MERCEDES · DTC LOOKUP
Mercedes W204 ECU comm fault — W204 C-Class ECU not communicating
Mercedes diagnostic code. Below: what it means, common causes, symptoms, and the exact bench-programming fix path.
Common causes
- •ECU internal failure
- •CAN-bus fault from failing EIS/ELV
- •Power supply fault
Symptoms you'll see
- •No ECU comm
- •Multiple secondary comm faults
- •Engine won't start
The fix path
Diagnose root cause first. If EIS/ELV is the real culprit (most common on W204), bench-fix that. ECU repair is also available — contact us.
AML services that fix this
Mail in the affected module, we bench-program, ship back next business day. Flat pricing, return shipping included.
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Related diagnostic codes
U0001High Speed CAN Communication Bus ErrorSteering lock faultMercedes Electronic Steering Lock (ELV) failureEIS not reading keyMercedes EIS fails to authenticate inserted keyCrank-no-startEngine cranks normally but won't startP164BEngine Stop Detected — Immobilizer ActivatedMercedes W220 EIS failureW220 S-Class EIS authentication failureNot sure which service applies?
Text us your year/make/model + which scanner caught the code — we'll tell you exactly which module to ship and which service to pick.