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 on/off, set/coast, resume/accelerate and cancel 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, resume/accelerate and cancel 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 or brakes are not applied. |
Diagnostic Aids
Important: Repair any brake system related symptoms and DTCs before performing this diagnostic.
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 |
| • | With the Cruise On/Off Switch ON, rotate the steering wheel to both steering stops while activating each cruise control switch separately. With a scan tool, observe the Cruise Set/Coast Switch, the Cruise Resume/Accel Switch and the Cruise Cancel Switch parameters in the ECM and the Cruise Control Switch parameter in the BCM. Ensure that each cruise control switch activates and that each displayed switch position parameters match, as the steering wheel is turned. |
| • | Inspect for proper operation of the stop lamps and the braking system. Refer to Exterior Lighting Systems Description and Operation . |
| • | Electromagnetic interference (EMI) on the speed sensor signal circuit may cause erratic cruise control operation. |
Reference Information
Schematic Reference
Connector End View Reference
Cruise Control Connector End Views
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Important: The cruise on/off switch must be ON in order to view all of the cruise control parameters properly.
Ignition ON, observe the scan tool Cruise Control Switch parameter in the BCM while pressing the various cruise control switches. The reading should toggle between On, Off, Resume, Set and Cancel accordingly with the depressed switches.
Circuit/System Testing
Important: Repair any brake system related symptoms and DTCs before performing this diagnostic.
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
- Disconnect the harness connector of the steering wheel controls switch - left.
- Ignition ON, test for greater than 10 volts at the steering wheel control supply voltage circuit terminal 4 (Pontiac) or 1 (Chevrolet).
- Verify the scan tool Cruise Control Switch parameter is OFF.
- Ignition OFF, connect the harness connector at the steering wheel controls switch - left.
- Ignition ON, with the cruise control switch in the ON position, observe the scan tool Cruise Control Switch parameter. The parameter should display ON.
- Observe the scan tool Cruise Control Switch parameter while pressing the RES + portion of the cruise control switch. The parameter should display Resume.
- Observe the scan tool Cruise Control Switch parameter while pressing the SET - portion of the cruise control switch. The parameter should display Set.
- Observe the scan tool Cruise Control Switch parameter while pressing the Cancel portion of the cruise control switch. The parameter should display Cancel.
- If the circuits test normal, test or replace the ECM.
| ⇒ | If less than the specified value, test the supply voltage circuit for a short to ground or an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet) for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet) for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the steering wheel controls switch - left. |
| ⇒ | If not the specified value, test or replace the steering wheel controls switch - left. |
| ⇒ | If not the specified value, test or replace the steering wheel controls switch - left. |
| ⇒ | If not the specified value, test or replace the steering wheel controls switch - left. |
Component Testing
Steering Wheel Controls Switch - Left Test
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
- Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
- Measure the resistance between the supply voltage circuit terminal 4 (Pontiac) or 1 (Chevrolet) and the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet). Individually activate and hold each cruise control function switch and compare the resistance reading to the values for the On, Off, SET -, RES +, and Cancel switches.
| ⇒ | If any of the resistance measurements for the On, Off, SET -, RES + and Cancel switches are not within the listed resistance values, replace the steering wheel controls - left. |
Function Switch | Minimum Resistance Value | Maximum Resistance Value |
|---|---|---|
Off | O.L. | O.L. |
On | 6.5k Ohms | 7.1k 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 or ECM replacement, setup, and programming |
