Northern Lights M673 troubleshooting: 18 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Northern Lights M673 — full specs, parts & maintenance.
| Symptom | Cause | Remedy |
|---|---|---|
| Battery Will Not Charge | Loose or corroded connections, Sulfated or worn out batteries, Loose or defective alternator belt | Clean and tighten battery connections, Check specific gravity of each battery, Check electrolyte level of each battery, Adjust belt tension, Replace belt |
| Engine Hard to Start or Will Not Start | Loose or corroded connections, Sulfated or worn out batteries, Loose or defective alternator belt | Clean and tighten loose battery and harness plug connection, Check specific gravity of each battery, Check electrolyte level of each battery, Adjust belt tension, Replace belt |
| Starter Inoperative | Check DC circuit breaker, Loose or corroded connections | If the breaker is tripped, reset it, Clean and tighten loose battery and harness plug connection |
| Starter Cranks Slowly | Low battery output, Crankcase oil too heavy | Battery is too small, Battery cables are too small, Check specific gravity of each battery, Check electrolyte level of each battery, Fill with oil of appropriate viscosity, Clean and tighten all battery connections |
| Entire Electrical System Does Not Function | Check DC circuit breaker, Faulty connection, Sulfated or worn out batteries, Improper starting procedure | If breaker is tripped, reset it, Clean and tighten battery and harness plug connections, Check specific gravity and electrolyte level of each battery, See starting section of this manual, Take special note of Bypass Switch operation |
| No fuel | Check level of fuel in fuel tank | |
| 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, Overheated engine | 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, See “Engine Overheats” in next category |
| Lack of Engine Power | Intake air restriction, Clogged primary fuel filter element, Clogged secondary fuel filter element | Service air cleaner, Clean or replace filter element, Replace filter element |
| Engine Overheats | Improper valve clearance, Dirty or faulty injection nozzles, Air in fuel system, Improper type of fuel, Water or dirt in the fuel system, Clogged primary fuel filter element, Clogged secondary fuel filter element | Reset valves, Best done by dealer, Replace injectors, Best done by dealer, See your local dealer, Service air cleaner, Clean or replace filter element, Replace secondary filter element |
| High Fuel Consumption | Injection pump out of time | See your dealer |
| Low Oil Pressure | Low coolant level, Defective thermostat, Temperature gauge not working properly | Fill crankcase to proper level, Fill tank or radiator to proper level, Check thermostats, Check water temperature with thermometer and replace gauge if necessary |
| High Oil Consumption | Defective thermostat, Defective temperature gauge | Remove and check thermostat, Check water temperature with thermometer and replace gauge if necessary |
| Engine Emits Black or Gray Exhaust Smoke | Insufficient oil, Defective muffler (back pressure too high), Injection pump out of time, Improper fuel, Below normal engine temperature, Dirty or faulty injection nozzles | Call your dealer, Have dealer check back pressure, Call your dealer, Use correct fuel for temperature, Check water temperature to see if temperature gauge is working properly |
| Engine Knocks | Defective muffler (back pressure too high), Insufficient oil, Defective temperature gauge | Have dealer check back pressure, Call your dealer, Check water temperature with thermometer and replace gauge if necessary |
| Engine has shutdown | Check the temperature gauge. If above 205°F (96°C) for marine units or 230°F (110°C) for industrial units, shut off the engine immediately. Use the Trouble Shooting Guide on page 24 to isolate the cause of the overheat. | |
| Temperature gauge shows temperature within normal range but shutdown is activated | 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. | |
| Engine out of time | See your dealer | |
| Engine Temperature Below Normal | Thermostats not working properly | Check thermostats |
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, Loose or defective alternator belt. See the table for the matching fixes.
Documented causes: Loose or corroded connections, Sulfated or worn out batteries, Loose or defective alternator belt. See the table for the matching fixes.
Documented causes: Check DC circuit breaker, Loose or corroded connections. See the table for the matching fixes.