The Cummins/Onan C70 is a 56 kW (70 kVA) Diesel standby generator set powered by a Cummins/Onan 4BT3.9-G4 engine. It is available at 254/440 V, 240/416 V, 230/400 V, 220/380 V, 127/220 V, 115/200 V and 110/190 V, DC-phase and 50 Hz. It holds about 10.9 L (2.9 gal) of oil and 21.2 L (5.6 gal) of coolant, with a maximum ambient rating of 50 °C. Starting uses 2 group-2 batteries rated 750 CCA at 12 V. The set measures 1950×1084×1480 mm (76.8×42.7×58.3 in), weighs about 1063 kg (2344 lb) and produces 97 dBA. An integrated tank holds 106 L (28.0 gal), roughly 8 hours of runtime.
The Cummins/Onan C70 is rated 56 kW standby (70.0 kVA).
What engine does the Cummins/Onan C70 use?
The Cummins/Onan C70 is powered by the Cummins/Onan 4BT3.9-G4 engine.
What fuel does the Cummins/Onan C70 use?
The Cummins/Onan C70 runs on Diesel.
What is the oil capacity of the Cummins/Onan C70?
The Cummins/Onan 4BT3.9-G4 engine in the Cummins/Onan C70 has an oil capacity of 10.9 liters.
Troubleshooting
2
Fault codes
Code
Meaning
Cause
251
Unknown J1939 Fault
Can be caused by battery disconnection/isolation without a run data save operation.
Symptoms & remedies
Symptom
Remedy
Flash-out of Fault Codes
1. The diagnostic mode key switch must be in the On (I) position to flash out the fault codes. 2. In the diagnostic mode: a) With no active faults, the Warning and Stop lamps will be illuminated without flashing OR b) With active faults, the ECM will begin to flash out codes by first turning on the Warning lamp. 3. The Warning lamp will then turn off and the ECM will begin flashing the Stop lamp in sequence to represent the active fault code number. 4. As the fault code is flashed, short pauses will occur to indicate completion of each digit. The Warning lamp will illuminate to indicate the beginning of a fault code. 5. The ECM will continue to flash a fault until the operator uses the Fault increment (↑) or decrement (↓) rocker switch to change to a new fault.
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.