DTC 51

COMMENT
If normal communication is not possible for a continuous period of one second or more when the battery voltage is 10 volts or more and the engine speed is 450 r/min or more, diagnostic trouble code number "51" is output. Diagnostic trouble code number "51 " is also output if the data being received is abnormal for a continuous period of four seconds under the same conditions.
- DTC 51 can only be caused by internal PCM failure.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the PCM

DIAGNOSIS
STEP 1. Replace the PCM.
Replace the PCM. Recheck for DTCs.
If the malfunction is eliminated, diagnosis is complete.