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C0450




DTC C0450

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 Descriptors
DTC C0450 01
- Steering Assist Control Actuator Circuit Short to Battery

DTC C0450 02
- Steering Assist Control Actuator Circuit Short to Ground

DTC C0450 04
- Steering Assist Control Actuator Circuit Open

Diagnostic Fault Information





Circuit/System Description

The actuator is a variable electromagnetic actuator, which consists of one multiple-pole ring-style permanent magnet, with a pole piece, and an electromagnetic coil assembly. By commanding currents between -3 to +3 A through the coils the steering effort will be adapted accordingly.

Conditions for Running the DTC

* System voltage between 9-16 V
* Engine running

Conditions for Setting the DTC

The variable effort steering detects a short to battery, short to ground or an open circuit in the actuator circuits.

C0450 01

If the coil feedback voltage is measured greater than 8 V during the initialization of the module, the DTC will be set.

C0450 02

If the coil feedback voltage is measured less than 3.4 V during the initialization of the module, the DTC will be set.

C0450 04

If the coil current is measured to be less/greater than 1.0 A from the commanded current, the DTC will be set.

Action Taken When the DTC Sets

* DTC C0450 is stored in memory.
* The fault lamp illuminates or the driver information center displays the service power steering message.
* The variable effort steering module goes in to shutdown mode.

Conditions for Clearing the DTC

* The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.
* The variable effort steering automatically clears the history DTC when a current DTC is not detected in 40 consecutive communication wake-up enable cycles.

Diagnostic Aids

The vehicle may need to be driven to view full variable power steering solenoid valve commanded and actuator feedback data parameters.

Reference Information
Schematic Reference

Power Steering Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Variable Effort Steering System Description and Operation (Variable Effort Steering System Description and Operation)
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)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

Note: It is recommended that Component Testing is performed before Circuit/System Testing when diagnosing the variable power steering solenoid valve.

1. Ignition OFF, disconnect the harness connector at the M72 Variable Power Steering Solenoid Valve.
2. Ignition ON, test for less than 0.3 V between the control terminals listed below and ground.

* M72 Variable Power Steering Solenoid Valve, terminal A
* M72 Variable Power Steering Solenoid Valve, terminal B

• If greater than the specified value, test the control circuits for a short to voltage. If the circuits test normal, replace the K43 Power Steering Control Module.

3. Ignition OFF, disconnect the negative terminal of the C1 Battery.
4. Test for infinite resistance between the control circuit terminals listed below and B+.

* M72 Variable Power Steering Solenoid Valve, terminal A
* M72 Variable Power Steering Solenoid Valve, terminal B

• If not within the specified range, test the control circuit for a short to ground. If the circuits test normal, replace the K43 Power Steering Control Module.

5. Disconnect the harness connector at the K43 Power Steering Control Module. Test for less than 5 ohm between the control circuit terminals listed below:

* M72 Variable Power Steering Solenoid Valve, terminal A and K43 Power Steering Control Module, terminal 2
* M72 Variable Power Steering Solenoid Valve, terminal B and K43 Power Steering Control Module, terminal 3

• If greater than the specified value, test the control circuit for an open/high resistance.

6. If all circuits test normal, test or replace the M72 Variable Power Steering Solenoid Valve.
7. Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC C0450 does not set.

• If the DTC sets, replace the K43 Power Steering Control Module.

Component Testing

Static Test
1. Ignition OFF, disconnect the harness connector at the M72 Variable Power Steering Solenoid Valve.
2. Test for 1.6-3.1 ohm between control terminal A and control terminal B.

• If not the specified range, replace the M72 Variable Power Steering Solenoid Valve.

3. Test for infinite resistance between each terminal and the M72 Variable Power Steering Solenoid Valve housing case.

• If not the specified value, replace the M72 Variable Power Steering Solenoid Valve.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Steering Gear Replacement (Steering Gear)
* Steering Power Variable Control Module Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for power steering control module replacement, setup and programming

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