Cummins ISB CM850 (2003-06) Fault Code: 386 PID: SID 212 SPN: 1079 FMI: 3 Sensor Supply Voltage number 1 Circuit – Voltage Above Normal or Shorted to High Source. High voltage detected at sensor supply number 1 circuit.

Posted by PerDiezel Solutions on January 18, 2026

High voltage on the sensor supply line can be caused by an individual sensor supply wire in the harness shorted to battery voltage or a failed ECM power supply.

On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines):

1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2)The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The MIL lamp and fault code can also be cleared using the INSITE? service tool.
3)The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

On-Board Diagnostics (OBD) Information (Euro 4 Stage 1+ Certified Engines):

1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2)An engine torque derate will be activated after 50 hours of engine operation with the fault code active.
3)The ECM turns OFF the malfunction indicator lamp (MIL) after 1 ignition cycle that the diagnostic runs and does not fail. The MIL lamp cannot be cleared using the INSITE? service tool.
4)The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Possible repairs:

1)Repair or replace the engine harness.
2)Replace the ECM.
3)Repair or replace the OEM harness.

Cummins ISB CM850 (2003-06) Fault Code: 352 PID: SID 212 SPN: 1079 FMI: 4 Sensor Supply Voltage Number 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at sensor supply number 1 circuit.

Cummins ISB CM850 (2003-06) Fault Code: 351 PID: SID 254 SPN: 627 FMI: 12 Injector Power Supply – Bad Intelligent Device or Component. The ECM measured injector boost voltage is low.

Cummins ISB CM850 (2003-06) Fault Code: 343 PID: SID 254 SPN: 629 FMI: 12 Engine Control Module Warning Internal Hardware Failure – Bad Intelligent Device or Component.

Cummins ISB CM850 (2003-06) Fault Code: 342 PID: SID 253 SPN: 630 FMI: 13 Electronic Calibration Code Incompatibility – Out of Calibration. An incompatable calibration between the primary and secondary OEM installed ECM’s has been detected.

Cummins ISB CM850 (2003-06) Fault Code: 341 PID: SID 253 SPN: 530 FMI: 2 Engine Control Module Data Lost – Data Erratic, Intermittent or Incorrect. Severe loss of data from the ECM.

Cummins ISB CM850 (2003-06) Fault Code: 334 PID: 110 SPN: 110 FMI: 2 Engine Coolant Temperature – Data Erratic, Intermittent, or Incorrect. The engine coolant temperature reading is not changed with engine operating conditions.

WARNING!