Kohler 4.5 CKM troubleshooting: 12 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Kohler 4.5 CKM — full specs, parts & maintenance.
| Code | Meaning |
|---|---|
| P26 | Fuel Pump/Valve |
| P3-4 | SDR Relay |
| LOP | Low Oil Pressure |
| Symptom | Cause | Remedy |
|---|---|---|
| Will not start (cranks OK) | K2 relay coil defective, Engine defective (no compression, stuck valves, etc.), Defective LP gas valve or secondary regulator | Check continuity, Troubleshoot engine, Check LP gas pressure at secondary regulator. Pressure should be 4 to 6 oz. or 7 to 11 inches water column. |
| Engine starts, but does not continue to run after start switch is released | Open wiring (P1 or P2 connector), No engine oil pressure, Defective low oil pressure (LOP) shutdown switch, K1 relay coil defective, K1 relay (N.O.) contacts remain open | Check AC voltage, Check stator continuity, Check continuity, Check oil pressure and pump, Bypass LOP shutdown switch using jumper wire to ground. If engine continues to run after start switch is released, replace LOP shutdown switch. |
| No generator output voltage | Open wiring, terminal, or pin in build-up circuit (P1 connector), Open D1 or D2 diode, K1 relay (N.C.) contacts open (contacts between D2 and P3-4), Brushes sticking in holder, Rotor slip rings dirty or corroded | Check continuity, Check for open or shorted diode. (A good diode has high resistance one way and low resistance the other way, when tested with ohmmeter), Check continuity, Check alignment, Check and/or service |
| High generator output voltage | Open or poor splice connection at terminals 33-3 or 44-4 on stator (regulator sensing) | Check continuity |
| Low generator output voltage | Low engine rpm, Defective voltage regulator | Check speed using tachometer or frequency meter, Test and/or replace |
| Generator set shuts down by itself | No fuel in tank, Fuel line restriction, Dirty electric fuel pump filter (gasoline model only), Fuel line drawing air, Defective electric fuel pump (gasoline model only), Engine overloaded, Engine overheated, Low engine oil pressure, Ignition coil fails when hot, Fuel vapor lock | Replenish, Check fuel lines and tank. Check gasoline fuel pressure of 4.5 psi (31 kPa), Clean filter, Check fuel lines and tank, Check fuel pressure of 4.5 psi (31 kPa), Reduce electrical load, Check air intake, carburetor adjustment, oil level, timing, etc., Check pressure and pump components, Check using “cold” test |
| Generator set shut down by itself (cont.) | Loss of generator output voltage to K1 relay | Check AC voltage at rectifier, Check continuity of B1 & B2 stator leads |
| Generator set will not carry load or runs rough | Excessive load connected to generator, Engine not operating at rated rpm, Governor not properly adjusted or defective, Carburetor not properly adjusted or defective (gasoline model only), Carburetor not properly adjusted or defective (LP gas model only), Defective or grounded breaker points, Improper timing, Defective ignition coil, Defective or misadjusted spark plug, Carburetor choke mis-adjusted or defective (gasoline model only), Fuel line restriction | Reduce electrical load, Check speed using tachometer or frequency meter, NOTE: Hz x 120 = rpm x no. of rotor poles, Check speed using tachometer or frequency meter, NOTE: Hz x 120 = rpm x no. of rotor poles, Check and/or service |
| Low oil pressure | Will cause (LOP) switch contacts to open and de-energize K1 relay. | None provided in the text. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: K2 relay coil defective, Engine defective (no compression, stuck valves, etc.), Defective LP gas valve or secondary regulator. See the table for the matching fixes.
Documented causes: Open wiring (P1 or P2 connector), No engine oil pressure, Defective low oil pressure (LOP) shutdown switch, K1 relay coil defective, K1 relay (N.O.) contacts remain open. See the table for the matching fixes.
Documented causes: Open wiring, terminal, or pin in build-up circuit (P1 connector), Open D1 or D2 diode, K1 relay (N.C.) contacts open (contacts between D2 and P3-4), Brushes sticking in holder, Rotor slip rings dirty or corroded. See the table for the matching fixes.