General Motors GM8.1L Engine

• The generator set runs but there is no electrical output
  Cause: Tripped circuit breaker
  Fix: Reset any tripped circuit breaker
• Engine fails to crank F1
  Cause: Fuse F1 in the engine harness blown
  Fix: Check Fuse F1 in the engine harness and replace if blown (15 amp)
• Engine cranks but fails to start
  Cause: Closed manual fuel valves
  Fix: Open all closed manual fuel valves
• High coolant temperature 123
  Fix: Check for low coolant level and add coolant and repair leaks as necessary; Remove obstructions to air flow; Open stuck air dampers; Service the engine cooling system
• WEAK BATTERY — Lamp: Warning 1442
  Cause: During cranking, the battery voltage is at or below the weak battery warning trip point for a time greater than or equal to the weak battery set time
  Fix: See code 441 for corrective action
• Under Frequency — Shtdn 1448
• TOO LONG IN IDLE — Lamp: Warning 2342
  Cause: Genset has been in Idle mode too long (10 minutes maximum)
• The generator set starts but shuts down
  Cause: Cause of the shutdown indicated by engine fault codes (Fault Code 115 low oil pressure, Fault Code 521 low coolant level, Fault Code 123 or 124 high coolant temperature)
  Fix: Press the engine fault code enable switch (Page 5-3) to determine the cause of the shutdown; If Fault Code 115 (low oil pressure), check for low oil and add oil as necessary; If Fault Code 521 (low coolant level), check for low coolant level and add coolant and repair leaks as necessary; If Fault Code 123 or 124 (high coolant temperature): check for low coolant level and add coolant and repair leaks as necessary, remove obstructions to air flow, open stuck air dampers, service the engine cooling system
• Speed/Hz Match — Shtdn 1469
• Speed Signal Lost — Shtdn 121
• Shutdown After BS — Shtdn 1123
• Short Circuit — Shtdn 1445
• S1 CB Not Open — Wrng 2397
• S1 CB Not Close — Wrng 2396
• Reverse Power — Shtdn 1459

Compiled from service & troubleshooting documentation across every generator set that uses the General Motors GM8.1L.

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.