Caution: Refer to SIR Caution in the Preface section.
Disable the inflatable restraint steering wheel module when performing this diagnostic table. Refer to SIR Disabling and Enabling in SIR.
Circuit Description
The cruise control set/coast switch is an input to the throttle actuator control (TAC) module. The TAC module uses the cruise control set/coast switch signal circuit in order to detect when the driver has requested to set the vehicle speed or to decelerate the vehicle speed. The TAC module detects a voltage signal on the cruise control set/coast switch signal circuit when the switch is applied. The TAC module sends a serial data signal to the powertrain control module (PCM) via the universal asynchronous receiving/transmitting (UART) serial data circuit indicating the status of the set/coast switch.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The cruise control switch is ON. |
Conditions for Setting the DTC
The PCM receives a serial data signal from the TAC module indicating that the set/coast switch is ON for longer than 90 seconds.
Action Taken When the DTC Sets
| • | The PCM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
| • | The cruise control system is disabled. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL/DTC. |
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 PCM Cruise Control Data data list. This will help eliminate the possibility of a internally open or shorted inflatable restraint steering wheel module coil. |
| • | Ensure that the set/coast switch is not stuck or sticking in the engaged position. |
| • | For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference : Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views Powertrain Control Module Connector End Views in Engine Controls - 5.7L, or Engine Controls Connector End Views in Engine Controls - 5.7L | |||
1 | Did you perform the Cruise Control Diagnostic System Check? | Go to Step 2 | |
Does the Cruise Set/Coast Switch parameter display On? | Go to Step 3 | Go to Diagnostic Aids | |
3 |
Does the Cruise Set/Coast Switch parameter display On? | Go to Step 4 | Go to Step 5 |
4 | Test the cruise control set/coast switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
6 | Inspect for poor connections at the harness connector of the throttle actuator control (TAC) module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
7 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement in Engine Controls - 5.7L. Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the cruise control switch. Refer to Steering Wheel Control Switch Assembly Replacement in Steering Wheel and Column. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
