Fault indicators are your vehicles way of letting you know there is a malfunction in one of the onboard systems. The check engine, or service engine soon, light can illuminate for various reasons—some are immediate concerns, but most are emissions related and will not affect performance or cause damage.
Your Cummins diesel engine is being constantly monitored by a various sensors and circuits. These sensors produce signals that are interpreted by the engine computer or engine control module (ECM). The engine computer expects to see certain signal ranges. If the signal ranges are not as expected, a fault will be logged. These signals are monitored constantly by the Cummins ECM.
If a malfunction has occurred, but is not present on the malfunction indicator lamp (MIL), the ECM will store an inactive fault or history code. If the malfunction is current, an active fault code is stored, and the MIL will illuminate or flash. A flashing MIL indicates a serious malfunction, and you should cease operation as soon as safely possible.
How do you know if it is safe to continue operation?
You have to communicate with the ECM, and ask it to tell you what is happening. You can do this by pulling the fault codes. Here’s how:
Procedure for retrieving fault codes on Dodge 6.7 Cummins trucks:
- Select “total miles” on the trucks odometer, not trip.
- Insert ignition key.
- Move the key from LOCK TO OFF, THEN PAUSE.
- Move ignition key to ON/RUN.
- Move ignition key BACK TO OFF.
- Move ignition key to ON/RUN.
- Move ignition key BACK TO OFF.
- Move ignition key to ON/RUN and STOP THERE!
The Key cycles from OFF to ON/RUN should be done in less than 5 seconds.
You then can read the codes on the truck’s odometer. (See complete list below.)
Once you have pulled the codes, contact your Good Sam ERS, and ask to speak to a technician. The tech will be able to advise you on the possibilities and offer further guidance. Once you know the problem, you will have a better idea if you want to work on the repairs yourself or take it to a qualified professional.
ISB fault codes:
A complete list of all Dodge Cummins ISB (5.9 & 6.7L)
- 111 Electronic Control Module ECM Microprocessor
- 115 Engine Speed Sensor ESS Circuit
- 121 Engine Position Sensor EPS Circuit
- 122 Intake Manifold Pressure Sensor Circuit
- 123 Intake Manifold Pressure Sensor Circuit
- 124 Intake Manifold Pressure – Engine Protection
- 131 Accelerator Position Sensor Circuit
- 132 Accelerator Position Sensor Circuit
- 135 Oil Pressure Sensor Circuit
- 141 Oil Pressure Sensor/Switch Circuit Choice
- 141sn Oil Pressure Sensor Circuit
- 141sw Oil Pressure Switch Circuit
- 144 Coolant Temperature Sensor Circuit
- 146 Coolant Temperature – Engine Protection
- 153 Intake Manifold Air Temperature Sensor Circuit
- 154 Intake Manifold Air Temperature Sensor Circuit
- 186 Wait-to-Start Lamp Circuit
- 211 Vehicle Electronic Control Module
- 234 Engine Overspeed Circuit
- 261 Fuel Temperature Sensor Circuit
- 264 VP44 Fuel Temperature Sensor Error
- 278 Lift Pump Circuit
- 283 Engine Speed Sensor Supply
- 284 Engine Speed Sensor Supply
- 291 Datalink Circuit
- 334 Coolant Temperature Sensor Circuit
- 352 Sensor Supply Circuit
- 362 VP44 Fuel Valve High Current Error
- 363 VP44 Fuel Pump Control Valve Feedback Error
- 364 Electronic Control Module ECM to Pump Communications Error
- 365 Fuel Pump Voltage Out of Range Error Low
- 366 VP44 Fuel Pump Voltage Measurement Error
- 367 VP44 Fuel Pump Speed/Position Sensor Signal Lost
- 368 VP44 Fuel Pump Can Not Reach Commanded Timing
- 369 VP44 Fuel Pump To Engine Synchronization Pulse Not Recognized
- 372 Idle Select High/Low
- 373 VP44 Fuel Pump Fuel Shut Off Error
- 374 VP44 Fuel Pump Calibration Error
- 375 Electronic Control Module ECM Fuel Calibration Corrupted
- 376 VP44 Fuel Pump rpm and Fuel Error
- 377 Fuel Pump Power Relay Stuck-On
- 381 Intake Air Heater Relay Circuit
- 382 Intake Air Heater Relay Circuit
- 383 Intake Air Heater Circuit
- 386 Sensor Supply Circuit
- 387 Accelerator Position Sensor Circuit
- 391 VP44 Relay Coil Supply Circuit
- 418 Water-In-Fuel Sensor Circuit
- 429 Water-In-Fuel WIF Sensor Circuit
- 431 Idle Validation Switch IVS Circuit
- 432 Accelerator Pedal Circuit ISS
- 433 Intake Manifold Pressure Sensor Circuit
- 441 Unswitched Battery Supply Circuit
- 442 Unswitched Battery Supply Circuit
- 443 Accelerator Position Sensor Circuit
- 517 VP44 Fuel Pump Valve Feedback Error
- 613 Engine Misfire Detection
- 621 Engine Misfire Detection
- 622 Engine Misfire Detection
- 623 Engine Misfire Detection
- 624 Engine Misfire Detection
- 625 Engine Misfire Detection
- 626 Engine Misfire Detection
- 768 Output Device Driver Transmission Shift Modulation
- 779 OEM Input – Engine Protection
Written by your Good Sam RV technician JD