The 550 is a generator-set controller. It is used on generator sets from Kohler, including the 100EFOZ, 125EOZ, 125REZG and 30REOZJ.
| Symptom | Cause | Remedy |
|---|---|---|
| Cranks but does not start | Battery connections loose, corroded, or incorrect | Verify that the battery connections are correct, clean, and tight. |
| Display is black | No/low battery charge | Recharge/replace battery |
| Display locks up | No/low battery charge | Recharge/replace battery |
| Display shows an EEPROM WRITE ERROR message | EEPROM fault caused by component failure, lightening strike, or voltage spike | Reinitialize the problem data block; Contact an Authorized Distributor/Dealer |
| Display shows an error message | Controller firmware or keypad entry error | Review the Request and Error Message Section |
| Display shows single segment | Low battery voltage | Recharge battery |
| Displays error message/locks up | Controller firmware error | Review the controller display troubleshooting chart. |
| Does not crank | Battery connections loose, corroded, or incorrect | Verify that the battery connections are correct, clean, and tight. |
| Excessive or abnormal noise | Compression weak | Check the compression. |
| Exercise run time and/or event records inoperative | Controller clock not set | Reset time and date. |
| High fuel consumption | Air cleaner clogged | Clean or replace the filter element. |
| Lacks power | Air cleaner clogged | Clean or replace the filter element. |
| Low oil pressure | Crankcase oil type incorrect for ambient temperature | Change the oil. Use oil with a viscosity suitable for the operating climate. |
| No or low output voltage | AC output circuit breaker open | Reset the breaker and check for AC voltage at the generator set side of the circuit breaker. |
| Output voltage ramps | Defective exciter winding | Troubleshoot alternator components |
| Output voltage unstable | Voltage regulation calibration incorrect | Readjust voltage regulation |
| Overheats | Engine overload | Reduce the electrical load. See the generator set spec sheet for wattage specifications. |
| Speed adjust does not function | Analog input A06 is supported with Doosan, GM, and Volvo engines only | Check calibration values |
| Starts hard | Controller fuse blown | Replace the blown controller fuse. If the fuse blows again, troubleshoot the controller. |
| Stops suddenly | High water temperature switch inoperative | Replace the inoperative switch. |
| Voltage adjust does not function for paralleling applications | Analog input A07 description does not match Analog Volt Adjust | Change description to Analog Volt Adjust using Monitor III software or enable analog voltage adjust in Menu 11 |
Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.