Diagnostic Instructions
DTC Descriptor
DTC P0568 00 : Cruise Control Set Switch Circuit
Circuit/System Description
The cruise control resume/accel switch is an input to the engine control module (ECM) / powertrain control module. The ECM (5.3L) / PCM (3.8L) uses the cruise control resume/accel switch signal circuit in order to detect when the driver has requested to
accelerate the set vehicle speed or to resume the cruise control system. The ECM/PCM detects a voltage signal on the cruise control resume/accel switch signal circuit when the switch is applied.
Conditions for Running the DTC
• | The cruise control switch is ON. |
Conditions for Setting the DTC
The ECM detects that the set/coast switch is applied for longer than 60 seconds.
Action Taken When the DTC Sets
• | The ECM/PCM stores the DTC information into memory when the diagnostic runs and fails. |
• | The malfunction indicator lamp (MIL) will not illuminate. |
• | The ECM/PCM records the operating conditions at the time the diagnostic fails. The ECM/PCM stores this information in the Failure Records. |
• | The cruise control system is disabled. |
Conditions for Clearing the DTC
• | The DTC becomes history when the conditions for setting the DTC are no longer present. |
• | The history DTC clears after 40 malfunction-free warm-up cycles. |
Diagnostic Aids
Perform the following in order to avoid misdiagnosis:
• | Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the associated cruise control switch parameter in the ECM/PCM Cruise Control data list. This will help eliminate the possibility
of an internally open or shorted inflatable restraint steering wheel module coil. |
• | Ensure that the resume/accel switch is not stuck or sticking in the engaged position. |
Reference Information
Schematic Reference
Cruise Control Schematics
Connector End View Reference
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the cruise control switch.
- Ignition ON, cruise control switch ON, verify that the scan tool Cruise Set/Coast Switch parameter displays Off or Inactive.
⇒ | If the scan tool parameter reads On, Active or Invalid, test the cruise control switch signal circuit for a short to voltage. If the circuit tests normal, replace the ECM/PCM. |
- If all circuits test normal, replace the cruise control switch assembly.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.