Northern Lights M668 troubleshooting: 11 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Northern Lights M668 — full specs, parts & maintenance.
| Symptom | Cause | Remedy |
|---|---|---|
| Battery will not charge | Loose or corroded connections: * Clean and tighten battery connections. Sulfated or worn out batteries: e Check specific gravity of each battery. ° Check electrolyte level of each battery. | Loose or corroded connections: * Clean and tighten battery connections. Sulfated or worn out batteries: e 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: ¢ Check specific gravity of each battery. Check electrolyte level of each battery. Defective electrical system ground wire: * Repair or replace. |
| Starter cranks slowly | Low battery output: Batteries too small. * Battery cables too smail. Check specific gravity of each battery. Check electrolyte level of each battery. Crankcase oil too heavy. Loose or corroded connections: ¢ Clean and tighten loose connections. | |
| Entire electrical system does not function | Check DC circuit breaker. Faulty connection: « Clean and tighten battery and harness plug connections. Sulfated or worm out batteries: * 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: e Check electrolyte level and specific gravity of battery. Excessive resistance in starting circuit: c Clean and tighten all connections on batteries. | |
| Engine runs irregularly or stalls frequently | Below normal engine temperature: e Remove and check thermostat. Clogged primary fuel filter element: c Clean or replace filter element. Clogged secondary fuel filter element: e Replace secondary filter element. Water or dirt in the fuel system. Dirty or faulty injection nozzles: c Have your dealer check injection nozzles. | |
| Lack of engine power | Engine overloaded: e Reduce load. Intake air restriction: * Service air cleaner. Clogged primary fuel filter element: c Clean or replace filter element. Clogged secondary fuel filter element: * Replace filter element. Improper type of fuel: c Consult fuel supplier and use proper type of fuel for operating conditions. | |
| Engine overheats | See “Engine Overheats” in next category. | |
| Improper valve clearance | See your local dealer. | |
| Dirty or faulty injection nozzles | See your local dealer. | |
| Injection pump out of time | See your local dealer. |
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: * Clean and tighten battery connections. Sulfated or worn out batteries: e Check specific gravity of each battery. ° Check electrolyte level of each battery.. See the table for the matching fixes.
Documented causes: Loose or corroded connections: * Clean and tighten loose battery and harness plug connection.. See the table for the matching fixes.
Documented causes: Low battery output: Batteries too small. * Battery cables too smail. Check specific gravity of each battery. Check electrolyte level of each battery. Crankcase oil too heavy. Loose or corroded connections: ¢ Clean and tighten loose connections.. See the table for the matching fixes.