5-7
UnclassifiedCooling
What This Code Means
Elevated level of CO in the area; Engine Head Temperature Sensor (EHT) issues; Incorrect resistance reading from EHT sensor; Crank Position Sensor (CKP) issues; Incorrect cranking voltage or frequency from CKP sensor; Incorrect resistance reading from CKP sensor
Possible Causes
- •The generator is producing carbon monoxide.
- •Faulty EHT sensor
- •Harness integrity issue between EHT sensor and ECM
- •Faulty CKP sensor
- •Harness continuity issue between CKP sensor and ECM
- •Continuity to ground on CKP sensor conductors
Suggested Actions
- 1The module is functioning properly and is protecting the operators.
- 2Test EHT sensor for resistance. If outside acceptable parameters, replace the EHT sensor.
- 3Disconnect EHT sensor from harness.
- 4Test Wire 820G to ground for 0 ohms or very low ohms.
- 5Test Wire 714 for voltage to ground (ECM must be active). Should be 4.5–5.0 VDC.
- 6If ground is not measured or 4.5 VDC is not measured, test harness for continuity of these circuits to the ECM.
- 7Use wiring diagram for point-to-point resistance readings.
- 8If CKP does not read correct output or resistance, replace the CKP sensor.
- 9Test CKP sensor for resistance.
- 10Test CKP sensor for cranking voltage and cranking frequency (Hz) by back probing Wires 79A (+ Hz signal) and 79B (- Hz signal).
- 11If CKP reads correct output or resistance, perform a point to point resistance check on the harness.
- 12Verify no continuity to ground on either conductor.
- 13Replace harness as needed.
ASK RUDY ABOUT THIS FAULT
Get a diagnosis walkthrough for 5-7 on your specific Generac unit — cited to the OEM manual, not a forum guess.
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