High voltage on the (+) 5 volt supply line can be caused by a short to battery voltage in the engine harness or connectors, or a malfinctioning ECM.
1)Relace the ECM.2)Repair or replace the engine harness.3)Replace the OEM harness.
Cummins ISX CM870 (2003-06) Fault Code: 352 PID: S232 SPN: 1079 FMI: 4/4 Sensor Supply 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at sensor supply number 1 circuit.
Cummins ISX CM870 (2003-06) Fault Code: 343 PID: S254 SPN: 629 FMI: 12/12 Electronic Control Module Warning Internal Hardware Failure – Bad Intelligent Device or Component. ECM power supply errors have been detected.
Cummins ISX CM870 (2003-06) Fault Code: 341 PID: S253 SPN: 630 FMI: 2/2 Engine control module (ECM) data lost.
Cummins ISX CM870 (2003-06) Fault Code: 339 PID: S087 SPN: 1267 FMI: 4/4 Idle Shutdown Vehicle Accessories Relay Driver Circuit – Voltage Below Normal, or Shorted to Low Source. Low voltage detected at the idle shutdown vehicle accessory or ignition bus relay circuit when commanded ON.
Cummins ISX CM870 (2003-06) Fault Code: 338 PID: S087 SPN: 1267 FMI: 3/3 Idle Shutdown Vehicle Accessories Relay Driver Circuit – Voltage Above Normal, or Shorted to High Source. Open circuit or short to voltage source detected at the idle shutdown vehicle accessory/ignition bus relay circuit.
Cummins ISX CM870 (2003-06) Fault Code: 319 PID: P251 SPN: 251 FMI: 2/2 Real-Time Clock Power Interrupt – Data Erratic, Intermittent, or Incorrect. Real-time clock lost power
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