GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The cruise control multi function lever is wired directly to the PCM. The cruise on/off, set/coast and resume/accel signals are inputs to the fuel control portion of the PCM. These inputs allow the PCM to control and hold a requested speed. The cruise can be disengaged at anytime time by applying the brakes. This input is sent to the PCM by the cruise control brake switch.

Diagnostic Aids

If the cruise is inoperative, and no cruise control or brake switch DTC(s) are stored, check for the following conditions:

    • A malfunctioning cruise multi function switch/ wiring harness (opens or malfunctioning connections).
    • The clutch pedal switch is stuck in the open position.

Other conditions that will not allow the cruise control to engage that do not pertain to the cruise system.

    • The vehicle speed is below 25 MPH (if the cruise control is already set, the cruise will disengage at 20 MPH).
    • The vehicle is in 4 wheel drive low.
    • Any DTC that puts the vehicle in Back Up Fuel Mode (Back Up Fuel Mode affects the fuel control portion of the PCM). Refer to the appropriate DTC.
    •  More than one accelerator pedal position (APP) DTC is set.