The Cummins/Onan GGHH is an engine. It powers generator sets from Cummins/Onan, including the 100 GGHH.
Also known as: Cummins GGHH
How to read your Cummins/Onan engine serial & model number →
| Code | Meaning | Cause | 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. Fault 1 is time delayed while Fault 2 is immediate. The nature of the fault is an optional selection that is determined when the set installation is designed. The undesignated fault functions may also be programmed for non-shutdown or non-time delay. | |
| FAULT 2 | 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. Fault 1 is time delayed while Fault 2 is immediate. The nature of the fault is an optional selection that is determined when the set installation is designed. The undesignated fault functions may also be programmed for non-shutdown or non-time delay. | |
| FAULT 1 or FAULT 2 | 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. | ||
| CHECK ENG | Fault lamp lights but no fault exists. Engine gauges show oil pressure, engine temperature, and frequency (speed) are within normal limits. | The monitor board or a sensor may be at fault. Contact an authorized service center for service. | |
| F1 | Fuse F1 (see Figure 3-4) on ECM has blown (no voltage [B+] at ECM TB1-8) | The wire between ECM TB1-8 and K4-85 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. |
| F3 | There is no remote circuit signal (12 VDC at auxiliary relay board A28-TB1-6) because fuse F3 on the ECM has blown | Fuse F3 on the ECM has blown. | Replace the fuse with one of the same type and amp rating (15 A); 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 7 for remote connections. |
| F2 | Fuse F2 on the ECM has blown | 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. |
| 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. Engine continues to operate. (Engine can be programmed to shut down.) | 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, reduce load if possible by turning off non-critical loads; 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. | 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: check coolant level and replenish if low, look for possible coolant leakage points and repair if necessary; check for obstructions to cooling airflow and correct as necessary; check for a slipping fan belt and tighten if loose; 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.) | Engine oil pressure has dropped to 30 psi (207 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. NOTE: See also step 6. | Engine oil pressure has dropped to 25 psi (172 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 40 to 80 psi (276 to 552 kPa) |
| OVERCRANK lamp lights and engine stops cranking. or Engine runs, shuts down, and LO OIL PRES lamp lights. | Possible fuel system problem | Open any closed fuel shutoff valve; check for dirty or plugged air filter and replace if necessary (see Maintenance section); gaseous fuel delivery to the set is inadequate, contact an authorized service center for service; 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. | Engine has exceeded normal operating speed | Contact an authorized service center for service. |
| SWITCH OFF lamp flashes. | 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 or is in standby mode. | Fuel supply pressure is marginally low (5 inches [127 mm] WC or less) | Check for partially closed shutoff valve, empty propane supply tank; for natural gas fueled sets, check with the gas utility. |
| 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.) | 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: coolant heater not connected to power supply, check for blown fuse or disconnected heater cord and correct as required; check for low coolant level and replenish if required, look for possible coolant leakage points and repair as required; contact an authorized service center if none of the above |
| CHECK ENG fault lamp lights. Engine continues to run or is in standby mode. | The optional low emission air/fuel control has sensed an out-of-specification condition | Contact an authorized service center for service. |
| Fault lamp lights but no fault exists. Engine gauges show oil pressure, engine temperature, and frequency (speed) are within normal limits. | The monitor board or a sensor may be at fault | Contact an authorized service center for service. |
| 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). | Remote circuit breaker is tripped | Reset breaker and restart; contact an authorized service center if breaker trips after resetting. |
| Engine will not crank. | Fault lamp on | Correct fault and reset control. |
| Engine will not crank. | Poor battery cable connections | Clean the battery cable terminals and tighten all connections. |
| Engine will not crank. | Discharged or defective battery | Recharge or replace the battery. |
| Engine will not crank. | 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. |
| Engine will not crank. | Possible fault with control or starting system | Contact an authorized service center if none of the above. |
| No AC output voltage. | Field breaker is tripped | Reset breaker; contact an authorized service center if voltage buildup causes breaker to trip. |
| RUN or fault lamp(s) does not light when Lamp Test switch is engaged. | Contact an authorized service center for assistance. | |
| Green RUN lamp does not light following engine startup. | Possible Start/Disconnect relay failure | Contact an authorized service center for assistance. |
| The engine does not crank in Run mode | 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 to start the genset. |
| The engine does not crank in Run mode | 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 to start the genset. |
| The engine does not crank in Run mode | Cranking voltage is too low to crank the engine. | Clean and tighten or replace the positive (+) and negative (−) battery cable connectors and cables at the battery and the set; Recharge or replace the battery. Specific gravity for a fully charged battery is approximately 1.260 at 80° F (27° C); If the set is in standby service, install a battery charger; Replace the engine-driven battery charging alternator if normal battery charging voltage (12 to 14 VDC) is not obtained. |
| The engine does not crank in Run mode | The wire between ECM TB1-9, K4 and starter terminal BAT is loose damaged or missing. | Check for battery voltage (12 VDC) between ECM TB1-9 (B+) and the grounding stud (−) on the floor of the control cabinet. Check, clean and tighten the connectors at both ends and replace the wire if it is damaged. |
| The engine does not crank in Run mode | 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 engine does not crank in Run mode | The Run-Stop-Remote switch (S12) or wiring is faulty. | 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; 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 engine does not crank in Run mode | The wire between ECM TB1-8, K4 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 engine does not crank in Run mode | 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 engine does not crank in Run mode | The Time Delay Start/Stop Module (A15) is malfunctioning. | Check for constant B+ at A15 terminal TB1-4. Check for run signal at ECM TB1-6. 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 | ECM is faulty. (Check fuses F1 and F4 and for B+ at TB1-9 again.) | 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 engine does not crank in Remote mode | The Run-Stop-Remote switch is at Stop. (The Switch-Off light will be flashing.) | Push the Run-Stop-Remote switch to Remote. |
| The engine does not crank in Remote mode | 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. |
| The engine does not crank in Remote mode | 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. |
| The engine does not crank in Remote mode | 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 7 for remote connections. |
| The engine does not crank in Remote mode | Auxiliary relay board A28 is not functioning properly. | Check for misconnections (see Section 7) 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. |
| The engine does not crank in Remote mode | Same as Steps 3 through 11 in the RUN mode. | See steps 3 through 11 in table Engine Does Not Crank In Run Mode. |
| The engine cranks but does not start | The engine is not getting fuel. | Open any closed fuel shutoff valve. (Valves closed for maintenance or new installations may require several crank cycles to get fuel to genset); Fill the propane supply tank; For natural gas fueled sets, check with the gas utility; Check fuel pressure at regulator (refer to Fuel Pressure in Section 6.) (High fuel pressure will prevent solenoid from opening); Check fuel solenoid (VDC present at K1+ lead during cranking); Duel Fuel Sets Only: Check relay K99. Refer to wiring diagrams in Section 7; Check pressure switch wiring. Propane − normally closed connected to common. Natural gas − normally open connected to common; Check pressure switch function (@ 3.5 inch H2O or less, should switch from natural gas to LPG); Check S14 vacuum switch (optional) for proper operation. |
| The engine cranks but does not start | The air cleaner is blocked. | Service as necessary. |
| The engine cranks but does not start | Fuel solenoid K1 does not energize. | Fuel solenoid not energized by the ECM. Check for B+ at ECM TB1-10 when cranking. If no voltage present and fuse F2 is good replace ECM; Connect B+ to fuel solenoid (K1) terminal BAT. Replace the fuel solenoid if does not “click” when energized. If fuel solenoid is working, check for blocked fuel line or fuel filter. |
| The engine cranks but does not start | Low engine temperature is causing 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. |
| The engine cranks but does not start | Cranking voltage is too low to reach required cranking speed. | While cranking the engine, measure voltage directly across the battery terminals and then immediately across the starter motor terminal and the grounding bolt on the block. Cable, terminal or relay contact resistance is too high if the difference is more than 2 volts. Service as necessary; Recharge or replace the battery. Specific gravity for a fully charged battery is approximately 1.260 at 80° F (27° C); Replace the engine-driven battery charging alternator if normal battery charging voltage is not between 12 and 14 volts. |
| The engine cranks but does not start | Governor inoperable. Type A or B, see Section 6. | Replace governor. |
| The engine cranks but does not start | The engine ignition system is malfunctioning. Refer to wiring diagrams in Section 7. | V6 Engine: Check for battery VDC at coil while cranking. (Red wire with green stripe.); Spec C − Check Ford engine harness ground lead connection; Spec C − Check 10 amp fuse located on Ford engine harness power block; Check crank position sensor (315 to 385 ohms); Check ignition coil (0.5 to 1.3 ohms); Replace ignition module if above items are OK. V10 Engine: Check for battery VDC at ignitor coil while cranking. (Red wire with green stripe.); Spec D − Check three fuses located on Ford engine harness power block; Spec D − Check B+ power connection of Ford engine harness power lead (starter motor stud − B1); Check crank position sensor (315 to 385 ohms); Check cam position sensor (315 to 385 ohms); Check ignition coil primary (0.5 to 1.3 ohms); Replace ignition module if above items are OK. |
| The engine cranks but does not start | The magnetic speed pick-up is defective or requires adjustment. | Refer to Magnetic Speed Pickup Unit Adjustment in Section 6. |
| The engine cranks but does not start | Incorrect main fuel valve adjustment. | Refer to Gaseous Fuel Adjustment (Type A or B) in Section 6. |
| The engine cranks but does not start | Incorrect secondary regulator adjustment. | Refer to Initial Secondary Regulator Adjustment in Section 6. |
| The engine runs until fault shutdown | The OVERSPEED lamp comes on and the engine shuts down. | Reset the ECM by pushing the Run-Stop-Remote switch to Stop and the Reset switch to Reset and restart the set, monitoring engine speed; Adjust the governor for Type A fuel system/check operation of Type B integrated governor (see Section 6); Type A: If the governor cannot be adjusted to prevent shutdown due to overspeed, check for binding in the linkage. Repair and adjust the linkage as necessary; Type A and B: If the set still shuts down due to overspeed, re-install the magnetic speed pick-up unit to make sure the clearance with the flywheel gear teeth is correct (see Section 6). Replace the speed-pickup unit if output voltage at cranking speed is less than 1.5 VAC. (Intermittent open on magnetic speed pick-up lead can also cause an overspeed condition.); Replace the governor controller board (Type A) or integrated governor assembly (Type B) if the set still shuts down due to overspeed. |
| The OVERSPEED lamp comes on and the engine shuts down within 1 to 5 seconds (no overspeed condition detected). (V6 Spec A & B, V10 Spec A−C) | Remove K5-30 lead from K5. Start genset. If set shuts down and overspeed light is on, replace ECM (A11); Remove K5-30 lead from K5 and check lead continuity to ground. If ground present, replace ignition module; Connect K5-30. Remove lead K5-87 and check lead continuity to ground. If ground present, replace K5 relay; Remove K5-87 lead from K5 and start genset. If set shuts down and OVERSPEED lamp comes on, replace ECM (A11); Check Ford engine harness oil pressure lead for proper ground to intake manifold. Must be grounded to prevent false ignition module fault. | |
| The OVERSPEED lamp comes on and the engine shuts down after 1 or more minutes (no overspeed condition detected). | Low coolant; Air in cooling system; Defective engine cylinder switch. | Fill cooling system; Bleed cooling system; Remove plug from engine cylinder switch. Start genset. If no fault, switch is defective. (This switch is not used by the control, but can cause fault condition if defective.) |
| The LO OIL PRES lamp comes on and the engine shuts down within 10 to 15 seconds (Overspeed lamp is off). | Low oil pressure. | Check the engine oil level, repair any oil leaks and fill to the proper level. Then reset the ECM by pushing the Run-Stop-Remote switch to Stop and the Reset switch to Reset; If the set still shuts down due to low oil pressure, restart the set and observe oil pressure while cranking the engine. Service the lubricating oil system according to the engine service manual if oil pressure is less than 25 psi (173 kPa); If engine oil pressure is proven to be correct and the set still shuts down due to low oil pressure, replace the low oil pressure sender. See Section 3 to locate the sender; Defective Sensor (A27) board. Remove plug from A27 and start set. If set continues to run, replace A27. Refer to Section 3 for A27 board connections; Check S14 vacuum switch (optional) for proper operation. |
| The LO OIL PRES lamp comes on and the engine shuts down after 1 or more minutes (Overspeed lamp is off). | Low oil pressure. | See step 4 in this table; See steps 1, 8 and 9 in table Engine Cranks But Does Not Start. |
| The HI ENG TEMP lamp comes on and the engine shuts down. | High engine temperature. | Check the engine coolant level, repair any coolant leaks and refill as necessary. Then reset the ECM by pushing the Run-Stop-Remote switch to Stop and the Reset switch to Reset; If the set still shuts down due to high engine temperature, start the engine and observe coolant temperature as the system heats up. If coolant temperature exceeds 230° F (110° C), clean and service the entire cooling system as required to restore full cooling capacity; If shutdown occurs before the coolant reaches 230° F (110° C), replace temperature sender if the voltage across the sender terminals is less than 1.1 VDC. See Section 3 to locate the temperature sender; Defective Sensor board. Refer to Section 3 for Sensor board connections; Defective engine thermostat. Service the engine according to the engine service manual. |
| The FAULT 1 or FAULT 2 lamp comes on and the engine shuts down. | Customer-supplied system fault indication switches; low frequency; over/under voltage. | Service as required. (The customer has supplied the system fault indication switches. Either fault can be chosen to display the warning only. See Section 3.); If the shutdown was due to low frequency, the set probably ran out of fuel or the governor is out of adjustment; If the shutdown was due to over/under voltage, the voltage regulator may be out of adjustment. |
| The engine lacks power or is unstable | Current ambient conditions cause a derate, limiting power to less than rated power. | Determine proper derates for ambient conditions. Refer to specification sheet for site derating factors. |
| The engine lacks power or is unstable | The engine air filter element is dirty. | Replace the air filter element. |
| The engine lacks power or is unstable | The gaseous fuel is of insufficient energy content. | Check with the propane supplier or the gas utility to confirm the energy content of the gaseous fuel being used. Propane must have approximately 2500 BTU’s per cubic foot and natural gas 1000 BTU’s per cubic foot. |
| The engine lacks power or is unstable | LPG liquid converter frosts. | Low coolant. Fill cooling system; Air in cooling system. Bleed cooling system. |
| The engine lacks power or is unstable | The governor or gas mixer adjustments are incorrect. | Make gas mixer or governor settings and adjustments for Type A and B fuel systems according to Section 6, Governor; Check the magnetic speed pick-up unit (MPU) clearance with flywheel. Replace the MPU if output voltage at cranking speed is less than 1.5 VAC; Type A: If the governor cannot be adjusted for full power or stable speed, shut down the set and check for binding in the linkage. Repair and adjust the linkage as necessary; Type B: With the genset off, connect lead marked ALT DYN to lead marked T26 at governor. If governor stability is OK, leave connection; Type A: Replace the governor controller board. Type B: Replace the integrated governor assembly. |
| Engine hunting at 90% to 100% of full load. | Type B adaptive governor feature; K99 relay miswired; governor or gas mixer adjustments incorrect. | Type B: This governor is equipped with a adaptive feature, which can affect the operation of the genset. If the genset was hunting excessively prior to attempting full load operation, the lower gain value may affect full load operation and transient performance. Stopping and restarting the genset will return the gain values to normal; Type B: No Air/Fuel adjustment available − check K99 wiring (see Section 7). K99 relay, miswired, can cause genset hunting; Type A and B − See step 5 of this table. |
| Engine misfires on LPG or NG or backfires on LPG at high loads | Air fuel ratio too lean; spark plugs/gap; spark plug wires; ignition coil primary; defective LPL converter. | Air fuel ratio too lean. Adjust main fuel valve. Refer to Gaseous Fuel Adjustment (Type A or B) in Section 6; Inspect spark plugs/gap. GGFD, GGFE, GGEH GGHF = 0.044” / GGHG, GGHH = 0.032; Check spark plug wires (6,000 ohms/foot); Check ignition coil primary (0.5 to 1.3 ohms); LPG liquid withdrawal − defective LPL converter. |
| Engine has preignition on LPG at high loads. | Ignition timing. | Check ignition timing, refer to Section 6. |
| The engine lacks power or is unstable | Gaseous fuel delivery (vapor withdrawal) to the set is inadequate or fuel pressure is to high at light loads. | Check the gas supply pressure at the regulator input. Make necessary provisions so that gas supply pressure is at least 7 inches (178 mm) Water Column (WC) when the set is under full load, and not more than 13.6 inches (345 mm) WC. |
| The engine lacks power or is unstable | The MAP sensor is defective (V10 turbo only). | Check operation of MAP sensor, refer to Section 3. |
| The engine lacks power or is unstable | Excessive crank time before starting (LPG liquid withdrawal fuel systems with Impco Model E convertor). | Check operation of K1-SV converter priming solenoid. Remove black cover and visually check solenoid operation during cranking. |
| Excessive crank time (seven seconds or more) before starting (NG or LPG vapor) | Inadequate fuel pressure; regulator (model RZ) may require adjustment. | See step 9 in this table; Regulator (model RZ) may require adjustment. Refer to Initial Secondary Regulator Adjustment in Section 6. |
| The engine lacks power or is unstable | The engine is worn. | Service the engine according to the engine service manual. |
| An amber warning lamp is on — The PRE LO OIL PRES lamp comes on while the engine is running. | Pre low oil pressure (less than 30 psi (207 kPa) but greater than 25 psi (173 kPa)); Sensor board or oil pressure sender. | Shut down the set if possible or disconnect non-critical loads. Pre lo oil pressure will be less than 30 psi (207 kPa) but greater than 25 psi (173 kPa). Service the engine lubricating system according to the engine service manual; If engine oil pressure is proven to be correct and the pre lo oil pressure lamp is on, the problem may be the Sensor board or the oil pressure sender. Refer to Section 3 for Sensor board connections. |
| An amber warning lamp is on — The PRE HI ENG TEMP lamp comes on while the engine is running. | Pre high engine temperature (greater than 220° F (104° C) but less than 230° F [110° C]); Sensor board. | Shut down the set if possible or disconnect non-critical loads. (Engine temperature will be greater than 220° F (104° C) but less than 230° F [110° C.]) Service the engine cooling system to restore full cooling capacity; If the engine cooling system is functioning properly, the problem may be the Sensor board. Refer to Section 3 for Sensor board connections. |
| An amber warning lamp is on — The LOW ENGINE TEMPERATURE lamp comes on while the set is in standby. | Engine coolant heater not operating; Sensor board. | Plug in, repair or install engine coolant heater; If engine coolant heater is operating properly, the problem may be the Sensor board. Refer to Section 3 for Sensor board connections. |
| An amber warning lamp is on — The LOW FUEL lamp (optional) comes on while the set is in standby or the engine is running. | Fuel supply pressure is 5 inches (127 mm) WC or less for dual or single fuel systems; with dual fuel system, genset is operating on secondary fuel supply; fuel pressure switch (S11) operation/wiring; K99 relay operation/wiring. | Indicates fuel supply pressure is 5 inches (127 mm) WC or less for dual or single fuel systems. With dual fuel system, also indicates that genset is operating on secondary fuel supply. Fill the propane supply tank or for natural gas fueled sets, check with the gas utility; Dual Fuel Systems: Check operation/wiring of fuel pressure switch (S11); Check operation/wiring of K99 relay. |
| An amber warning lamp is on — The FAULT 1 or FAULT 2 lamp (may be a specifically labeled amber lamp) comes on. | Customer-supplied system fault indicating switches. | Service as required. (The customer has supplied the system fault indicating switches. By means of selection jumpers, either fault may be chosen to shut down the engine. See Section 3, Engine Control.) |
| Low emissions genset only — The CHECK ENGINE lamp comes on at no load. | Normal during no load, cold ambient condition. | This is normal during no load, cold ambient condition. Increase genset load to 10% or more, lamp should turn off. To verify system operation, disconnect O2 sensor and reconnect after 1 minute. Genset speed will change slightly (air fuel ratio will go lean momentarily) indicating system is working properly. |
Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing. Showing the first 80 of 248 entries.
Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan GGHH.
Step-by-step procedures compiled from the Cummins/Onan service manual for this engine.
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 277/480 | 3 | WYE, 4 wire |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
The Cummins/Onan GGHH powers 1 generator set(s), including Cummins/Onan 100 GGHH.
A commonly reported issue on generators using the Cummins/Onan GGHH is: Over Current.