P0527 moderate

Cooling Fan Speed Sensor Circuit Range/Performance

The P0527 code means the vehicle's onboard diagnostic system has detected: Cooling Fan Speed Sensor Circuit Range/Performance. This is a moderate severity code.

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Keep driving?: Short distances only
DIY difficulty: moderate
Estimated cost: $100 - $500 (parts and labor)

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Common Symptoms

Check Engine Light on
Cooling fan speed feedback incorrect
Fan running at unexpected speed
Temperature control issues

Probable Causes (Ranked by Likelihood)

Cooling fan speed sensor reading outside expected range Very High
Fan motor speed deviating from commanded speed High
Intermittent fan speed sensor signal Moderate
Fan blade damage causing speed variation Low

Step-by-Step Diagnostic Procedure

Compare commanded fan speed to actual fan speed sensor reading with a scan tool
Inspect fan blades for damage or debris that could cause speed variation
Check fan speed sensor signal with an oscilloscope for clean, consistent pulses
Verify fan motor operation by commanding different speeds and monitoring response time

Frequently Asked Questions

What does range/performance mean for P0527?

Range/performance means the fan speed sensor is sending a signal but the reported speed does not match what the ECM commanded. The fan may be running too fast or too slow compared to the target speed.

Can a damaged fan blade cause P0527?

Yes. A cracked, broken, or debris-laden fan blade can cause the fan to spin at an incorrect speed or create vibration that affects the speed sensor reading, triggering P0527.

Is P0527 related to the AC system?

Yes. The cooling fan also serves the AC condenser. If fan speed control is unreliable, AC performance may suffer, especially during idle or low-speed driving when the condenser relies entirely on the electric fan for cooling.