Fan Control Circuit
This code indicates an issue with the fan control circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine control module (ECM) is not receiving the correct signal from the fan control circuit, which can lead to overheating if the fan doesn't turn on when it should.
What the computer is actually seeing
The ECM expects to see a voltage signal in the range of 0.5V to 4.5V. If the voltage stays at 0V or exceeds 4.5V with the engine running, this code triggers.
What a healthy reading looks like
Signal voltage should be between 0.5V (fan off) and 4.5V (fan full 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.
- 1Check fan fuse and replace if blown. Decision: Fuse good? If yes, proceed to next step; if no, replace fuse and retest vehicle.
- 2Inspect the wiring and connectors for damage or corrosion. Decision: Wires and connectors good? If yes, proceed to next step; if no, repair or replace as needed and retest vehicle.
- 3Test the fan relay by applying 12V to the control terminal. The relay should click and the fan should operate. Decision: Relay works? If yes, proceed to next step; if no, replace relay and retest vehicle.
- 4Connect a scan tool and monitor the fan control signal while operating the engine. Decision: Signal voltage within expected range? If yes, ECM is likely fine; if no, replace ECM and retest vehicle.
Common causes
- Open or shorted wiring in the fan control circuit
- Failed fan relay
- Faulty fan motor
- Bad ECM
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Can I drive my vehicle with this code?
Yes, but if the fan is not working, the engine may overheat, especially in heavy traffic or high-temperature conditions.
Will this code come back after clearing it?
It may come back if the underlying issue isn't fixed; always address the root cause.
Why does this fan issue pair with overheating?
If the fan control circuit fails, the engine fan may not operate correctly to cool the engine, leading to overheating.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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