C1525
DTC C1525
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC C1525 02
- Engine Running Signal (D+) Short to Ground
DTC C1525 08
- Engine Running Signal (D+) Signal Invalid
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
Circuit/System Description
A short to ground, poor resistance, or short to voltage on the generator turn ON signal or engine running signal circuit between the power steering control module and the underhood fuse block.
Conditions for Running the DTC
Engine running.
Conditions for Setting the DTC
Engine running signal detected low for 100 milliseconds.
Action Taken When the DTC Sets
* The steering boost is increased step-wise (intemittent condition).
* The steering boost is decreased step-wise (No signal condition).
Conditions for Clearing the DTC
The trouble code is deleted after the system was switched on 1 times and there was no fault recognised.
Diagnostic Aids
Confirm the vehicle is or is not equipped with a rear electrical center configuration. Verify scan tool is correctly identifying REC equipped status on the vehicle.
Reference Information
Schematic Reference
Power Steering Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Power Steering System Description and Operation (TRW) (Power Steering System Description and Operation (TRW))Power Steering System Description and Operation (ZF) (Power Steering System Description and Operation (ZF))
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Circuit/System Verification
Ignition ON, Engine Running, with a scan tool observe the Electronic Hydraulic Power Steering (EHPS) Engine Running Signal (D+) Inactive/Active scan tool data.
Circuit/System Testing
1. Ignition OFF, disconnect the underhood junction block connector X2, and the power steering control module connector X1.
2. Ignition ON, verify signal voltage between the power steering connector X12, terminal 5 (male side) and ground. The signal voltage should be less then 0.3 volts.
• If greater than the specified value, verify the vehicle does not carry a rear junction block. Test for a short to voltage on the engine running signal circuit, between power steering connector X12, terminal 5 (male side) and connector X2, terminal 26 (wiring harness side) of the underhood fuse block. Test for a short to voltage of underhood junction block connector (wiring harness side) terminal 5, underhood junction block (wiring harness side) terminal 40, underhood junction block connector (wiring harness side) terminal 8, and electro hydraulic power steering module (wiring harness side) terminal 5.
• If less than the specified value, verify the vehicle carries a rear junction block. Test the signal circuit for a short to ground or open/high resistance on the engine running signal circuit, between power steering connector X12, terminal 5 (male side) and connector X2 and terminal 26 (wiring harness side) of the underhood fuse block.
• If less than the specified value, verify the vehicle does not carry a rear junction block. Test the signal circuit connector X2, terminal 40 and ground of the underhood junction block for a short to voltage. If the circuit tests normal, test or replace the underhood junction block.
Component Testing
1. Ignition OFF, disconnect the powersteering harness connector X12, terminal 5 (male side) harness connector and the underhood fuse block.
2. Test for greater than 500 kOhm between the underhood junction block terminal 40 (wiring harness side) and ground.
• If less than the specified value, verify the vehicle does not carry a rear junction block. Test the signal circuit for a short to ground or an open/high resistance.
3. Test for greater than 500 kOhm between X12 inline connector terminal 5 (male side) and ground.
• If less than the specified value, test for a short to ground on the signal circuit. If the circuit tests normal, test or replace the power steering control module.
• If greater than the specified value, test for 0-5 Ohms between X12 inline connector terminal 5 (male side), and terminal 26 underhood junction block (wiring harness side), and terminal 8 (wiring harness side). If less than the specified range, test for a short to ground or an open/high resistance on the signal circuit. If the circuit tests normal, test or replace the power steering control module.
4. Test for 0-5 Ohms between the underhood junction block connector terminal 5 (wiring harness side) and the underhood junction block terminal 40 (wiring harness side).
• If less than the specified range, test or replace the power steering control module.
• If greater than the specified range, test the signal circuit for a short to ground or an open/high resistance. If all circuits test normal, test or replace the underhood junction block.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Important: For any module replacement a set procedure needs to be followed. A "Reset" needs to be performed from the PROGRAMMING menu of the current system with the Tech 2 BEFORE replacing the module.
* Power Steering Pump Replacement (TRW) (Service and Repair)Power Steering Pump Replacement (ZF) (Service and Repair)
* Power Steering Pump Wiring Harness Replacement (Service and Repair)
* Underhood Electrical Center or Junction Block Replacement (Underhood Electrical Center or Junction Block Replacement)