What does code U0100 mean?
Error U0100 - “loss of communication with the engine control unit ECM/PCM.”
The Engine Control Module (ECM) is the computer responsible for controlling the engine. The engine control unit interacts with other vehicle control units via a data exchange bus. This bus is called a controller area network (CAN) and allows all modules to communicate with each other.
There are two CAN buses: CAN High and CAN low. CAN High - has a high data transfer rate of 500 Kbps. CAN low - with a low data transfer rate of 125k bps. Physically it is a shielded twisted pair cable. There is a termination resistor at the end of each data channel.
The control units exchange data via the CAN bus with each other. Error code U0100 means the PCM is unable to send or receive CAN bus communication signals.
Note for error U0100
Diagnosis of error U0100 is carried out with the ignition on, the required voltage in the vehicle's on-board network and the correct configuration of other key units.
Hello everyone)) please tell me who had a problem or is having a problem with Check, error code U0100 -Lost Communication Whith ECM/PCM “A”. What is this and how to fix this problem??
DRL at night 27 LEDs
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If the car is under warranty
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How to Diagnose and Fix Error U0100
Pre-check
The prosodic occurrence of error U0100 may be caused by a low or faulty battery. Clear the error and check if the code returns. If this happens, the next step is to visually inspect the wiring. An experienced specialist can visually identify broken wires or lack of contact. If the source of the problem is found, the problem should be repaired and the error code cleared. If nothing is found, you need to check the technical service bulletins (TSBs). TSB is the vehicle manufacturer's recommended diagnostic and repair procedures. Finding the appropriate bulletin can significantly reduce diagnostic time.
Check the battery
Before you begin diagnostics, you must make sure that the battery is fully charged. For the engine control unit to function, an appropriate power source is required. Charge or replace the battery if necessary.
Check for other fault codes
If related error codes are stored for several different units, it is likely that the problem is not only with the engine control unit, but also with the CAN bus. In this case, the diagnostic will move on to checking the CAN bus. The bus must be checked for short circuits to ground and power. The integrity of the CAN bus is checked through the diagnostic port using a digital multimeter (DMM). By connecting a multimeter to the CAN High and CAN Low contacts of the diagnostic port, you can detect opens, shorts and high resistance in the CAN bus.
There are two termination resistors at each end of the CAN bus. If one of them fails, the tire will continue to operate. However, if they both fail, the bus will shut down. The integrity of resistors is checked by measuring their resistance. To do this, connect a digital multimeter to the diagnostic port (set to measure circuit resistance). A normal reading is around 60 ohms.
Check PCM
To diagnose the performance of the engine control unit, the ODB II diagnostic scanner is used. The scanner is connected to the vehicle's diagnostic port. Once connected to the car, the scanner becomes another module in the network and exchanges data over the network.
If the ECM does not respond to the scanner's actions, then it is necessary to find out the reasons. The control module (ECM) wiring must be completely inspected before claiming that the ECM is faulty. A digital multimeter (DMM) is used to check the integrity of the wiring and control unit. If an open or short circuit is detected in the circuit, the fault must be repaired. Then the problem can be fixed.
If all signs indicate a faulty ECM, then before replacing the engine control unit, it is necessary to check its software. In some cases, when updating the control unit firmware, it will work correctly. If this does not give any results, then the control unit must be replaced.
ESP error + ESP OFF in Chevrolet Captiva
One day, while driving on a road with a constant rise of 35 degrees, the ESP + ESP OFF indication came on.
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In the event of a malfunction, two ESP + ESP OFF indicators will be constantly on, the engine will be in power limit mode, the speed will not exceed 4000.
The Op-Com scanner immediately caught errors C0561 and P0101: C0561 - Incorrect signal from the Transmission Control Module (TCM)
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Error C0561 - Invalid signal from the Transmission Control Module (TCM)
P0101 - Mass/volume Air flow circuit range/Performance (mass air flow sensor error)
Interestingly, the MAF was replaced with a new one 10,000 km ago.
1. Power system:
a. Cleaning the MAF - starting from the connector and ending with the search for possible air leaks (it is on the other side of the rubber air duct relative to the throttle valve). b. Cleaning the throttle body - I couldn’t find the original source, but the recommendation is as follows - “Open the hood. You see a big black pipe. At one end of the MAF there is a throttle at the other. To remove the throttle, you disconnect the connector and the pipe from it, take an 8x10 tube and turn the 4 bolts around the perimeter, remove, then spray with carburetor cleaner until the throttle is clean. Reassemble in reverse order. Try not to touch the damper - the damper is driven by a motor, and its position is monitored by a sensor. If you move it, there will be problems with alignment. In principle, after 1-2 days of driving they go away on their own (the system adjusts itself), but it’s better not to allow this.” c. Replacing the air filter d. Very rarely - icing of the throttle valve (long-term driving on the highway at ambient temperatures below -30). Recommendation from NJM e. Air leak through the air duct; 2:3879 2. Brake system;
a. Brake fluid level b. ABS sensors (connectors can become flooded - sometimes cleaning the connectors can help) or the sensors themselves are faulty c. Replacing the speed sensor on the wheels (front?)
a. Cleaning the contacts on the connections from the BCM (body controller) to the engine control unit (the infamous X101). It is its “improvement” that is described in the next paragraph. b. Replacing or cleaning the accelerator sensor
4. Power supply system:
a. Recharge or change the battery b. Check the generator-battery wire is not subject to chafing and burning (the designers made it quite crookedly)
So, there are a lot of solution options, but in relation to Captiva 3.2, most often this error is associated with the throttle valve and a dirty air filter. Cleaning the damper and replacing the filter is not a difficult task; it will all take you 20 minutes of leisurely twisting the nuts and cleaning the throttle with a carb cleaner. Attention: the throttle valve is attached with four bolts to the intake manifold body, which is made of very soft metal, so be careful with the tightening torque.
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Then I cleared the errors by removing the stamp and the malfunction no longer manifested itself.
3:242 next article:
Generator malfunctions in Chevrolet Captiva
For 1.5 years, Captiva as a whole did not throw out any particularly “electric” surprises, some were inherited, others
Rating 0.00 [0 Votes] 11646
Automatic immobilizer or something else!
A client approached me with a request to diagnose a Lada Granta car, they say the automatic transmission does not work, does not shift from parking and all that, and also the engine stopped starting, well, I think it’s an interesting case, I should go and look at it, maybe I can help with something. )
I arrive at the place and start asking what and how, what caused the breakdown, under what circumstances, in general, the standard questions of any diagnostician. The owner of the car told me about how at first the automatic transmission lever stopped shifting and how he lifted the lever housing, and by pressing the white button, he was able to remove it from parking, put it in neutral, start it and drive away. Further, after driving like this for some time, another problem began, the car began to stall frequently and would not start the first time, and as a result, as always, “on time,” the car refused to start at all. Having thought about what I heard, I decided to connect with a scanner (I have a Scanmatic 2) and read the errors, if any. This is what the ECU scan showed me:
Well, I think somewhere maybe the cable has come off from the ECU, checked everything is in order, started digging further, when you turn on the ignition, the immobilizer icon on the dashboard starts flashing for 10 seconds with a frequency of 1 second, after which it gives a signal twice, then it all repeats again. It seems that the immo doesn’t see it, I take another key, with a red mark, the same thing. I start checking the fuses and switches (they sometimes oxidize or simply don’t work), but everything, as they say, is in good condition. here I get into a stupor, start all over again, connect the scanner, I see the same error U0100, I went back to my brain, since the car was virgin, access to them was made difficult by the carpet, I had to cut it a little, I decided to pull out the connector and look at it with an armed eye, I noticed one a small but important detail, the latch, which was supposed to be closed, was not fully pressed. I pulled out the connector, blew it out, cleaned the contacts, and plugged it back in as far as it would go. and OH MIRACLE everything worked, as they say “it wasn’t the woman’s fault.” ). Apparently, after 7 years of operation, due to an unlatched connector, it came loose and became the cause of such troubles. If this article helps anyone, I will be very happy. Not a nail or a rod for everyone!
In this case, there is no need to flash the “brains” of the car. Firmware for the Lada Granta automatic will most likely not help in solving this problem, so you should look for another reason.
Error u0100 on a Lada Granta with automatic transmission is a fairly common occurrence. The fault code indicates that communication with the engine control unit is broken. The error is manifested by the Check indicator lighting up, but the car will not start.
Main reasons
Today we will try to understand the reasons why the engine refuses to start.
The fuse for the cigarette lighter has blown
Yes, you heard right. AvtoVAZ designers are so ingenious that they installed a fuse on both the cigarette lighter, the horn, and the immobilizer. If the fuse blows, the car will not start at all.
Immobilizer operation
If the key icon flashes when you start the engine, this indicates that there are real problems. You can open the instructions and start looking for the source of the problem. There you can find a description of each breakdown, as well as the signal that corresponds to it. We are talking about the frequency of blinking of the diode.
Error U0100 “CAN bus receiver (ICE) - frequent immobilizer glitch on Grant
If the car does not start until the fourth or even fifth time, then the key may need to be retrained.
Important! Do not confuse a flashing “car with key” warning light with a constantly lit one. If after starting the engine the indicator lights up for about 10 seconds and then turns off, this means that the immobilizer on your car is not activated.
The starter doesn't turn over
The second option would be to operate the starter. In a situation where the immobilizer does not report any problems, we may be talking about the starter. It is easy to determine this malfunction, since when you turn the key you will not hear characteristic sounds. An option for extreme sports enthusiasts, you can try closing the starter with a screwdriver. And if the starter doesn’t turn, then you shouldn’t count on the car starting either.
But the starter may not turn because the battery is discharged. You can check this if the lights on the instrument panel do not light up. Even if they are shining, you will need to turn on the high beams and see if they function normally. If the brightness is low, then such a charge may not be enough to start turning the starter.
You can view the voltage of the on-board circuit in the on-board computer. If the voltage is less than 11.4 Volts, then the starter will not have enough power to crank the engine.
The optimal solution would be to charge the battery or “light it” from someone. Let the car idle for about 10-15 minutes. This will be enough to slightly “restore” the battery power.
Problems with the starter can also have other sources, namely damaged wiring. In this case, a regular tester will come to the rescue. We connect the red contact to the starter, and the black one to the car body. The indicator should be between 12.5 and 14.5 volts. Finding the location of a breakdown can be difficult, especially in the field.
Starter crackling noise when starting
If you experience a similar situation, then removal and repair of the starter is necessary. Otherwise, you risk simply not starting next time!
Electronic control unit
Above we looked at simple reasons why the Lada Granta may not start. It is much more difficult if the electronic control unit, which is simply called the ECU, fails. People call this element “brains”.
There shouldn't be any problems with the ECU if you don't touch it. But, often, a situation occurs when the surface of this element is filled with antifreeze, due to the peculiarities of its location. (problem of the first Lada Kalina cars).
Reasons for the error
On Grant, as a rule, the cause of the error is a malfunction of the engine control module - the computer that controls this very engine and its wiring, or the problem directly lies in the bus through which signals pass to the control module. The cause of the malfunction may lie in the control unit itself, which also fails. To check it, there is a scanner that connects to the diagnostic port, and if the unit does not respond to the actions of the scanner, then you will have to change it. In this case, error u0100 on the Lada Granta with automatic transmission should disappear. It is worth making sure that the terminals of the control unit are not oxidized, and the contacts do not require cleaning from dirt.
Possible reasons
This is not a common problem. In my experience, the most likely problem is the ECM, PCM, or transmission control module. There are at least two locations for the CAN bus in the vehicle. They may be under the carpet, behind the side panels, under the driver's seat, under the dashboard, or between the air conditioning housing and the center console. They provide communication for all modules.
A communication failure between anything on the network will trigger this code. If additional codes are present to isolate the problem, diagnosis is simplified.
