remembered that these are two types of sensors, and they are not interchangeable!
In general, the “Check” warning lamp lights up in cases where the ECU has not received a signal within 2 seconds when starting from a stop or during four shifts on the move without a signal. Accordingly, the signs mentioned above appear.
And only after that remove it. This is a simple procedure. The clutch sensor is attached with only two self-tapping bolts, and it is not difficult to remove it with a short, shaped screwdriver. Well, then, on the spot, decide whether to start going to retail outlets in search of a new unit, or try to restore the old part. Well, put it in its place.
After finishing work on the Priora, do not forget to reset the ECU error memory.
conclusions
If you often experience this error, then the brake pedal sensor is to blame. You should get a new element in the store (or contact an official dealer, since this malfunction is a warranty case if the car’s warranty has not yet expired), since on the automotive goods market this spare part costs about 200 rubles. And install it in a certified service center, an official dealer, or if you have a certain skill, you can perform the operations yourself.
What to do if the Lada Granta has error 0504
Lada Granta car owners often begin to panic when they encounter error 0504 in the background of a glowing Check Engine light. This malfunction can lead to other malfunctions in the engine, when the latter does not start, periodically stalls, and the speed also fluctuates. Often the cause may be the brake pedal position sensor (frog). The brake light sensor and brake light switch are equipped in one housing. As a rule, the cause of the problem is damage to the spring. In this situation, it is time to repair the sensor on your own by replacing the spring with a new one. In addition, you can install a new sensor.
- Error P0504: what is it?
- Error pop-up P0504: factors
- Adjusting the brake pedal sensor in Grant
- Broken brake pedal sensor
- Wiring and light bulbs are common factors in code 0504.
- Summarizing
Possible problems and their causes
In most cases, the above error occurs because the product is not properly adjusted. As a result, the following problems may appear over time: - incorrect operation of the engine; — “floating” speed; - the car engine does not start or stalls.
From a design point of view, the sensor is combined with the brake light switch in one housing. Often the cause of product malfunction is its incorrect adjustment or spring failure.
Error P0504: what is it?
This type of error is associated exclusively with the brake pedal, in particular its sensor. Calling it the latter may not be entirely correct, because it is presented in the form of an end switch with 2 contacts. A simple mechanism with a spring-loaded contact pad sends voltage to the lamps for turning on the brake pedal sensor.
At the same time, on the Lada Granta, which has an automatic transmission and an electric gas pedal, the protocols of this switch are taken into account when calculating the transmission performance pattern. That is, when the contacts of the limit switch are closed, a signal from the electrical control unit is sent to the throttle valve. The latter tends to hinder engine power. Brake lights, in turn, can light up, but they can also not function even with working bulbs.
About the sensor
The DPT is a conventional “frog with two contacts” for making and breaking. There are no complex electrical circuits in its device.
One of the contacts, which works to close, when you press the brake pedal, lights up the brake lights, which in turn signal the cars behind to brake.
The second contact, which opens when the brake pedal is pressed, opens its contacts and thereby sends a signal to the ECU to remove the load from the engine. This is necessary to reduce the fuel supply during the braking period, that is, when driving at high speeds (above idle) and when you press the brake pedal, the car begins to stop, and at this time the sensor sends a signal to the ECU to reduce the fuel supply through the injectors to reduce the speed and emissions of exhaust gases into the atmosphere.
The sensor is located on the pedal assembly under the steering column of the car; it is mounted on a plate with two nuts; they also carry out adjustment and control tightening.
The cost of a sensor in an auto parts store is up to 300 rubles.
Error pop-up P0504: factors
A code for incorrect notification of the brake pedal switches can be seen in situations involving an unadjusted limit switch. So, after flashing the M74, M74.9.7 ECU, engineers made some changes to the operation of the engine control. This results in a reduction in the number of harmful emissions. As practice shows, adjustments in the firmware only strangled the engine, thereby causing a lot of problems regarding sensors and limit switches.
Note. In the domestic car Lada Granta, one body is equipped with a brake pedal position sensor and a limit switch, a stop lamp switch. The first factor in the occurrence of problem P0504 is the incorrect adjustment of the sensor housing.
Adjusting the brake pedal sensor in Grant
The sensor is attached to the bracket with 2 nuts screwed onto a plastic housing. Thus, the upper nut fixes the position of the sensor according to the pedal. The nominal space between the pedal and the heel of the sensor is 2-3 mm when the pedal is released.
Meanwhile, if there is no gap, the sensor is able to give a signal at the slightest touch of the pedal, which actually leads to the P0504 code lighting up, as well as the activation of the Check Engine warning light. In turn, after a basic adjustment of the gap using 2 keys, you need to start the car and look for errors. The value of P0504 will not be reset instantly, however, if the problem is still in the adjustment, therefore, the error code will disappear after 10-15 minutes with the engine turned on without load. If such measures do not produce results, it is worth looking for a reason elsewhere.
Broken brake pedal sensor
One of the possible factors for error P0504 to appear in a car is a breakdown or defect of the pedal end switch itself. It is worth noting that the quality of AvtoVAZ consumables has always suffered, and this is the case now. Even Russian sensors are mostly equipped with fairly cheap springs and contacts made in China. The result is that the springs fail and the contacts usually burn out after 5-8 thousand miles.
Due to the spring, the regulator rod does not return to its original position, therefore, the system receives a notification that the brake pedal is pressed. In this situation, the ECU reads that both the brake and gas pedals are pressed together. Therefore, the throttle valve is forced to close.
In many cases, replacing the pedal adjuster on the Grant solves the problem associated with fault 0504. However, it happens that a working sensor refuses to work after installation, and then it is necessary to consider other possible causes.
Wiring and light bulbs are common factors in code 0504.
Again it is worth paying attention to the components. If the owners of the Granta did not leave reviews, it would be incorrect to blame the functioning brake lamp for a malfunction. However, this point does occur. The active spiral of the 1-pin brake light bulb stretches over time, while the antennae that hold it close with the rest. In this situation, it makes sense to install new brake lamps, which can help correct error P0504.
Possible causes of the Check Engine error and alert may be:
- burnt contacts on the limit switch;
- weak contact of the light bulb base;
- short circuit of the brake light power supply wiring.
These errors are easy to check. There is a voltage at the sensor supply wires of 0.12-0.15 V - which means you need to look for a short circuit or oxidation on the contact blocks/boards. Note that there should be no voltage on the supply wires.
Summarizing
Summarizing what has been said about the possible reasons that caused the failure and error P0504, it’s time to draw up an indicative checklist according to which you should act when searching for the cause. Once you find the problem, you can reset the error.
- Adjusting the gap in the middle of the brake pedal and limit switch rod.
- Cleaning and repair, installation of a new brake pedal sensor. To do this, you need to check the return of the rod, as well as the spring stiffness. The number of the brake pedal limit switch is 2118-3720010.
- Inspect fuse F23 (the number does not always match).
- Checking and installing sensor lamps.
- Inspect and clean the connections of the rear light, pedal end switch, and so on along the chain.
- Checking or dismantling the on-board computer, as well as flashing the electrical control unit.
