U0100
Lost Communication With ECM/PCM 'A'
This code means that one or more of the vehicle's computer modules has lost communication with the main engine and transmission computer (the ECM/PCM). It's like different parts of the car's 'nervous system' can't talk to its 'brain'.
Lost Communication With Engine Control Module/Powertrain Control Module 'A'
Common causes
- high
Faulty ECM/PCM
The engine's main computer itself may have failed, preventing it from communicating with other modules.
Typical part cost: $500-1500+ part
- medium
Wiring/Connector Issues (CAN Bus)
Damaged, corroded, or loose wiring in the CAN (Controller Area Network) bus system can interrupt communication.
Typical part cost: $0-300 repair
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First things to check
- 1Check all fuses related to the ECM/PCM and other modules on the CAN bus.
- 2Inspect the ECM/PCM connectors and wiring harness for damage, corrosion, or looseness.
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Related codes
See related trouble codes
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Frequently asked questions
What is the CAN bus?
The CAN (Controller Area Network) bus is a communication network that allows different electronic control units (computers) in your car to share information and signals with each other efficiently.
Can a dead battery cause a U0100 code?
A severely weak or dead battery, or poor battery connections, can cause voltage fluctuations that lead to communication errors and trigger U-codes like U0100. Always check battery health first.
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