Technical Description of OBD-II Trouble Code
Range/Performance Issue with Fan Speed Sensor Circuit
This powertrain code (DTC) is a generic OBD-II code that applies to all vehicle makes and models (1996-newer). However, the specific repair steps may vary depending on the model.
What does this mean?
Some vehicles have a sensor at the end of the cooling fan that detects movement during vehicle operation. This sensor is used to determine if the fan is running on a vehicle with a fan clutch, or to verify the fan speed commanded by the Powertrain Control Module (PCM) or Engine Control Module (ECM) matches the actual fan speed detected on a vehicle with an electric fan.
The sensor used is a 3-wire, hall effect sensor that receives a 5-volt reference source from the PCM, a ground wire, and a signal wire to the PCM to determine fan speed. A P0527 code is triggered when the PCM/ECM determines that the actual fan speed does not match the desired or commanded speed.
Note: Be cautious when touching an electric fan as it may turn on even when the vehicle is not operating. This code is similar to P0526, P0528, and P0529.
Symptoms
Symptoms of a P0527 DTC may include:
Causes
Possible causes of a P0527 code include:
Possible Solutions
If the vehicle is equipped with a fan clutch, visually verify that the fan is spinning while the engine is operating. If the fan is spinning very slowly during a cold start, replace the fan clutch assembly. It may be necessary to use an advanced scan tool to see the actual fan speed in relation to the desired fan speed.
If the vehicle is equipped with an electric fan, visually verify that the fan is turning on and off when the PCM/ECM commands the fan to operate at certain temperatures. The fan may also be automatically turned on when the air conditioner is activated. Some fans may be turned on using an on/off relay or activated by Pulse Width Modulation (PWM) with variable speed fans.
It may be necessary to use an advanced scan tool to see the actual fan speed in relation to the commanded fan speed. If the fan speed is lower than the specified range, replace the electrical fan assembly or fan motor.
