For 1990-2009 cars only
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. |
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
Cruise Control Switch Signal | 1 | P0564 | 1 | P0567, P0568 | P0564 |
Cruise Control Switch Supply Voltage | 1 | P0564 | 1 | -- | P0564 |
1. Cruise Control Malfunction | |||||
Circuit/System Description
The cruise control switch is an input to the powertrain control module (PCM). The PCM monitors the cruise control on switch signal, the cruise control set/coast switch signal, and the cruise control resume/accel switch signal circuits in order to detect when a cruise control function has been requested. The throttle actuator control (TAC) module receives serial data messages from the PCM requesting cruise control functions.
Diagnostic Aids
Important: Repair any brake system related symptoms or DTCs before performing this diagnostic.
In order to avoid misdiagnosis, inspect for the following:
| • | Verify there are no DTCs set as current. If any DTCs are set as current, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostics/repairs before proceeding with symptom based diagnostics. |
| • | Inspect the cruise control switches for any sticking or binding conditions. |
| • | Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation . |
| • | Electromagnetic interference (EMI) on the speed sensor signal circuit may cause erratic cruise control operation. Verify that the vehicle speed readings on the scan tool in the PCM and TAC modules match the gage reading on the instrument panel cluster (IPC). |
Reference Information
Schematic Reference
Connector End View Reference
Powertrain Control Module Connector End Views
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
- Ignition ON, with a scan tool, observe all of the cruise control switch parameters in the PCM. Verify that the displayed switch position parameters match accordingly for each depressed switch.
- Road test the vehicle to verify that the speedometer matches the scan tool Vehicle Speed Sensor parameters in the PCM and the TAC modules.
| ⇒ | If the vehicle speed sensor parameters do not match closely, test the vehicle speed signal circuit for a short to voltage, short to ground or an open/high resistance. |
Circuit/System Testing
- Ignition OFF, disable the SIR system. Refer to SIR Disabling and Enabling.
- Disconnect the harness connector C4 at the turn signal / multifunction switch.
- Ignition ON, measure for 10 volts or greater at the supply voltage circuit terminal A.
- Ignition OFF, connect the harness connector C4 at the turn signal / multifuction switch.
- Ignition OFF, disconnect the harness connector C1 at the PCM.
- Ignition OFF, connect a test lamp between the cruise control on switch signal circuit terminal 11 and ground.
- Ignition ON, verify that the test lamp illuminates ON when the cruise switch is switched ON, and turns OFF when the cruise switch is switched OFF.
- Ignition OFF, connect a test lamp between the cruise control set/coast switch signal circuit terminal 39 and ground.
- Ignition ON, verify that the test lamp illuminates ON when the cruise set/coast is applied, and turns OFF when the cruise set/coast switch is unapplied.
- Ignition OFF, connect a test lamp between the cruise control resume/accel switch signal circuit terminal 25 and ground.
- Ignition ON, verify that the test lamp illuminates ON when the cruise resume/accel is applied, and turns OFF when the cruise resume/accel switch is unapplied.
- Ignition ON, verify that a test lamp illuminates between the TCC brake switch signal circuit terminal 46 and ground.
- If all circuits test normal, replace the PCM.
| ⇒ | If less than the specified value, test the supply voltage circuit for a short to ground or an open/high resistance. |
| ⇒ | If the test lamp is always ON, test the cruise control on switch signal circuit for a short to voltage. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the lest lamp is always OFF, test the cruise control on switch signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the test lamp is always ON, test the cruise control set/coast switch signal circuit for a short to voltage. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the lest lamp is always OFF, test the cruise control set/coast switch signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the test lamp is always ON, test the cruise control resume/accel switch signal circuit for a short to voltage. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the lest lamp is always OFF, test the cruise control resume/accel switch signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the turn signal / multifunction switch. |
| ⇒ | If the test lamp does not illuminate, test the TCC brake switch signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the stop lamp switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for PCM replacement, setup, and programming |
