P0528 Cooling Fan Speed Sensor Circuit No Signal

P0528 indicates no signal from the cooling fan speed sensor circuit. The fan may be commanded, but the controller does not see expected speed feedback.

Code details

Generic OBD-II · P0

System: Speed / Idle
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume the fan is not running just because speed feedback is missing; check actual fan operation and signal path.

Symptoms of P0528

Unstable, high, or low idle, or stalling.
Erratic speedometer, cruise-control, or shift behaviour.
Check-engine light with a hesitation or surge.

Common causes of P0528

A dirty throttle body, idle-control valve, or throttle-position sensor.
A failing vehicle-speed or wheel-speed sensor, or its wiring.
Vacuum leaks or a related sensor forcing the idle/speed strategy.

Useful checks before replacing parts

Check fan speed feedback while commanding the fan, fan module output, supply voltage, ground, connector condition, and freeze-frame temperature data.
Inspect open signal wiring, failed speed sensor output, damaged fan assembly, loose connectors, corroded terminals, and harness damage near the shroud.
Verify whether the fan physically runs and whether the missing signal is at the sensor, module, or controller input.

Related OBD-II codes

These nearby speed / idle entries can help compare wording and pin down the fault area.