Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control on/off, set/coast, and resume/accelerate switch signal circuits in order to detect when a cruise control function switch has been activated. The BCM detects a predetermined voltage signal when a cruise control function switch is applied, with each switch having a different voltage value. The BCM sends a GMLAN serial data message to the engine control module (ECM) / powertrain control module (PCM) indicating the status of the cruise control switches.
• | 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. |
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 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 switch |
- | + RES switch |
• | Proper operation of the brake lamps--Refer to Exterior Lighting Systems Description and Operation . |
Electromagnetic interference (EMI) on the speed sensor signal circuit may cause erratic cruise control operation.
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
Cruise Control Connector End Views
⇒ | If the displayed switch positions in the Cruise Control Switch parameter match with each depressed switch accordingly, replace the ECM (non 2.0L) / PCM (2.0L). |
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 .
⇒ | If less than 10 volts, check for an open/high resistance or for a short to ground on the cruise control supply voltage circuit. |
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 .
⇒ | If the resistance does not show continuity when switched ON and open when switched OFF, replace the cruise control on/off switch assembly. |
⇒ | If any of the resistance measurements for the - SET and + RES are not within the listed resistance values, replace the cruise control set/cruise, resume/accelerate switch assembly. |
Function Switch | Minimum Resistance Value | Maximum Resistance Value |
---|---|---|
OFF | O.L. | O.L. |
ON | 0.0k Ohms | 0.5k Ohms |
- SET | 1.2k Ohms | 1.3k Ohms |
+ RES | 2.7k Ohms | 3.0k Ohms |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM, PCM (2.0L), or ECM (non 2.0L) replacement, setup, and programming |