P0526

DTC P0526
Circuit Description
The powertrain control module (PCM) uses the cooling fan speed signal in order to determine the actual fan speed in relation to the desired fan speed. The PCM uses the cooling fan speed signal in order to reduce the cooling fan noise and in order to maintain the powertrain cooling requirements. The PCM supplies power and ground to the clutch hall effect sensor of the cooling fan clutch. The hall effect sensor returns a signal pulse through the speed signal circuit in response to the reluctor track, which is located inside the fan clutch. If during operation, the PCM detects a loss of the cooling fan speed signal, DTC P0526 will set.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0526 Cooling Fan Speed Sensor Circuit

Conditions for Running the DTC
^ The engine is running.
^ System voltage is greater than 8.5 volts.

Conditions for Setting the DTC
^ The PCM has detected a loss of cooling fan speed signal.
^ The above condition is present for at least 11 seconds.

Action Taken When the DTC Sets
^ The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store the condition as Freeze Frame/Failure Records data.
^ The PCM commands the cooling fan to 100 percent.

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the malfunction indicator lamp (MIL) after the third consecutive trip that the diagnostic test has run and passed.
^ Clear the DTC by using the Clear DTC Information function of the scan tool.

Diagnostic Aids
^ An inline connector could cause an intermittent DTC. Ensure to test for poor connections and pin retention at all inline connectors. Refer to system schematics for connectors and locations.
^ If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections.
^ Disconnect the harness connector of the cooling fan clutch from the shroud. Inspect the exposed wires between the harness connector and the tubing.
^ Inspect the cooling fan clutch harness in order to ensure that the clutch supply voltage circuit is not shorted to the following circuits:
^ The 5-volt reference circuit
^ The cooling fan speed signal circuit
^ The low reference circuit
^ DTC P0526 will set if the engine is started without the drive belt ON.

Test Description

Steps 1-9:

Steps 10-15:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests that the PCM receives a cooling fan speed signal through the cooling fan speed signal circuit. If answer to question is Yes, refer to all Diagnostic Aids.
3. This step tests for the proper operation of the cooling fan clutch hall effect sensor. The voltage should fluctuate between 0 - 5 volts. If the voltage stays at 0 volts, the signal circuit is shorted to ground.
4. This step tests for the proper operation of the 5-volt reference circuit and of the low reference circuit of the cooling fan clutch.