Northern Lights M20C troubleshooting: 18 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Northern Lights M20C — full specs, parts & maintenance.
| Symptom | Cause | Remedy |
|---|---|---|
| Engine temperature above 205°F (96°C) | Shut off the engine immediately | |
| Oil pressure below normal levels | Check oil pressure gauge; shut down if it does not show a normal reading after a few seconds of operation | |
| Low crankcase oil level | Fill with recommended lubricating oil and restart; watch the oil pressure gauge carefully | |
| Temperature rises above 205°F (96°C) on Marine units | Repeat troubleshooting | |
| Shutdown is activated and the temperature gauge shows temperature within normal temperature range | A. Check the engine crankcase oil level b. If the oil level is low, fill with recommended lubricating oil and restart. Watch the oil pressure gauge carefully and shut off the engine if it does not show a normal reading (20-60 PSI) after a few seconds of operation. c. If the oil level is normal, DO NOT restart the engine. Call your dealer for assistance. | |
| Battery will not charge | Loose or corroded connections, Sulfated or worn out batteries | Clean and tighten battery connections, Check specific gravity of each battery, Check electrolyte level of each battery |
| Starter inoperative | Loose or corroded connections | Clean and tighten loose battery and harness plug connection |
| Low battery output | Sulfated or worn out batteries, Loose or defective electrical system ground wire | Check specific gravity of each battery, Check electrolyte level of each battery, Repair or replace |
| Starter cranks slowly | Batteries too small, Battery cables too small, Crankcase oil too heavy | Check specific gravity of each battery, Replace battery if necessary, Check electrolyte level of each battery, If low, fill cells with distilled water, Fill with oil of appropriate viscosity |
| Entire electrical system does not function | Faulty connection, Sulfated or worn out batteries | Clean and tighten battery and harness plug connections, Check specific gravity and electrolyte level of each battery |
| Engine hard to start or will not start | Improper starting procedure, No fuel, Low battery output, Excessive resistance in starting circuit, Crankcase oil too heavy, Improper type of fuel, Water, dirt or air in fuel system, Clogged primary fuel filter element, Clogged secondary fuel filter element, Dirty or faulty injection nozzles | See starting section of this manual. Take special note of Bypass Switch operation, Check level of fuel in fuel tank, Check electrolyte level and condition, Clean and tighten all battery connections, Use oil of proper viscosity, Consult fuel supplier and use proper type of fuel for operating condition, Drain, flush, fill and bleed system, Clean or replace filter element, Replace filter element, Have your dealer check injection nozzles |
| Engine runs irregularly or stalls frequently | Below normal engine temperature, Clogged primary fuel filter element, Clogged secondary fuel filter element, Water or dirt in the fuel system, Dirty or faulty injection nozzles, Air in fuel system, Improper type of fuel | Remove and check thermostat, Clean or replace filter element, Replace secondary filter element, Drain, flush, fill and bleed system, Have your dealer check injection nozzles, Inspect clamps and hoses on suction side of fuel pump for air leak, Consult fuel supplier and use proper type of fuel for operating condition |
| Lack of engine power | Engine overloaded, Intake air restriction, Clogged primary fuel filter element, Clogged secondary fuel filter element, Improper type of fuel | Reduce load, Service air cleaner, Clean or replace filter element, Replace filter element, Consult fuel supplier and use proper type of fuel for operating conditions |
| Engine overheats | See 'Engine Overheats' in next category | |
| Below normal engine temperature | Improper valve clearance | Reset valves. Best done by dealer |
| Dirty or faulty injection nozzles | Replace injectors. Best done by dealer | |
| Temperature gauge shows temperature above 205°F (97°C) | Shut off the engine immediately. Use the Trouble Shooting Guide on page 21 to isolate the cause of the overheat. | |
| Shutdown is activated and temperature gauge shows within normal range | Check the engine crankcase oil level. If low, fill with recommended lubricating oil and restart. Watch the oil pressure gauge carefully and shut off the engine if it does not show a normal reading (20-60 PSI) after a few seconds of operation. If the oil level is normal, DO NOT restart the engine. Call your dealer for assistance. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Loose or corroded connections, Sulfated or worn out batteries. See the table for the matching fixes.
Documented causes: Loose or corroded connections. See the table for the matching fixes.
Documented causes: Sulfated or worn out batteries, Loose or defective electrical system ground wire. See the table for the matching fixes.