Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0568: Cruise Control Set Switch CircuitDiagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
B+ | 1 | P0564 | 1 | -- | P0564 |
Cruise Control ON/OFF Switch Signal | 1 | P0564 | 1 | P0567 P0568 | P0564 |
Cruise Control Resume/Accel. Switch Signal | 1 | 1 | 1 | P0567 | -- |
Cruise Control Set/Coast Switch Signal | 1 | 1 | 1 | P0568 | -- |
1. Cruise Control Malfunction | |||||
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
Connector End View Reference
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References 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
- Ignition OFF, disconnect the X204 harness connector at the turn signal/multifunction switch.
- Ignition ON, test for B+ between the B+ circuit terminal A8 and ground.
- Verify the scan tool Cruise ON/OFF switch parameter displays OFF.
- Install a 3A fused jumper wire between the signal circuit terminal B8 and the B+ circuit terminal A8. Verify the scan tool Cruise ON/OFF Switch parameter displays ON.
- If all circuits test normal, test or replace the turn signal/multifunction switch.
| ⇒ | If less than the specified value, test the circuit for a short to ground or an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal B8 for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the X204 steering column harness connector.
- 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. |
Function Switch | Minimum Resistance Value | Maximum Resistance Value |
|---|---|---|
OFF | O.L. | O.L. |
ON | 7.8k Ohms | 8.6k Ohms |
Set/Coast | 1.2k Ohms | 1.3k Ohms |
Resume/Accel. | 2.7k Ohms | 3.0k Ohms |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
