The engine control module (ECM) uses the cooling fan speed signal in order to determine the actual fan speed in relation to the desired fan speed. The ECM uses the cooling fan speed signal in order to reduce the cooling fan noise and in order to maintain the powertrain cooling requirements. The ECM 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.

The engine is running at a minimum of 550 RPM.

DTC P0526 is a Type C DTC.

DTC P0526 is a Type C DTC.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Idle the engine.
2. Command the cooling fan clutch to 10 percent.
3. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
4. Command the cooling fan clutch to 80 percent.
5. Operate the engine at 2,000 RPM for 2 minutes. The difference between the Fan Speed and the Desired Fan Speed should remain less than 1,000 RPM throughout the speed transition.

1. Ignition OFF, disconnect the fan clutch at the shroud.
2. Measure between the low reference circuit terminal C and ground for less than 3 ohms.

⇒	If more than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, measure between the 5-volt reference circuit terminal E and the low reference circuit terminal E for 4.8-5.2 volts.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If more than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Install jumper wires in the 5-volt reference and low reference circuits between the harness and pigtail connectors at the shroud.

•	5-volt reference circuit terminal E

•	Low reference circuit terminal C

5. Measure DC voltage between the signal circuit terminal at the sensor pigtail connector and the 5-volt reference circuit jumper wire terminal.
6. Ignition ON, rotate the fan by hand. The voltage should toggle between approximately 5 volts and 0 volts.

⇒	If the voltage does not toggle correctly, test the three circuits in the pigtail harness for a short to ground, a short to voltage, or an open/high resistance. If the circuits test normal, replace the clutch.

7. Leave the jumpers from the previous step in place. Measure voltage between the signal circuit terminal D at the harness and pigtail connectors at the shroud.
8. Rotate the fan by hand. The voltage should toggle between approximately 5 volts and 0 volts.

⇒	If the voltage does not toggle correctly, test the signal circuit for a short to ground or a short to voltage. If the circuit tests normal, replace the ECM.

9. If all circuits and the speed sensor test normal, replace the ECM.

Relay Test

1. Connect the relay ground terminal to ground and the voltage supply terminal to appropriately fused power to energize the relay.
2. Test for less than 1 volt between the load voltage supply terminal and ground.
3. Connect the relay control circuit terminal to ground.
4. Test for B+ between the load voltage supply terminal and ground.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.