Diagnostic Instructions

DTC Descriptor

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	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Variable Effort Steering Actuator Control Circuit 1	C0450 02	C0450 04	C0450 01	--
Variable Effort Steering Actuator Control Circuit 2	C0450 02	C0450 04	C0450 01	--

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

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 controller, the DTC will be set.

C0450 02

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

C0450 04

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

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

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

Reference Information

Schematic Reference

Power Steering Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Variable Effort Steering System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the M72 Variable Effort Steering Actuator.
2. Test for less than 5 Ω between the control circuit terminal A and ground.

⇒	If greater than the specified value, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the K43 Power Steering Control Module.

3. Ignition OFF, test for less than 5 Ω between the control circuit terminal B and ground.

⇒	If greater than the specified value, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the K43 Power Steering Control Module.

4. Connect a test lamp between control circuit terminal A and control circuit terminal B.
5. Ignition ON, verify the test lamp briefly illuminates for approximately 1 s, then turns OFF.

⇒	If the test lamp is always ON, test for a short to ground on either control circuit. If the circuits test normal, replace the K43 Power Steering Control Module.

6. If all circuits test normal, test or replace the M72 Variable Effort Steering Actuator.

Component Testing

Static Test

1. Ignition OFF, disconnect the harness connector at the M72 Variable Effort Steering Actuator.
2. Test for 1.6-3.1 Ω between control terminal A and control terminal B.

⇒	If not the specified range, replace the M72 Variable Effort Steering Actuator.

3. Test for infinite resistance between each terminal and the M72 Variable Effort Steering Actuator housing case.

⇒	If not the specified value, replace the M72 Variable Effort Steering Actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.