Cooling Fan Control Circuits

Category

Powertrain - Computer and Auxiliary Controls

Severity

Check Engine Light

Applies to

Silverado, Sierra, Tahoe, Corvette, Camaro

Related

No single generic twin. See OBD Codes List

Findings, check these first

• Faulty cooling fan control relay with welded or burned contacts
• Short to voltage or ground on the fan relay control circuit
• Corroded relay socket terminals in the underhood electrical center
• Failed PCM quad-driver output for the fan relay circuit

Standard procedure

1. Swap the cooling fan relay with a known-good identical relay and retest
2. Test the relay control circuit for shorts to voltage and ground
3. Inspect the underhood fuse block for green corrosion on the relay pins
4. Verify PCM quad-driver command with a Tech2 or GDS2 before condemning the module
5. Repair wiring first; replace the PCM only as a last resort

Look up another code

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Related Computer and Auxiliary Controls codes

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