Kohler 4CKM troubleshooting: 2 fault codes and 323 symptom-cause-remedy entries from the manufacturer's own service documentation.
Kohler 4CKM — full specs, parts & maintenance.
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| TP-5393 | Will not crank | Weak or dead battery, 15-amp controller fuse blown, Defective start switch, Remote start cable disconnected, Defective starter solenoid, Battery connections made in reverse | Recharge or replace, Replace fuse, Replace, Reconnect, Replace, Correct |
| LOP | Low Oil Pressure Shutdown |
| Symptom | Cause | Remedy |
|---|---|---|
| Will not crank | Weak or dead battery | Recharge or replace |
| Will not crank | 15-amp controller fuse blown | Replace fuse |
| Will not crank | Defective start switch | Replace |
| Will not crank | Remote start cable disconnected | Reconnect |
| Will not crank | Defective starter solenoid | Replace |
| Will not crank | Battery connections made in reverse | Correct |
| Will not start | Out of fuel | Replenish |
| Will not start | Clogged fuel filter | Replace |
| Will not start | Air cleaner clogged | Clean or replace |
| Will not start | Faulty spark plug | Replace or regap spark plugs |
| Will not start | Shorted or open ignition coil | Replace |
| Will not start | Faulty ground | Clean and retighten |
| Will not start | Loose spark plug wire connection | Reconnect and/or tighten |
| Will not start | Weak or dead battery | Recharge or replace |
| Will not start | Choke adjustment wrong | Adjust |
| Will not start | Low oil pressure (LOP) shutdown | Correct cause of shutdown |
| Hard starting | Stale or bad fuel | Replace |
| Hard starting | Air cleaner clogged | Clean or replace element |
| Hard starting | Carburetor adjustment wrong | Adjust |
| Hard starting | Faulty spark plug | Replace or regap spark plugs |
| Hard starting | Weak ignition coil | Replace |
| Hard starting | Improper cooling | Inspect cooling system |
| Hard starting | Choke adjustment wrong | Adjust |
| Stops suddenly | Out of fuel | Replenish |
| Stops suddenly | Air cleaner clogged | Clean or replace element |
| Stops suddenly | Faulty spark plug | Replace or regap spark plugs |
| Stops suddenly | Low oil pressure | Check oil level |
| Stops suddenly | Controller voltage supply fuse blown | Replace fuse |
| Stops suddenly | De-icing module fuse blown (gasoline models) | Replace fuse |
| Stops suddenly | Defective de-icing module (gasoline models) | Have unit serviced by an authorized Kohler service dealer/distributor |
| Lacks power | Air cleaner clogged | Clean or replace element |
| Lacks power | Improper cooling | Inspect cooling system |
| Lacks power | Engine overload | Reduce load |
| Lacks power | Bad or stale fuel | Replace |
| Lacks power | Faulty spark plug | Replace or regap spark plugs |
| Lacks power | Carburetor adjustment wrong | Adjust |
| Lacks power | Carbon build-up | Have unit serviced by an authorized Kohler service dealer/distributor |
| Lacks power | Governor not properly adjusted or defective | Have unit serviced by an authorized Kohler service dealer/distributor |
| Operates erratically | Air cleaner clogged | Clean or replace element |
| Operates erratically | Stale or bad fuel | Replace |
| Operates erratically | Faulty spark plug | Replace or regap spark plugs |
| Operates erratically | Carburetor adjustment wrong | Adjust |
| Operates erratically | Governor not properly adjusted or defective | Have unit serviced by an authorized Kohler service dealer/distributor |
| Overheats | Improper cooling | Check intake and outlet openings |
| Overheats | Air cleaner clogged | Clean or replace element |
| Overheats | Carburetor adjustment too lean | Adjust |
| No AC output | Circuit breaker in OFF Position | Reset to ON position |
| No AC output | AC Circuit breaker tripping due to overload on generator set | Reduce load (see Wattage Requirements) |
| No AC output | Short circuit in vehicle circuit causing breaker to trip | Reset— if it trips repeatedly, stop set and contact service center |
| No AC output | General malfunction such as faulty component or other internal fault | Contact generator service dealer/distributor for repairs |
| Low output or excessive drop in voltage | Engine speed too low | Contact generator service dealer/distributor for repairs |
| Low output or excessive drop in voltage | Generator overloaded | Reduce load |
| Low output or excessive drop in voltage | Voltage regulator adjustment | Contact generator service dealer/distributor |
| No battery charging output (if equipped) | Defective battery charging alternator | Contact generator service dealer/distributor |
| Will not crank (dead) | Controller 15-amp supply fuse blown | Replace fuse. If fuse failure continues, replace fuse and troubleshoot DC circuit and wiring. |
| Will not crank (dead) | Battery disconnected or improperly connected | Check connections |
| Will not crank (dead) | Dead battery | Check electrolyte level and specific gravity (batteries with filler caps only). Perform load test |
| Will not crank (dead) | Corroded or loose battery connections | Clean or replace battery connections |
| Will not crank (dead) | Open wiring, terminal, pin, foil, etc. | Check continuity |
| Will not crank (dead) | Defective starter | Service or replace |
| Will not crank (dead) | Defective starter solenoid | Check continuity of circuit. Bypass solenoid using jumper wire. If starter cranks, replace solenoid. |
| Will not crank (dead) | Defective start/stop switch | Check continuity |
| Will not crank (dead) | Defective K2 or K3 | Check/replace defective relay |
| Will not crank (dead) | Defective remote start/stop switch | If start/stop switch on controller functions, replace or repair remote switch and/or wiring. |
| Will not start (cranks okay) | No fuel in tank | Replenish |
| Will not start (cranks okay) | Air cleaner clogged | Clean or replace element |
| Will not start (cranks okay) | Defective fuel solenoid | Check continuity |
| Will not start (cranks okay) | Defective fuel pump (gasoline fuel only) | Verify operation with 12 volts DC applied. Check fuel pressure is 2-3.5 psi (14-24 kPa). |
| Will not start (cranks okay) | Clogged fuel filter | Replace filter |
| Will not start (cranks okay) | Water, dirt in fuel system | Drain, flush fuel system |
| Will not start (cranks okay) | Defective antidieseling solenoid | Check operation |
| Will not start (cranks okay) | Carburetor adjustment wrong | Adjust carburetor |
| Will not start (cranks okay) | Defective/misadjusted spark plug(s) | Regap or replace |
| Will not start (cranks okay) | Loose spark plug wires | Reconnect wires |
| Will not start (cranks okay) | Defective ignition module | Test. If defective, replace |
| Will not start (cranks okay) | Electronic governor overspeed setting too low | Adjust electronic governor |
| Will not start (cranks okay) | Engine malfunction | Troubleshoot engine |
| Will not start (cranks okay) | Open wiring, terminal, or pin (P2 connector) | Check continuity |
| Will not start (cranks okay) | K4 relay contact(s) defective | Check relay contact continuity |
| Will not start (cranks okay) | K2 (normally closed) defective relay contact | Check relay contact continuity |
| Will not start (cranks okay) | K3 relay defective (K2 relay must be energized for K3 to function) | Check relay coil continuity |
| Will not start (cranks okay) (continued) | K5 contact defective | Check relay contact continuity. |
| Will not start (cranks okay) (continued) | Weak battery | Recharge battery. Check electrolyte level and specific gravity (batteries with filler caps only). Perform load test, or replace battery. |
| Will not start (cranks okay) (continued) | Fuse blown on voltage regulator circuit | Replace fuse |
| Will not start (cranks okay) (continued) | Defective gas valve (LP fuel only) | Test. If defective, replace |
| Engine starts, but stops after start switch is released | Incorrect generator output voltage | Check AC output voltage. |
| Engine starts, but stops after start switch is released | Open wiring (P1 or P2 connector) | Check continuity |
| Engine starts, but stops after start switch is released | K1 relay coil defective | Check continuity. If LED1 is not lit, K1 relay is not receiving power from stator B1/B2 winding |
| Engine starts, but stops after start switch is released | No/low oil pressure | Check oil level, oil pressure, oil pump, and low oil pressure shutdown switch |
| Engine starts, but stops after start switch is released | Defective low oil pressure switch | Disconnect lead from low oil pressure switch and isolate the lead from ground. If engine starts and continues to run, replace low oil pressure switch. LOP switch contacts close at approx. 3.5 psi (24 kPa). NOTE: Verify pressure before replacing switch. |
| Hard starting | Fuel vapor lock (hot engine only) | Check fuel line routing |
| Hard starting | Choke out of adjustment | Repair/replace |
| Hard starting | Defective ignition module | Test and/or replace |
| Hard starting | Defective spark | Replace spark plugs |
| Hard starting | Worn piston rings, valves, etc. | Check compression and oil consumption |
| Hard starting | Improper cooling (hot engine only) | Check air flow cooling system |
| Hard starting | Defective anti-icing plate (thermistor) | Test and/or repair |
| Generator set shuts down by itself | No fuel in tank | Replenish |
| Generator set shuts down by itself | Fuel line restriction | Inspect fuel lines and tank |
| Generator set shuts down by itself | Clogged fuel filter | Replace filter |
| Generator set shuts down by itself | Defective fuel pump (gasoline fuel only) | Verify operation with 12 VDC applied. Check fuel pressure is 2-3.5 psi (14-24 kPa) |
| Generator set shuts down by itself | Engine overloaded | Reduce electrical load |
| Generator set shuts down by itself | Engine overheated (hot engine only) | Check air intake, carburetor adjustment, oil level, etc. |
| Generator set shuts down by itself | Loss of generator output voltage to K1 relay (LED1 not lit) | Check AC voltage at B1/B2 winding; Check continuity of B1/B2 stator leads |
| Generator set shuts down by itself | Air cleaner clogged | Clean or replace element |
| Generator set shuts down by itself | Fuel vapor lock (hot engine only) | Reroute fuel lines away from heat source (exhaust system) |
| Generator set shuts down by itself | Faulty carburetor shutdown solenoid | Replace solenoid |
| Generator set shuts down by itself | Faulty spark plug(s) | Replace spark plug(s) |
| Generator set shuts down by itself | Defective ignition module | Test and/or replace |
| Generator set shuts down by itself | Deicing module fuse blown (gasoline models) | Replace fuse |
| Generator set shuts down by itself (continued) | No/low oil pressure | Check oil level, oil pressure, oil pump, and low oil pressure shutdown switch |
| Generator set shuts down by itself (continued) | Defective low oil pressure switch | Disconnect lead from low oil pressure switch and isolate the lead from ground. If engine starts and continues to run, replace low oil pressure switch. LOP switch contacts close at approx. 3.5 psi (24 kPa). NOTE: Verify pressure before replacing switch. |
| Generator set shuts down by itself (continued) | Carburetor icing problem | Check/repair manual or automatic deicing system as applicable. |
| Generator set shuts down by itself (continued) | Controller fuse blown | Replace fuse |
| Will not carry load or runs rough | Excessive load connected to generator | Reduce electrical load |
| Will not carry load or runs rough | Improper cooling (hot engine only) | Check air flow cooling system |
| Will not carry load or runs rough | Governor not properly adjusted or defective (Engine not operating at rated rpm) | Check speed using tachometer or frequency meter. NOTE: For 60 Hz-1800 RPM For 50 Hz-1500 RPM |
| Will not carry load or runs rough | Engine in need of overhaul | Contact authorized Kohler dealer/distributor |
| Will not carry load or runs rough (continued) | Fuel line restriction | Inspect fuel lines and tank. |
| Will not carry load or runs rough (continued) | Vent in fuel tank cap obstructed (gasoline fuel) | Clean cap in solvent, blow dry |
| Will not carry load or runs rough (continued) | Dirty fuel filter (gasoline fuel only) | Replace fuel filter |
| Will not carry load or runs rough (continued) | Improper type of fuel | Use specified type of fuel; consult fuel supplier |
| Will not carry load or runs rough (continued) | Defective fuel pump | Check fuel pump pressure is 2-3.5 psi (14-24 kPa) |
| Will not carry load or runs rough (continued) | Governor not properly adjusted or defective (Engine not operating at rated rpm) | Check speed using tachometer or frequency meter. NOTE: Hz x 120/ No. of rotor poles=rpm (Example: 60 x 120/4=1800) |
| Will not carry load or runs rough (continued) | Carburetor not adjusted or defective | Check and/or adjust |
| Will not carry load or runs rough (continued) | Defective ignition module | Test and/or replace |
| Will not carry load or runs rough (continued) | Defective/misadjusted spark plug | Regap or replace |
| Will not carry load or runs rough (continued) | Carburetor choke | Test and/or replace |
| Will not carry load or runs rough (continued) | Fuel leak | Tighten fittings |
| Will not carry load or runs rough (continued) | Valves not sealing | Compression test |
| Will not carry load or runs rough (continued) | Improper valve clearance | Adjust proper valve clearance |
| Will not carry load or runs rough (continued) | Excessive carbon buildup | Clean cylinder head |
| Will not carry load or runs rough (continued) | Fuel vapor lock (hot engine only) | Reroute fuel lines away from heat. |
| Lacks power | Governor not properly adjusted or defective (Engine not operating at rated RPM) | Check engine speed using frequency meter or tachometer. NOTE: For 60 Hz-1800 RPM For 50 Hz-1500 RPM |
| Lacks power | Engine overloaded | Reduce electrical load |
| Lacks power | Stale or bad fuel | Replace |
| Lacks power | Fuel line restriction | Check fuel lines and tank |
| Lacks power | Dirty fuel filter (gasoline fuel only) | Replace fuel filter |
| Lacks power | Choke misadjusted or defective | Check and/or adjust |
| Lacks power | Carbon buildup | Clean cylinder heads |
| Lacks power | Faulty spark plug(s) | Replace spark plug(s) |
| Lacks power | Defective ignition module | Test and/or replace coil |
| Overheats | Improper cooling system | Check cooling air flow |
| Overheats | Carburetor adjusted too lean | Adjust carburetor |
| Overheats | Faulty spark plug(s) | Replace spark plug(s) |
| Overheats | Carburetor adjustment wrong | Adjust carburetor |
| Operates erratically | Governor not properly adjusted or defective (Engine not operating at rated RPM) | Check engine speed using frequency meter or tachometer NOTE: For 60 Hz-1800 RPM For 50 Hz-1500 RPM |
| Operates erratically | Fuel line restriction | Inspect fuel lines and tank. Check fuel pump pressure of 2-3.5 psi (14-24 kPa) |
| Operates erratically | Faulty spark plug(s) | Replace spark plug(s) |
| Unit is noisy | Exhaust system leak | Check and replace as necessary |
| Unit is noisy | Broken or damaged vibromounts | Check and replace as necessary |
| Unit is noisy | Loose or vibrating sheet metal/housing | Retighten screws |
| Unit is noisy | Inadequate compartment clearances | Check clearances |
| Unit is noisy | Exhaust piping or air inlets/outlets not securely installed | Inspect for loose parts |
| Unit is noisy | No compartment sound insulation | Install fireproof insulation |
| Unit is noisy | Excessive vibration—engine/generator | Check rotor, crankshaft, bearing, etc. (Disassembly of engine and/or generator may be required); Contact authorized Kohler dealer/distributor |
| Battery will not charge or goes dead | Loose or corroded connections | Clean and tighten connections |
| Battery will not charge or goes dead | Sulfated or damaged battery | Check electrolyte level and specific gravity (batteries with filler caps only) |
| Battery will not charge or goes dead | Defective battery charging circuit | Check battery charging circuit |
| Starter does not work properly | Loose or corroded connections | Clean and tighten loose connections |
| Starter does not work properly | Low battery output | Check electrolyte level and specific gravity (batteries with filler caps only) |
| Starter does not work properly | Defective starter solenoid | Check starter solenoid. Replace starter solenoid, as necessary |
| Starter does not work properly | Defective start/stop switch | Replace switch |
| Starter does not work properly | Defective wiring | Check wiring |
| Starter does not work properly | Defective starter | Replace starter |
| Starter cranks slowly | Low battery output | Check electrolyte level and specific gravity (batteries with filler caps only) |
| Starter cranks slowly | Too heavy viscosity lube oil | Use specified viscosity oil |
| Starter cranks slowly | Loose or corroded wiring | Clean and tighten loose connections |
| Starter cranks slowly | High starter current draw | Repair/Replace starter |
| Starter cranks slowly | Battery cable undersize | Select specified size cable |
| No generator output voltage | AC output circuit breaker open or defective | Check position of circuit breaker. Check AC voltage on generator side of circuit breakers |
| No generator output voltage | AC circuit breaker tripping due to overload on unit | Reduce load. Reset and attempt startup |
| No generator output voltage | Short circuit in vehicle wiring causing circuit breaker to trip | Reset circuit breaker. If breaker trips again, check wiring. |
| No generator output voltage | Transfer switch in off or other power position | Reset |
| No generator output voltage | No battery voltage to field during cranking | Check flashing current |
| No generator output voltage | Open flashing diode (D4 or D7) | Check for open or shorted diode (a good diode has high resistance one way and low resistance the other way when tested with ohmmeter) |
| No generator output voltage | K1 relay (normally closed) contacts open | Check continuity |
| No generator output voltage | Open wire or pin in flashing current circuit | Check continuity |
| No generator output voltage | Defective rotor (open, grounded, or shorted windings) | Test and/or replace |
| No generator output voltage | Defective stator (open, grounded, or shorted windings) | Test and/or replace |
| No generator output voltage | Brushes sticking in holder | Check alignment |
| No generator output voltage (continued) | Missing brush spring | Check condition |
| No generator output voltage (continued) | Fuse blown in voltage regulator circuit (lead 55) | Replace fuse. If fuse blows again, check voltage regulator and stator windings |
| No generator output voltage (continued) | Rotor slip rings dirty or corroded | Check and/or service |
| No generator output voltage (continued) | Broken, weak, or missing brush spring | Check condition |
| No generator output voltage (continued) | Set overloaded | Make sure capacity is not being exceeded |
| No generator output voltage (continued) | Defective rotor | Test and/or replace |
| No generator output voltage (continued) | Defective stator | Test and/or replace |
| No generator output voltage (continued) | Defective voltage regulator | Test and/or replace |
| No generator output voltage (continued) | Improperly adjusted voltage regulator | Readjust |
| No generator output voltage (continued) | Defective voltage regulator. Misadjusted voltage regulator | Excite rotor separately |
| Low generator output voltage | Low engine rpm | Check engine speed using frequency meter or tachometer. NOTE: For 60 Hz-1800 RPM For 50 Hz-1500 RPM |
| High generator output voltage | Defective voltage regulator | Test and/or replace |
| High generator output voltage | Voltage regulator misadjusted | Readjust |
| High generator output voltage | Open or poor splice connection at regulator sensing terminals on stator or poor pin connection at voltage regulator | Check continuity and clean connections |
| Engine does not run after start switch is released | Defective K4 relay | Replace circuit board (Defective K4 relay) |
| Engine does not run at stable speed | Stepper motor/electronic governor fault | Disconnect stepper motor from electronic governor and manually throttle engine |
| Engine does not run at constant, stable speed | Carburetor or engine problem | See engine manual |
| Engine does not run at constant, stable speed | Electronic governor gain out of adjustment | Adjust electronic governor gain. If set compensates for load changes too slowly (seeks), adjust gain control clockwise. If set compensates too quickly (hunts), adjust gain control counterclockwise |
| LED5 does not light after 5-10 seconds of running time | Defective K5 relay | Replace circuit board (K5 relay defective) |
| LED4 does not light | Defective K1 or K2 relay | Replace circuit board. (Defective K1 or K2 relay) |
| Local and remote start/stop switches do not function properly | Defective start/stop switch | Replace defective start/stop switch |
| Low oil pressure switch does not check out okay | Defective low oil pressure switch | Replace low oil pressure switch |
| Engine does not have oil pressure (use mechanical gauge) | Low oil level; faulty oil pump | Check oil level; Repair/replace oil pump |
| Engine does not continue to run after start switch is released | Defective K4 relay | Replace circuit board (K4 relay defective) |
| Engine cannot be stopped by using stop switch | Ignition module to circuit board lead disconnected | Correct wiring problem |
| Engine cannot be stopped by using stop switch | Defective K4 relay | Replace circuit board (K4 relay defective) |
| Engine cannot be stopped by using stop switch | Defective start/stop switch | Replace defective start/stop switch |
| No AC output when start button is held and unit is running | No battery voltage at brushes (check wiring) | Replace controller circuit board |
| No AC output when start button is held and unit is running | Other components defective | Separately excite generator set to determine if other components are defective |
| AC output voltage not at spec. (See Section 7, Separate Excitation) | Voltage regulator fault | Test voltage regulator |
| AC output voltage not at spec. (See Section 7, Separate Excitation) | Stator, rotor, or brushes fault | Test stator, rotor, and brushes |
| AC output not at proper voltage (e.g. 120 volts AC) | Stator, rotor, or brushes fault | Test stator, rotor, and brushes |
| No 12 vac output at B1/B2 stator winding | Voltage regulator fuse blown | Replace fuse |
| No 12 vac output at B1/B2 stator winding | Voltage regulator out of adjustment | Test/adjust voltage regulator |
| Engine does not crank | Battery not fully charged or not connected | See Battery Section |
| Engine does not crank | 15-amp fuse blown | Replace fuse. See Controller Troubleshooting Steps A-C on page 6-15 |
| Engine does not crank | No 12 vdc present across wires 71 and N on the starter solenoid during cranking | See Controller Troubleshooting Steps A-J on pages 6-15 and 6-16 |
| Engine does not crank | No 12 vdc present across both large contacts of the starter solenoid to ground during cranking | Replace the starter solenoid |
| Engine does not crank | Starter cable or starter motor fault | Check the starter cable or replace the starter motor |
| Engine cranks but will not start | Insufficient supply of fuel at the carburetor | See Fuel System |
| Engine cranks but will not start | No spark at both spark plugs (both spark plug leads must be connected) | See Ignition System |
| Engine cranks but will not start | Throttle plate does not open fully | See Governor System |
| Engine cranks but will not start | Air intake restricted | See Air Cleaner System |
| Engine cranks but will not start | Preliminary adjustment not made correctly to the carburetor or antidiesel solenoid not energized (solenoid not being pulled in) | See Carburetor System |
| Engine cranks but will not start | Internal problem with the engine | Troubleshoot with the Engine Service Manual (TP-2204) |
| Engine starts but stops after the start switch is released | No rated AC output voltage | See Generator Alternator System |
| Engine starts but stops after the start switch is released | Oil pressure not within the operating range | See Engine Service Manual (TP-2204) |
| Engine starts but stops after the start switch is released | Generator B1 and B2 leads do not produce 12-15 vac | See Generator Alternator System |
| Engine starts but stops after the start switch is released | Controller fault | See Controller Troubleshooting Steps Q-X on pages 6-17 and 6-18 |
| Engine difficult to start | Fuel stale or contaminated | See Fuel System |
| Engine difficult to start | Air intake restricted | See Air Cleaner System |
| Engine difficult to start | Carburetor or choke out of adjustment | See Carburetor System |
| Engine difficult to start | Insufficient ignition spark | See Ignition System |
| Engine difficult to start | Engine problem | See Engine Service Manual (TP-2204) |
| Engine hunts or misses | Engine not receiving sufficient amount of fuel from the fuel pump | See Fuel System |
| Engine hunts or misses | No spark at both cylinders | See Ignition System |
| Engine hunts or misses | Carburetor out of adjustment | See Carburetor System |
| Engine hunts or misses | Governor out of adjustment | See Governor System |
| Engine hunts or misses | Engine problem | See Engine Service Manual (TP-2204) |
| Generator battery dead or low | Battery not in good condition or connections not clean | See Battery System |
| Generator battery dead or low | Battery-charging voltage regulator electrically grounded | Ground battery-charging voltage regulator |
| Generator battery dead or low | Stator fault | See Section 7—Stator |
| Generator shuts off by itself | Unit loses AC output before unit shuts down | See Section 7 |
| Generator shuts off by itself | Unit loses spark to the cylinders | See Ignition System |
| Generator shuts off by itself | Unit loses fuel or fuel depleted | See Fuel System |
| Generator shuts off by itself | Unit overspeeds | See Governor System |
| Generator shuts off by itself | Controller fault | See Controller Troubleshooting Steps Y-BB on pages 6-18 and 6-19 |
| Engine cannot be stopped by using the stop switch | Unit does not stop if you ground wire #72 from the ignition module | See Ignition System |
| Engine cannot be stopped by using the stop switch | Unit does not stop if you remove the AD wire from the antidiesel solenoid | See Carburetor System and Controller Troubleshooting steps Y-BB on pages 6-18 and 6-19 |
| Engine cannot be stopped by using the stop switch | Controller fault | See Controller Troubleshooting steps Y-BB on pages 6-18 and 6-19 |
| No 12 vdc at P4-14 | Wire P to starter solenoid or battery positive connections | Check wire P to starter solenoid. Check battery positive connections |
| No 12 vdc at P1-14 | Controller fuse | Check controller fuse |
| Controller case does not have a battery ground | Controller not grounded to frame or battery negative connections | Reground controller to frame. Check battery negative connections |
| P1-9 not grounded | N wire to ground stud in controller | Check N wire to ground stud in controller |
| LED2 does not light up when start switch is pushed | Start/stop switch fault | Ground Pin P2-4. Does LED2 light up? If yes, replace start/stop switch |
| LED3 does not light up | Control board fault | Replace control board |
| No 12 vdc at P1-4 while trying to start | Control board fault | Replace control board |
| No 12 vdc at P4-4 | Wire #71 to control board | Check wire #71 to control board |
| No 12 vdc present across P1-5(+) to P1-12(-) while the unit is cranking | Control board fault | Replace control board |
| No 12 vdc present across P4-5(+) to P4-12(-) | Plug connections and wires FN and FP | Check plug connections and wires FN and FP |
| No 12 vdc present at P1-1 when the start switch is pressed | Control board fault | Replace control board |
| No 12 vdc present at P4-8 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| P4-18 not battery grounded | Wire N in the controller | Check wire N in the controller |
| No 12 vdc present at P1-8 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| LED4 does not light up | Control board fault | Replace control board |
| No 12 vdc present at P5-2 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| P5-1 is not a good battery ground | Wire N in the controller | Check wire N in the controller |
| No 12-16 vac present across P4-3 and P4-6 when the start switch is depressed and the unit is running | Wires B1 and B2 routed to the alternator | Check wires B1 and B2 routed to the alternator |
| P1-3 and P1-6 do not have 12-16 vac across them with the unit running and the start switch depressed | Wires B1 and B2 in the controller | Check wires B1 and B2 in the controller |
| LED1 does not light up with the engine running and the start switch depressed | Control board fault | Replace control board |
| LED5 does not light up approximately 7 seconds after LED1 lights | Control board fault | Replace control board |
| Unit does not continue to run if the start switch is released | Control board fault | Replace control board |
| No 12 vdc at P2-3 | Control board fault | Replace control board |
| No 12 vdc at P3-6 | Wire #70 in the controller | Check wire #70 in the controller |
| LED4 lights when the unit is running and shuts down the unit | Low oil pressure switch or engine oil pressure | Remove wire #13. If the unit continues to run, check the low oil pressure switch and the engine oil pressure |
| LED4 lights when the unit is running and shuts down the unit | Stop switch or generator voltage regulator | Check stop switch and the generator voltage regulator |
| Unit does not stop when the stop switch is depressed | P2-5 not a good battery ground with the stop switch depressed | Check continuity from P2-5 to Stop switch #43 terminal. If good, depress Stop switch and check continuity from 43 to N. If continuity is bad, replace Start/Stop switch |
| Unit does not stop when the stop switch is depressed | P1-7 not a good battery ground with the stop switch depressed | Replace control board |
| Unit does not stop when the stop switch is depressed | P4-7 not a good battery ground with the stop switch depressed | Check wire #72 in the controller |
| Unit does not stop when the stop switch is depressed | Ignition module fault | Replace the ignition module (TP-2204) |
| No- or low-AC output | Faulty voltage regulator | Check the condition of the voltage regulator 5- or 10-amp fuse; if good, separately excite the generator to determine the presence of a faulty voltage regulator |
| No- or low-AC output | Running fault in the rotor and/or stator | Separately excite the generator to determine if a running fault exists in the rotor and/or stator |
| Engine does not run at stable speed | Stepper motor/electronic governor; carburetor or engine problem | Disconnect stepper motor from electronic governor and manually throttle engine; see engine manual |
| Engine does not have oil pressure (use mechanical gauge) | Low oil level; defective oil pump | Check oil level; repair/replace oil pump |
| Engine continues to run after start switch is released | Defective K4 relay | Replace circuit board (K4 relay defective) |
| AC output voltage not at spec. | Voltage regulator; stator, rotor, and brushes | Test voltage regulator; test stator, rotor, and brushes |
| AC output not at proper voltage (e.g. 120 volts AC) | Stator, rotor, and brushes | Test stator, rotor, and brushes |
| No 12 vac output at B1/B2 stator winding | Voltage regulator fuse; stator, rotor, and brushes | Replace controller circuit board; test stator, rotor, and brushes |
| Voltage regulator fuse not okay | Blown fuse | Replace fuse |
| Voltage regulator fuse okay but no output | Voltage regulator out of adjustment | Test/adjust voltage regulator |
| Engine does not crank | Battery not fully charged and connected | See Battery Section |
| Engine does not crank | Starter cable or starter motor | Check the starter cable or replace the starter motor |
| Engine starts but stops after the start switch is released | Generator does not have rated AC output voltage | See Generator Alternator System |
| Engine starts but stops after the start switch is released | Controller | See Controller Troubleshooting Steps Q-X on pages 6-17 and 6-18 |
| Generator battery dead or low | Stator | See Section 7—Stator |
| Generator shuts off by itself | Controller | See Controller Troubleshooting Steps Y-BB on pages 6-18 and 6-19 |
| Engine cannot be stopped by using the stop switch | Controller | See Controller Troubleshooting steps Y-BB on pages 6-18 and 6-19 |
| No 12 vdc at P4-14 | Wire P to starter solenoid; battery positive connections | Check wire P to starter solenoid; check battery positive connections |
| Controller case does not have a battery ground | Battery negative connections | Reground controller to frame; check battery negative connections |
| LED2 does not light up when start switch is pushed | Start/stop switch | Ground Pin P2-4. Does LED2 light up? If yes, replace start/stop switch |
| LED3 does not light up | Control board | Replace control board |
| No 12 vdc at P1-4 while trying to start | Control board | Replace control board |
| While the unit is cranking, 12 vdc not present across P1-5(+) to P1-12(-) | Control board | Replace control board |
| 12 vdc not present across P4-5(+) to P4-12(-) | Plug connections and wires FN and FP | Check plug connections and wires FN and FP |
| No 12 vdc at P1-1 when the start switch is pressed | Control board | Replace control board |
| No 12 vdc at P4-8 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| No 12 vdc at P1-8 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| LED4 does not light up | Control board | Replace control board |
| No 12 vdc at P5-2 when the start switch is pressed | Wire #70 in the controller | Check wire #70 in the controller |
| P5-1 not a good battery ground | Wire N in the controller | Check wire N in the controller |
| No 12-16 vac across P4-3 and P4-6 when the start switch is depressed and the unit is running | Wires B1 and B2 routed to the alternator | Check wires B1 and B2 routed to the alternator |
| LED1 does not light up with the engine running and the start switch depressed | Control board | Replace control board |
| LED5 does not light up approximately 7 seconds after LED1 lights | Control board | Replace control board |
| Unit does not continue to run if the start switch is released | Control board | Replace control board |
| No 12 vdc at P2-3 | Control board | Replace control board |
| LED4 lights when the unit is running and shuts down the unit | Low oil pressure switch and the engine oil pressure | Remove wire #13. Does the unit continue to run? If yes, check the low oil pressure switch and the engine oil pressure |
| LED4 lights when the unit is running and shuts down the unit | Stop switch and the generator voltage regulator | Check stop switch and the generator voltage regulator |
| Unit does not stop when the stop switch is depressed | Controller | See Step Z |
| P2-5 not a good battery ground with the stop switch depressed | Continuity from P2-5 to Stop switch #43 terminal or from 43 to N | Check continuity from P2-5 to Stop switch #43 terminal. If good, depress Stop switch and check continuity from 43 to N. If continuity is bad, replace Start/Stop switch |
| P1-7 not a good battery ground with the stop switch depressed | Control board | Replace control board |
| P4-7 not a good battery ground with the stop switch depressed | Wire #72 in the controller | Check wire #72 in the controller |
| P4-7 is a good battery ground with the stop switch depressed | Ignition module | Replace the ignition module (TP-2204) |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Air cleaner clogged; Improper cooling; Engine overload; Bad or stale fuel. See the table for the matching fixes.
Documented causes: No fuel in tank; Air cleaner clogged; Defective fuel solenoid; Defective fuel pump (gasoline fuel only). See the table for the matching fixes.
Documented causes: Fuel line restriction; Vent in fuel tank cap obstructed (gasoline fuel); Dirty fuel filter (gasoline fuel only); Improper type of fuel. See the table for the matching fixes.