Cooling Fan Control Circuit
Cooling fan control circuit malfunction detected.
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What it means (plain English)
The cooling fan isn't receiving the right signals from the PCM to turn on or off, which means it might not cool the engine properly.
What the computer is actually seeing
The Powertrain Control Module (PCM) expects to see a certain voltage (usually around 5V) at the fan control circuit. If it sees very little or no voltage, it sets the P0690 code.
What a healthy reading looks like
Expected signal voltage on the control wire should be around 0-5V when the fan is off, and close to battery voltage (12V or more) when on.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the wiring and connections for any signs of damage or corrosion.
- 22. Measure voltage at the cooling fan control circuit connector; it should be around 5V with the ignition on, engine off. If not, go to step 3.
- 33. Test the cooling fan relay by swapping it with another relay of the same type that's known to work. If the fan operates, replace the relay. If not, go to step 4.
- 44. Measure resistance on the cooling fan motor itself; it should be close to manufacturer's specifications. If it's open or shorted, replace the motor.
- 55. If all else fails, consider checking PCM grounds and power supply, then diagnose the PCM itself if necessary.
Common causes
- Damaged wiring or connectors in the cooling fan control circuit
- Faulty cooling fan relay
- Failed PCM or incorrect programming
- Cooling fan motor failure
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be safe for a short drive, but overheating can occur, so keep an eye on the temperature gauge.
Will this code come back after clearing it?
If the underlying issue isn't fixed, the code is likely to return.
Why does this code often pair with P0480?
P0480 indicates a problem with the fan operation; both codes relate to fan circuit issues.
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