Cummins/Onan DQFAC troubleshooting: 36 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan DQFAC — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 59 | High AC voltage shutdown | Output voltage on any phase exceeds preset values. Time to trip is inverse. | |
| 197 | Low Coolant Level input is active and the threshold response is set to Shutdown. | 1. Look for possible coolant leakage points and repair if necessary 2. Check coolant level and replenish if low. 3. Reset the control and restart after locating and correcting the problem. | |
| 235 | Low Coolant Level input is active. | 1. Look for possible coolant leakage points and repair if necessary. 2. Check the coolant level and replenish if low. 3. Reset the control and restart after locating and correcting the problem. | |
| 359 | Possible fault with the control or starting system (engine cranks but fails to start). | 1. Check for an empty fuel tank, fuel leaks, or blocked fuel lines and correct as required. 2. Check for a dirty fuel filter and replace if necessary. 3. Check for a dirty or blocked air filter and replace if necessary. 4. Clean and tighten all battery cable connections. 5. Discharged or defective battery. Recharge or replace. 6. Reset the control and restart after correcting the problem. | |
| 415 | Engine oil pressure has dropped below the shutdown trip point. | 1. Check the oil level, lines and filters. 2. If the oil system is OK but the oil level is low, replenish. 3. Reset the control and restart after locating and correcting the problem. | |
| 427 | Communication between the engine control (ECM) and the PCC is severed. | 1. Ensure the E-Stop button is not active. Reset the Local/Remote Emergency Stop. | |
| 441 | Battery voltage is below 24 VDC and is approaching a low level at which unpredictable operation will occur. | 1. Clean battery terminals and tighten all connections. 2. Check the electrolyte level, top up and re-charge (if applicable) 3. Discharged or defective battery. Recharge or replace. | |
| 442 | Battery voltage to the control is approaching a high level (exceeding 32 VDC) at which damage to the control can occur. | 1. Clean the battery terminals and tighten all connections 2. Check the battery charge float level if applicable (lower float level). | |
| 488 | Engine has overheated (intake manifold temperature has risen above the shutdown trip point). | Large load or high ambient temperature may be the cause. | |
| 611 | Engine hot shutdown has occurred (cooldown timers were bypassed). | This type of hot shutdown should be avoided; it can cause possible loss of performance and engine damage. | |
| 781 | Communication between the engine control (ECM) and the PowerCommand® 3.3 control has been severed. | 1. Ensure the E-Stop button is not active. Reset the Local/Remote Emergency Stop. | |
| 1131 | Control is in Battle Short mode (used to bypass several fault shutdowns therefore allowing generator set operation during emergencies). | 1. If possible, investigate any fault codes that are being bypassed. | |
| 1312, 1317, and 1318 | Nature of the fault is an optional customer selection – configurable input #. | 1. Check the Input # requirements and correct if possible. | |
| 1416 | Bypassed shutdown fault while the generator set was in Battle Short mode. | 1. Event/fault 1416 has been activated as a result of another active shutdown fault while the PowerCommand® 3.3 control is operating in Battle Short mode. If possible, troubleshoot this shutdown fault that is causing the generator set to shut down. | |
| 1433/1434 | Local or remote Emergency Stop has been activated. | ||
| 59 | High AC voltage shutdown - Output voltage on any phase exceeds preset values. Time to trip is inversely proportional to amount above threshold. Values adjustable from 105-125% of nominal voltage, with time delay adjustable from 0.1-10 seconds. Default value is 110% for 10 seconds. | ||
| 27 | Low AC voltage shutdown - Voltage on any phase has dropped below a preset value. Adjustable over a range of 50-95% of reference voltage, time delay 2-20 seconds. Default value is 85% for 10 seconds. Function tracks reference voltage. Control does not nuisance trip when voltage varies due to the control directing voltage to drop, such as during a V/Hz roll-off or synchronizing. | ||
| 81 | Under frequency shutdown - Genset output frequency cannot be maintained. Settings are adjustable from 2-10 Hz below reference governor set point, for a 5- 20 second time delay. |
| Symptom | Remedy |
|---|---|
| Battle short mode | If enabled and the battle short switch is active, some shutdown faults will be bypassed. However, emergency stop shutdowns and other critical faults are not bypassed. |
| Derate | The derate function reduces output power of the genset in response to a fault condition. Commands will be issued to reduce load via contact closures or ModBus if on an isolated bus, and by lowering base load kW to target kW if in utility parallel mode. |
| Emergency stop | Annunciated whenever either emergency stop signal is received from an external switch. |
| Low and high battery voltage warning | Indicates status of the battery charging system (failure) by continuously monitoring battery voltage. |
| Weak battery warning | The control system will test the battery each time the genset is signaled to start and indicate a warning if the battery indicates impending failure. |
| Fail to start (overcrank) shutdown | The control system will indicate a fault if the genset fails to start by the completion of the engine crack sequence. |
| Fail to crank shutdown | Control has signaled starter to crank engine but engine does not rotate. |
| Cranking lockout | The control will not allow the starter to attempt to engage or to crank the engine when the engine is rotating. |
| Fault simulation | The control in conjunction with InPower software, allows a technician to verify the proper operation of the control and its interface by simulating failure modes or forcing the control to operate outside of its normal operating ranges. |
| Off load running (protection) | Protects the engine in the event the genset is being called to go off load for too long. |
| Overspeed shutdown | Default setting is 115% of nominal. |
| Low lube oil pressure warning/shutdown | Level is preset (configurable with InPower or HMI) to match the capabilities of the engine used. Control includes time delays to prevent nuisance alarms. |
| High lube oil temperature warning/shutdown | Level is preset (configurable with InPower or HMI) to match the capabilities of the engine used. Control includes time delays to prevent nuisance alarms. |
| High engine temperature warning/shutdown | Level is preset (configurable with InPower or HMI) to match the capabilities of the engine used. Control includes time delays to prevent nuisance alarms. |
| Low coolant temperature warning | Indicates that engine temperature may not be high enough for a 10 second start or proper load acceptance. Can be set up to be a warning or shutdown. |
| High intake manifold temperature shutdown | Level is preset (configurable with InPower or HMI) to match the capabilities of the engine used. Control includes time delays to prevent nuisance alarms. |
| Engine fault detection | Handled inside the engine ECM, fault information communicated via SAE-J1939 data link for annunciation in HMI. |
| This red lamp is lit when the control detects a Shutdown condition. | The generator set cannot be started when this lamp is on. After the condition has been corrected, the lamp can be reset by first pressing the Stop button and then the Reset button. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Large load or high ambient temperature may be the cause.. See the table for the matching fixes.