Cummins/Onan Kt19 troubleshooting: 14 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan Kt19 — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Symptom | Cause | Remedy |
|---|---|---|
| Engine Will Not Crank or Cranks Slowly (Air Starter) | Incorrect Oil For Operating Conditions | Change oil and filters. Use recommended type (15W-40). |
| Engine Will Not Crank or Cranks Slowly (Electric Starter) | Incorrect Oil | Change oil and filters. Use recommended type (15W-40). |
| Engine Hard to Start or Will Not Start (Exhaust Smoke Present) | Engine Cranking Speed Low (Below 150 RPM) | Check engine starting system. |
| Engine Cranks But Will Not Start (No Smoke From Exhaust) | No Fuel In Tank | Add fuel. |
| Engine Starts But Will Not Keep Running | Air In The Fuel System | Check for air in fuel, tighten fuel connections, tighten filter, check fuel tank stand pipe. |
| Engine Will Not Shut Off | Fuel Pump Manual Override Open. | Check to make sure manual override screw is out to maximum travel. |
| Lubricating Oil Pressure Low | Incorrect Oil Level | Check for oil leaks. Add or drain engine oil. Check dipstick calibration. |
| Radiator Shutters are not Opening Completely or Cold Weather Radiator Cover Closed | Inspect the shutters. Repair or replace if necessary. Open radiator cover. | |
| Coolant Temperature Below Normal | Radiator Shutters Stuck in Open Position or Opening Early | Inspect the shutters. Repair or replace if necessary. |
| Coolant Temperature Above Normal | Low Coolant Level; Air Trapped in Cooling System; Plugged Heat Exchanger; Plugged Cooling Passages in Cylinder Head, Head Gasket, or Cylinder Block; Malfunctioning Keel Cooler | Add coolant.; Vent the cooling system to remove air.; Check/replace heat exchanger.; Flush the cooling system; fill with new coolant.; Refer to vessel manufacturer's service instructions. |
| Exhaust Smoke Excessive Under Load | Intake Air System Restricted; Intake Air Leaks Between Turbo-charger and Cylinder Head; Fuel Specifications Wrong; Valves or Injector Adjusted Wrong | Check intake air system for restrictions.; Check for air leaks.; Check fuel specifications.; Check/adjust valves or injectors. |
| Engine Power Output Low | Excessive Load for Engine Horsepower Rating; Low Power Due to Altitude; Fuel Suction Line or Fuel Filter Restricted; Lubricating Oil Level Too High; Throttle Linkage Adjustment Wrong; Intake or Exhaust System Restricted; Air in Fuel - Spongy Throttle; Fuel Drain Line Restricted or Fuel Tank Vents Plugged | Reduce vehicle load.; Derate engine above 3600 meters altitude.; Check fuel line for restriction. Replace fuel filter.; Check dipstick calibration and off pan capacity.; Check throttie linkage adjustment for full opening of throttle lever.; Check intake and exhaust systems for restrictions.; Check for air in fuet, tighten fuel connections and filter, check fuel tank stand pipe.; Check fuel drain line for toops, crimps or clamped points. Remove, clean, or replace venis. |
| Engine Will Not Reach Rated Speed When Loaded | Excessive Load for Engine Horsepower Rating; Tachometer Has a Malfunction; Throttle Linkage Adjustment Wrong; Fuel Suction Line Restricted | Reduce vehicle load or use lower gear.; Check with hand or digital tachometer.; Check for full throttle travel.; Check fuel inlet for restriction. |
| White Smoke or Rough Running At Idle (After Warmup Period) | Low Coolant Temperature | Refer to “Coolant Temperature Below Normal” chart. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Incorrect Oil For Operating Conditions. See the table for the matching fixes.
Documented causes: Incorrect Oil. See the table for the matching fixes.
Documented causes: Engine Cranking Speed Low (Below 150 RPM). See the table for the matching fixes.