P0568

DTC P0568

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 P0568
- Cruise Control Set Switch Circuit




Diagnostic Fault Information






Circuit/System Description

The cruise control switch is an input to the engine control module (ECM). The ECM monitors the cruise control switch signal circuit in order to detect when a cruise control function switch has been activated. The ECM detects a predetermined voltage signal when a cruise control function switch is applied, with each switch having a different voltage value.


Conditions for Running the DTC

* The ignition is ON.
* The cruise control switch is ON.



Conditions for Setting the DTC

The ECM detects that the Set/Coast switch is applied for longer than 90 seconds.


Actions Taken When the DTC Sets

* The malfunction indicator lamp (MIL) will not illuminate.
* The cruise control system is disabled.



Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear after 40 malfunction-free ignition cycles have occurred.



Reference Information
Schematic Reference

Cruise Control Schematics ([1][2]Cruise Control)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Cruise Control Description and Operation (Description and Operation)
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)

Scan Tool Reference

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


Circuit/System Verification

Engine ON, while rotating the steering wheel to both steering stops, observe the scan tool Cruise Control Switch parameter while pressing each of the cruise control switches. The parameter should toggle between ON, OFF, Resume, Set, and Cancel as the applicable switch is pressed.


Circuit/System Testing

1. Ignition OFF, disconnect the X201 harness connector at the turn signal/multifunction switch.
2. Ignition ON, test for B+ between the ignition voltage circuit terminal A8 and ground.

• If less than the specified value, test the ignition voltage circuit for a short to ground or an open/high resistance.

3. Verify the scan tool Cruise ON/OFF switch parameter displays OFF.

• If not the specified value, test the signal circuit terminal B8 for a short to voltage. If the circuit tests normal, replace the ECM.

4. Install a 3A fused jumper wire between the signal circuit terminal B8 and the B+ ignition voltage circuit terminal A8. Verify the scan tool Cruise ON/OFF Switch parameter displays ON.

• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the turn signal/multifunction switch.



Component Testing

Important: The cruise control switch must be ON in order to properly measure the resistance of the Set/Coast and Resume/Accel. switches.



1. Ignition OFF, disconnect the X201 steering column harness connector.
2. Cruise control switch ON, measure the resistance between terminals A8 and B8 on the cruise control switch side of the connector. Individually activate and hold each cruise control function switch and compare the resistance reading to the values in the table for the appropriate switch.

• If any resistance measurements for any of the switches are not within the listed resistance values, replace the turn signal/malfunction switch.








Repair Instructions

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

* Turn Signal Multifunction Switch Replacement (Turn Signal Multifunction Switch Replacement)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming