Cummins/Onan DGHE troubleshooting: 43 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan DGHE — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Remedy |
|---|---|---|
| FAULT 1 | The FAULT 1 or FAULT 2 fault lamp lights. Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. | The standard undesignated fault functions are programmed to shut down the set when a fault is sensed. |
| 14 | Remote circuit breaker is tripped. | Reset breaker and restart. Contact an authorized service center if breaker trips after resetting. |
| 16 | Engine will not crank. | Indicates possible fault with control or starting system. Check for the following conditions: a. Fault lamp on. Correct fault and reset control. b. Poor battery cable connections. Clean the battery cable terminals and tighten all connections. c. Discharged or defective battery. Recharge or replace the battery. d. Emergency stop button (if equipped) pushed in. To reset, pull switch out and move Run/Stop/Remote switch to Stop position. Then push test switch to Reset/Lamp position. e. Contact an authorized service center if none of the above. |
| 17 | No AC output voltage. | Field breaker is tripped. Reset breaker. Contact an authorized service center if voltage buildup causes breaker to trip. |
| 18 | RUN or fault lamp(s) does not light when Lamp Test switch is engaged. | Contact an authorized service center for assistance. |
| 19 | Green RUN lamp does not light following engine startup. | Indicates possible Start/Disconnect relay failure. Contact an authorized service center for assistance. |
| Symptom | Cause | Remedy |
|---|---|---|
| Green RUN lamp lights following engine startup. | Indicates all engine systems are normal. No corrective action required. | |
| PRE HI ENGINE TEMP lamp lights. | Indicates engine has begun to overheat and engine temperature has risen to approximately 220°F (104° C) or coolant level is low on optionally wired sets. If generator is powering non-critical and critical loads and cannot be shut down, use the following: a. Reduce load if possible by turning off non-critical loads. b. Check air inlets and outlets and remove any obstructions to airflow. If engine can be stopped, follow procedure in step 3. | |
| HI ENG TEMP lamp lights. Engine shuts down. | Indicates engine has overheated (engine temperature has risen above 230°F/110°C) or coolant level is low. Allow engine to cool down completely before proceeding with the following checks: a. Check coolant level and replenish if low. Look for possible coolant leakage points and repair if necessary. b. Check for obstructions to cooling airflow and correct as necessary. c. Check for a slipping fan belt and tighten if loose. d. Reset control and restart after locating and correcting problem. Contact an authorized service center if none of the above. | |
| PRE LO OIL PRES lamp lights. Engine continues to operate. (Engine can be programmed to shut down.) | Indicates engine oil pressure has dropped to 20 psi (138 kPa). If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow step 5 procedure. If engine can be stopped, follow procedures in step 5. | |
| LO OIL PRES lamp lights. Engine shuts down. | Indicates engine oil pressure has dropped to 14 psi (97 kPa). Check oil level, lines and filters. If oil system is OK but oil level is low, replenish. Reset control and restart. Contact an authorized service center if oil pressure is not in the range of 25 to 40 psi (172 to 275 kPa). | |
| OVERCRANK lamp lights and engine stops cranking. | Or Engine runs, shuts down, and LO OIL PRES lamp lights.. a. Check for empty fuel tank, fuel leaks, or plugged fuel lines and correct as required. b. Check for dirty fuel filter and replace if necessary (see Maintenance section). c. Check for dirty or plugged air filter and replace if necessary (see Maintenance section). d. Reset the control and restart after correcting the problem. Contact an authorized service center for service if none of the above. | |
| OVERSPEED lamp lights and the engine shuts down. | Indicates engine has exceeded normal operating speed. Contact an authorized service center for service. | |
| SWITCH OFF lamp flashes. | Indicates Run/Stop/Remote switch is in the Stop position which will prevent automatic starting if an automatic transfer switch is used. Move the Run/Stop/Remote switch to the Remote position for automatic starting. | |
| LO FUEL lamp lights. Engine continues to run. | Indicates diesel fuel supply is running low. Check fuel supply and replenish as required. | |
| LO FUEL LAMP lights. Engine shuts down and LO OIL PRES lamp lights. | Indicates engine has run out of fuel. Check fuel level and replenish as required. | |
| LO ENG TEMP lamp lights. Set is in standby mode but is not operating. (Lamp lights when engine coolant temperature is 70° F (21° C) or lower. Since the lamp goes out after the engine warms up, there should be no cause for alarm even during initial generator set operation.) | Indicates engine coolant heater is not operating, not circulating coolant or ambient temperature too cold for heater to keep up with demand. Check for the following conditions: a. Coolant heater not connected to power supply. Check for blown fuse or disconnected heater cord and correct as required. b. Check for low coolant level and replenish if required. Look for possible coolant leakage points and repair as required. c. Contact an authorized service center if none of the above. | |
| If these conditions occur, the engine monitor activates a fault lamp, and may also stop the engine (depending on the condition). | This section describes the fault condition system, and suggests troubleshooting procedures. | |
| Engine starts from generator control panel but will not start automatically or from a remote panel. | (Note: The Run/Stop/Remote switch must be in the Remote position for automatic or remote starting). | |
| The grounding strap between the control box and the battery negative (–) terminal or the ground wire between the control and engine ground is loose, damaged or missing. | Check for continuity (zero ohms) between the grounding stud on the bottom of the control box and the battery negative (–) terminal. If there is no continuity or the grounding strap is loose or damaged, repair as necessary. | |
| The Run-Stop-Remote switch (S12) or wiring is faulty. | A. Disconnect pin connector J4 from the ECM and check for electrical continuity (zero ohms) between switch terminals 2 and 3 when the switch is in the Run position and between terminals 1 and 2 when it is in the Remote position. Replace the switch if either set of contacts is faulty. b. If the switch works, check for electrical continuity (zero ohms) between J4-6 and J4-7 on the wire harness when the switch is in the Run position and between J4-5 and J4-7 when the switch is in the Remote position. Repair the wire harness if there is no electrical continuity in either position of the switch. | |
| The ECM is faulty. | Push the Run-Stop-Remote switch to Run and check for battery voltage (12 VDC) at ECM TB1-8. Replace ECM if there is no voltage at ECM TB1-8 but 12 VDC at ECM TB1-9. | |
| The wire between ECM TB1-8 and starter solenoid terminal SW is loose, damaged or missing. | Push the Run-Stop-Remote switch to Run and check for battery voltage (12 VDC) at starter solenoid terminal SW. If there is no voltage repair the wiring as necessary. | |
| The starter motor or solenoid is malfunctioning. | Push the Run-Stop-Remote switch to Run and check for battery voltage (B+) at starter solenoid terminal SW. Replace the starter motor if there is voltage but the motor does not function. | |
| The Time Delay Start/Stop Module (A15) is malfunctioning. | Check for constant B+ at A15 terminal TB1-4. Check for run signal at ECM TB1-5. Voltage at A15 TB1-6 should be at B+ at the end of the start delay period. Check wiring and connections from A15 TB1-6 to ECM TB1-6. | |
| The engine does not crank in RUN mode. | 1. The Run-Stop-Remote switch is at Stop. (The Switch-Off light will be flashing, if provided.) Push the Run-Stop-Remote switch to Remote. 2. The Emergency Stop switch has been used. (The switch button is lit.) Pull the Emergency Switch button. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Remote. 3. A Fault Shutdown is being indicated by one of the red lights on the control panel. Service the set as necessary. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Remote. 4. There is no remote circuit signal (12 VDC at auxiliary relay board A28-TB1-6) because fuse F3 on the ECM has blown. a. Replace the fuse with one of the same type and amp rating (15 A). b. If fuse F3 blows again, find and repair the fault in the remote control circuit, such as a loose wire that may be shorting to ground or a shorted relay coil or other component. See Section 8 for remote connections. 5. There is no remote circuit signal (12 VDC at auxiliary relay board A28-TB1-6) because the remote circuit is not functioning properly. Apply 12 VDC to A28-TB1-6. If the engine cranks, find and repair the fault in the remote control circuit. See Section 8 for remote connections. 6. Auxiliary relay board A28 is not functioning properly. Check for misconnections (see Section 8) or loose connections and replace auxiliary relay board A28 if there is 12 VDC at terminal A28-TB1-6 but not at A28-J2-6. 7. Same as Steps 3 through 11 in the RUN mode. See steps 3 through 11 in the preceding RUN mode. | |
| The engine cranks but does not start. | 1. The engine is not getting fuel. a. Open any closed fuel shutoff valve. b. Fill the main fuel supply tank. c. Restore fuel pump prime according to the engine service manual. 2. Fuse F2 on the ECM has blown. Replace fuse with one of the same type and amp rating. If fuse F2 blows again, the wire between ECM TB1-10 and engine block terminal T26, or a wire between terminal T26 and an accessory may be loose or shorting to ground. 3. Fuel solenoid K1 does not energize. | |
| B+ at ECM TB1-10 not present when cranking | No voltage present and fuse F2 is good | Replace ECM |
| B+ to fuel solenoid (K1) terminal BAT does not 'click' when energized | Replace the fuel solenoid if it does not ‘click’; check for blocked fuel line or fuel filter | |
| Low engine temperature causes too low a cranking speed for starting | Increase room temperature, plug in, repair or install engine coolant heater; replace the engine oil if it is not of the recommended viscosity for the ambient temperature | |
| Cranking voltage too low to reach required cranking speed | Measure voltage across battery terminals and starter motor terminal; service as necessary if cable, terminal or relay contact resistance is too high; recharge or replace the battery; replace engine-driven battery charging alternator | |
| Air cleaner blocked | Service as necessary | |
| Ignition system, fuel system or other engine malfunction | Service according to the engine service manual | |
| Engine runs until fault shutdown due to overspeed | Overspeed module (PMG equipped sets) or overspeed switch cannot be adjusted; governor adjustment issue; linkage binding; speed pick-up unit output voltage less than 2.5 VDC; actuator unit does not drive the linkage through its full travel when power is connected or return it when power is disconnected; governor controller issues | Reset ECM, adjust governor, repair and adjust linkage as necessary, re-install magnetic speed pick-up unit to ensure correct clearance with flywheel gear teeth, replace speed-pickup unit if output voltage at cranking speed is less than 2.5 VDC, replace actuator or governor controller |
| Engine runs until fault shutdown due to low oil pressure | Check engine oil level, repair any oil leaks and fill to proper level; reset ECM if set still shuts down; service lubricating oil system according to engine service manual if oil pressure is less than 14 psi (97 kPa); replace low oil pressure cutout switch if oil pressure is greater than 14 psi (97 kPa) | |
| Engine runs until fault shutdown due to high engine temperature | Check engine coolant level, repair any coolant leaks and refill as necessary; reset ECM if set still shuts down; start engine and observe coolant temperature as system heats up; replace high engine temperature cutout switch if shutdown occurs before coolant reaches 230° F (110° C); clean and service cooling system as required to restore full cooling capacity | |
| Engine runs until fault shutdown due to fault indication switches | Service as required; if shutdown was due to low frequency, check for fuel supply or governor adjustment issues; if shutdown was due to over/under voltage, check voltage regulator | |
| Engine lacks power or is unstable | Fuel delivery to the genset is inadequate | Service as necessary |
| The Emergency Stop switch has been used. | The switch button is lit. | Pull the Emergency Switch button. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Run. |
| A Fault Shutdown is being indicated by one of the red lights on the control panel. | Service the set as necessary. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Run. | |
| A LO Shutdown is being indicated on the day tank pump control panel. | Determine the cause and service as necessary (See Section 7). To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Run or Remote. Note that the engine control will shut down unless the day tank control has been reset first. | |
| Cranking voltage is too low to crank the engine. | A. Clean and tighten or replace the positive (+) and negative (–) battery cable connectors and cables at the battery and the set. b. Recharge or replace the battery. Specific gravity for a fully charged battery is approximately 1.260 at 80° F (27° C). c. If the set is in standby service, install a battery charger. d. Replace the engine-driven battery charging alternator if normal battery charging voltage (12 to 14 VDC) is not obtained. | |
| Fuse F1 on ECM has blown (no voltage [B+] at ECM TB1-8). | The wire between ECM TB1-8 and starter terminal B1-SW or the wires between TB1-8 – resistor /diode assembly – battery charging alternator may be loose and shorting to ground. | Repair as necessary and replace the fuse with one of the same type and amp rating (20 A). If fuse continues to blow, service or replace the starter, relay K4, or the resistor/diode assembly. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: No voltage present and fuse F2 is good. See the table for the matching fixes.
Documented causes: Overspeed module (PMG equipped sets) or overspeed switch cannot be adjusted; governor adjustment issue; linkage binding; speed pick-up unit output voltage less than 2.5 VDC; actuator unit does not drive the linkage through its full travel when power is connected or return it when power is disconnected; governor controller issues. See the table for the matching fixes.
Documented causes: Fuel delivery to the genset is inadequate. See the table for the matching fixes.