OBD-II code U0105 indicates the powertrain control module (PCM) has lost communication with the fuel injector control module (FICM). This disrupts the PCM's ability to manage fuel delivery, potentially affecting engine performance and emissions.
The FICM itself may have failed due to internal electrical issues, corrosion, or overheating. This is the most common cause of U0105.
Damaged, corroded, or loose wiring harnesses or connectors can disrupt communication. Common areas include near the engine or along the chassis where wiring is exposed.
A blown fuse or failed relay in the FICM power supply circuit can prevent the module from operating, leading to lost communication.
Insufficient voltage from the battery or alternator can cause the FICM to malfunction or lose communication with the PCM.
Poor grounding, often due to corrosion or loose connections, can interfere with the FICM's ability to communicate with the PCM.
While uncommon, a failure in the PCM's communication circuit could cause U0105. This should only be considered after all other causes are ruled out.
No, the PCM is rarely the cause of U0105. The issue is almost always due to a faulty FICM, wiring problems, or power supply issues. Replacing the PCM should only be considered as a last resort.
Driving with U0105 is not recommended. The engine may run poorly, stall, or fail to start, and continued driving could lead to further damage or unsafe conditions.
A bad FICM typically shows symptoms like rough running, misfires, or no-start conditions. Diagnose by checking power supply, ground, and communication circuits before concluding the FICM is faulty.
Resetting the code without addressing the underlying issue will only temporarily clear it. The code will likely return if the root cause (e.g., faulty FICM or wiring) is not repaired.