What does it mean?
Some vehicles are equipped with a sensor at the end of the cooling fan that detects movement during vehicle operation. The sensor is used to determine if the fan is operating on a vehicle equipped with a fan clutch or to verify that the fan speed commanded by the Powertrain Control Module (PCM) or Engine Control Module (ECM) matches the actual fan speed detected on an electric fan-equipped vehicle. The sensor used is a 3-wire Hall effect sensor that uses a 5-volt reference source from the PCM, a ground wire, and a signal wire to the PCM to determine the fan speed. In the case of DTC P0526, it means that the PCM/ECM has determined there is a fault with the sensor or the wiring.
Note: Be careful not to touch an electric fan, as it could turn on even when the vehicle is not running. This code is similar to P0527, P0528, and P0529.
Symptoms The symptoms of a DTC P0526 may include:
Illumination of the Malfunction Indicator Lamp (also known as Check Engine Light) The vehicle may overheat or run hotter than normal
Potential causes of a P0526 code include:
- Faulty fan clutch or electric fan
- Open circuit in the cooling fan sensor harness or loose connection Faulty PCM/ECM
- Faulty cooling fan speed sensor
- Broken accessory belt
Possible Solutions
Fan Clutch – Visually check that the fan is spinning while the engine is running. If the fan is not spinning, it could be due to a broken accessory belt or a faulty fan clutch. Replace the accessory belt, fan clutch, or cooling fan as necessary. Electric Fan Equipped – Visually check that the fan turns on and off when the PCM/ECM commands the fan to operate as the engine reaches certain temperatures. The fan may automatically activate when the air conditioning is turned on. If the fan does not operate, check the electrical harness connector, fuses, or relays that operate the electric fan. Some fans may be activated using an on/off relay or activated by Pulse Width Modulation (PWM) for variable speed fans. Repair the electric fan circuit, replace the electric fan, motor, or fan module as needed. Cooling Fan Sensor Harness – Check for loose connections and damaged wires that may have come into contact with the cooling fan. Disconnect the cooling fan sensor connector and the PCM connector and check the resistance using a Digital Volt-Ohm Meter (DVOM) with leads at each end of the power wire, signal wire, and ground wire (if connected to the PCM/ECM). Some vehicle manufacturers have issued a Technical Service Bulletin (TSB) for replacing the sensor cable harness. Replace or repair the harness. PCM/ECM – Disconnect the harness connector from the cooling fan sensor with the vehicle key in the on position/engine off. Check the 5-volt reference source from the PCM using a wiring diagram for reference, with the DVOM set to the volts scale, with the positive lead on the power wire and the negative lead to a known good ground. Check the ground using the DVOM positive lead connected to a good power source (positive battery terminal) and the negative lead on the harness ground wire. Replace the PCM/ECM if the reference voltage is not provided. Cooling Fan Speed Sensor – Disconnect the sensor harness connector and test for continuity using the DVOM set to the ohms scale between the power and ground wires; resistance should be present between the two wires. The signal wire can only be tested during actual fan operation by probing the harness connector with the DVOM set to the volts scale, or a graphing multimeter with the positive lead on the signal wire and the negative lead to a known good ground, as the Hall effect sensor used operates by creating a magnetic field that changes voltage while the fan is spinning. As the fan speed increases, the voltage should also increase. It may be necessary to monitor the fan speed using an advanced scan tool to verify that the actual fan speed matches the commanded fan speed. Replace the cooling fan speed sensor if a component failure is detected.