If your car is showing the U0100 engine code, it means that your car has lost communication with the engine control module (ECM) and/or the powertrain control module (PCM), which can cost $800 to $1,500 to repair.
A U0100 engine fault code (“Lost Communication with ECM/PCM”) can cause your engine to run hot, shut down, or not start altogether.
Fixing DTC U0100 requires a diagnosis from a repair shop, with fixes running from very minor adjustments to full ECM or PCM replacements running $800 to $1,500.
Common symptoms of this error code include a check engine warning light, a drastic drop in fuel economy, trouble starting your car, and even engine failure.
Engine code U100: “Lost communication with ECM/PCM”
Diagnostic trouble code U0100 is a generic network communication code that means your car’s high-speed controller area network bus (CAN C) can’t receive messages from the engine control module (ECM) and/or the powertrain control module (PCM).
These electronic control units (ECU) serve the following purposes:
ECM: Gathers information about how the engine is functioning, provides the right amount of fuel to the engine, and minimizes emissions.
PCM: Works closely with the ECM to regulate fuel-to-air ratios in your engine.
CAN C: Connect all the other data-collecting devices to your car’s PCM to conduct your car’s mechanics in tandem.
Serious risk:If the line of communication to the car’s CAN-C is lost, your car’s data bus won’t be able to regulate the engine properly. To avoid straining your engine, get a U0100 code checked out by a mechanic as soon as possible.
Costs for fixing engine code U0100 vary greatly
The cost to fix problems associated with DTC U0100 varies greatly depending on the nature of the communication loss and the make of your vehicle.
The bottom line:The PCM acts like the brain in your vehicle, gathering information from the ECM and other modules through the CAN bus. DTC U0100 will be triggered if the CAN-C bus does not receive a periodic message from ECM/PCM to establish connection.
to fix the U0100 engine code; however, you may be able to rule out some issues if you’ve picked up a U0100 code with your OBD II scan tool at home.
What to do:Make sure your car battery is charged and check for broken wires or damaged components inside your car. You may be able to see if wires are disconnected, but if the problem lies in the PCM itself, more complicated repairs will be required.
* checking your rate won’t affect your credit score
FAQs
How do I fix a U0100 engine code?
+
A U0100 engine code may involve a complicated fix that’s best left to the professionals. You can check to make sure your battery is charged and that the wire connections are secure, but there’s not much else you can do unless you have training in advanced car maintenance.
Can I use a PCM from a different make of car?
+
Generally, PCMs are made specifically for your type of car and vehicle manufacturer. For example, buying a Honda PCM for a Ford vehicle will most likely not work and leave you with a useless and expensive PCM.
Estimate your repair costs for free with GarageGuard™
We use cookies to enhance your experience and to analyze performance and traffic. We may also share information about you with our social media partners for advertising purposes. See our Privacy Policy for details, including your options with respect to information we collect and share.