1205
What This Code Means
External display board is not able to communicate with main board; Main board does not see communication from display board; Overcrank; Low to no fuel pressure while cranking; Overspeed (Over 72 Hz for three seconds); Throttle stuck open; Overspeed (Over 75 Hz for one second); Total loss of control; High temperature (Coolant temp greater than 246 ºF (119 ºC) for 1 second); Overcrank alarm; Overspeed (Over 72 Hz for three seconds with the throttle stuck open); Overspeed (Over 75 Hz for one second with the throttle stuck open, total loss of control); Low oil pressure while running; Controller Fault A; Overspeed (Instantaneous— Over 75 Hz for 1 second)
Possible Causes
- •Internal Harness Loop Broken (internal to the display board)
- •Internal harness connecting external display board to main board has become disconnected
- •Engine/Starter Problem
- •No Fuel Pressure
- •Stuck throttle
- •Air Flow Impeded / Flow Issue
- •Flow issue
- •Internal harness loop broken (external display board)
- •Low to no fuel pressure while cranking
- •Check the oil level
- •Air flow impeded
- •Internal Error
- •Broken stepper wire
Suggested Actions
- 1Fuel pressure has to be measured as low for at least 1200 ms before the overcrank alarm is set.
- 2Check the inlet/outlet for debris.
- 3Check coolant sensor circuit for proper operation.
- 4Check the inlet/outlet for debris
- 5Check coolant sensor circuit for proper operation
- 6Controller will reboot and transition to the same key state it was in before and resume operation.
- 7Because of the nature of cranking there is almost no insight into the cause of an overcrank alarm with the current sensors.
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Get a diagnosis walkthrough for 1205 on your specific Generac unit — cited to the OEM manual, not a forum guess.
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