P0526
DTC P0526 (LGH)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0526
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Cooling Fan Speed Sensor Circuit
Diagnostic Fault Information
Circuit/System Description
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, and to reduce the cooling fan noise while maintaining powertrain cooling requirements. The ECM supplies a 5-volt reference and low reference circuit to the fan speed sensor in the cooling fan clutch. The speed sensor returns a signal pulse through the signal circuit in response to the reluctor track, which is also integral to the cooling fan clutch assembly.
Conditions for Running the DTC
* The engine is operating for greater than 10 S.
* The engine speed is greater than 550 RPM.
* The ECM commanded fan clutch solenoid duty cycle is greater than 45 percent.
* DTC P0526 runs continuously when the conditions above exist for greater than 30 S.
Conditions for Setting the DTC
* The ECM detects a loss of cooling fan speed signal for greater than 300 mS.
* The ECM detects that the cooling fan speed signal is greater or less than a predetermined threshold.
* DTC P0526 sets if either condition exists for greater than 3 S.
Action Taken When the DTC Sets
DTC P0526 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0526 is a Type B DTC.
Reference Information
Schematic Reference
Engine Cooling Schematics [1][2]Cooling System
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Cooling Fan Description and Operation (w/LGH) Cooling Fan
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. Verify DTC P06D2 is not set. If the DTC is set, refer to DTC P0641, P0651, P0697, P06A3, P06D2, or P06D6 P0641.
2. Engine operating, observe the scan tool Fan Speed parameter. The parameter should display a fan speed greater than 0 RPM.
3. Observe the DTC information with a scan tool. Verify DTC P0526 is not set.
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the fan clutch harness connector X142.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between low reference circuit terminal C and ground.
• If greater 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, test for 4.8-5.2 V between the 5 V reference circuit terminal E and ground.
• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Test for 4.8-5.2 V between the signal circuit terminal D and ground.
• If less than the specified range, test for a short to ground or an open/high resistance. If circuit/connections test normal, replace the ECM.
• If greater than specified range, test for a short to voltage. If circuit/connections test normal, replace the ECM.
• If the circuit/connections test normal, test the circuits of the fan clutch jumper harness for an open/shorted condition.
5. If all the circuit/connections test normal, test or replace the cooling fan clutch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Fan Clutch Replacement Service and Repair
* Control Module References Control Module References for ECM replacement, setup, and programming