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. |
Circuit/System Description
The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control set/coast and resume/accelerate switch signal circuit in order to detect when the driver has requested to perform a cruise control function. The BCM detects a specific voltage signal on the cruise control set/coast and resume/accelerate switch signal circuit when a switch is applied.
Conditions for Enabling Cruise Control
| • | The vehicle speed is greater than 40 km/h (25 mph). |
| • | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear. |
| • | The system voltage is within 9-16 volts. |
| • | The park brake is not applied. |
| • | The brake pedal is not applied. |
| • | The scan tool Brake Pedal Position Sensor parameter indicates released. |
| • | The scan tool Brake Pressure Sensor Voltage parameter is within the correct range. |
Diagnostic Aids
Caution: Refer to SIR Caution in the Preface section.
Important: Repair any brake system related symptoms and DTCs before performing this diagnostic.
Disable the inflatable restraint steering wheel module when performing this diagnostic table. Refer to SIR Disabling and Enabling.
In order to avoid misdiagnosis, inspect for the following:
| • | Ensure that the following cruise control switches are not stuck in the engaged position: |
| - | On/Off switch |
| - | Set/Coast switch |
| - | Resume/Accel switch |
| - | Cancel switch |
| • | Inspect for proper operation of the stop lamps and the braking system. Refer to Exterior Lighting Systems Description and Operation. |
| • | For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Circuit/System Verification
Important: Repair any brake system related symptoms and DTCs before performing this diagnostic.
Rotate the steering wheel to both steering stops while activating each cruise control switch separately. With a scan tool, observe all cruise control switch parameters in the ECM. Ensure that each cruise control switch activated and that each displayed switch position parameters do not match or reads Error, as the steering wheel is turned.
| ⇒ | If the parameters match with each depressed switch accordingly, go to Diagnostic Aids. |
Circuit/System Testing
Caution: Refer to SIR Caution in the Preface section.
Disable the inflatable restraint steering wheel module when performing this diagnostic. Refer to SIR Disabling and Enabling.
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement.
- Disconnect the harness connector of the cruise control switch.
- Ignition ON, measure for 10 volts or greater at the steering wheel control supply voltage circuit.
- Ignition OFF, test for an open, for a high resistance, for a short to ground, or for a short to voltage in the cruise control switch signal circuit.
| ⇒ | If less than 10 volts, check for an open/high resistance or for a short to ground on the cruise control supply voltage circuit. |
| ⇒ | If the circuit tests normal, test the component. If the component tests normal, replace the BCM. |
Component Testing
Caution: Refer to SIR Caution in the Preface section.
Disable the inflatable restraint steering wheel module when performing this diagnostic. Refer to SIR Disabling and Enabling.
Important: The cruise control switch must be ON in order to properly measure the resistance of the - SET, the + RES, and the Cancel switches.
- With the ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement.
- With the ignition OFF, disconnect C277 at the inflatable restraint steering wheel module coil.
- Measure the resistance between terminals E and C at 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 on the schematic for the ON/OFF, - SET, the + RES, and the Cancel switches.
| ⇒ | If any of the resistance measurements for the OFF, ON, - SET, + RES, and Cancel switches are not within the listed resistance values, replace the cruise control switch assembly. |
Function Switch | Minimum Resistance Value | Maximum Resistance Value |
|---|---|---|
OFF | O.L. | O.L. |
ON | 6.4k Ohms | 7.2k Ohms |
- SET | 2.2k Ohms | 2.4k Ohms |
+ RES | 3.7k Ohms | 3.9k Ohms |
Cancel | 1.4k Ohms | 1.6k Ohms |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
