U0105: Lost Communication With Fuel Injector Control Module
Do not keep driving
Expect the engine not to start, or to have cut out.
The important thing to say is that this is not a fuel supply problem, however much it looks like one. The fuel pump, filter, rail pressure and injectors can all be perfect — the module that actually fires the injectors has stopped receiving instructions. Money spent on a pump, filter or injectors on the strength of this would be wasted.
Ask for the module's power supply, its earth, its mounting and its connectors to be checked. These modules are often bolted to metal deliberately so that the mounting carries heat away as well as forming the earth, so a corroded mounting causes both problems at once.
What this code means
The fuel injector control module has stopped being heard from. The general reasoning is at U0100.
A separate injector driver module exists where the injectors need more than an ordinary output stage can provide — piezo injectors on common-rail diesels, which need high voltage to change shape, and hydraulically actuated systems where the driver electronics sit apart from the main module. Losing communication with it means the engine module can still decide how much fuel to deliver and has no way to make it happen.
The result is a no-start or a stall, on an engine with nothing wrong with it and a fuel system that tests perfectly. Rail pressure is correct, the pump is fine, the injectors are fine — and nothing fires, because the instruction is not arriving. That is the same misleading picture P2552 and P2623 produce by other routes, and it sends people to the fuel system for the same reason.
These modules run hot and are often mounted where they get vibration, so their connectors and mountings matter. On several designs the module is bolted to the engine or the inner wing specifically as a heatsink, and a corroded mounting is both an earth fault and a cooling problem at once.
Likely causes
Start here
- Failed power or earth supply to the module · moderate
- Corroded or loose connector · easy
- Damaged data bus wiring · moderate
- Corroded earth connection · easy
Less common
- Blown fuse or failed supply · easy
- Faulty fuel injector control module · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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