DTC C0450 - NV7

DTC C0450 — NV7

Diagnostic Instructions

DTC Descriptors

Diagnostic Fault Information

Circuit/System Description

The electronic brake control module (EBCM) controls the current through the variable effort steering actuator located on the steering gear. The current used to control the actuator is between 0-1 A. At low speeds and during car park manoeuvres the current is applied to the actuator causing the orifice to open increasing fluid flow and reducing the steering effort. At high speeds the orifice is commanded closed by reducing current through the actuator and restricting fluid flow increasing steering effort. The EBCM monitors and compares the commanded and feedback current parameters to detect malfunctions in the variable effort steering system.

Conditions for Running the DTC

Conditions for Setting the DTC

A malfunction, open/high resistance, an invalid signal or a high current is detected on the high control or low control circuit.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

The vehicle may need to be driven to view full 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

Note:  It is recommended that Component Testing is performed before Circuit/System Testing when diagnosing the actuator because the module will default and does not supply voltage to the sensor when the DTC is set.

1. Ignition OFF, disconnect the harness connector at the M72 Variable Power Steering Solenoid Valve.
2. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.

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

⇒	If the test lamp is always ON, test the control circuit terminal B for a short to ground. If the circuit tests normal, replace the K17 Electronic Brake Control Module.

⇒	If the test lamp is always OFF, test the control circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K17 Electronic Brake Control Module.

5. If all circuits test normal, test or replace the M72 Variable Power Steering Solenoid Valve.

Component Testing

Static Test

1. Ignition OFF, disconnect the harness connector at the M72 Variable Power Steering Solenoid Valve.
2. Test for 2.5-10 Ω between the control terminals A and B.

⇒	If not within 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 after completing the diagnostic procedure.