Cruise Control Gap Up/Down Switch Malfunction

Cruise Control Gap Up/Down Switch Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) monitors the adaptive cruise control (ACC) gap adjustment switch signal circuit to determine the driver selected headway. The gap switch is a momentary contact switch that connects a series of resistors. Each switch state, inactive, up and down, corresponds to a specific resistance value. The BCM determines the switch selection by the voltage drop across the resistor.

Reference Information
Schematic Reference

Cruise Control Schematics (Conventional) (Cruise Control Schematics (Conventional))Cruise Control Schematics (Adaptive) (Cruise Control Schematics (Adaptive))
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cruise Control Description and Operation (Adaptive Cruise) (Cruise Control Description and Operation (Adaptive Cruise))Cruise Control Description and Operation (Conventional Cruise) (Cruise Control Description and Operation (Conventional Cruise))
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, verify that the ACC Gap Switch parameter toggles accordingly between Up, Down and Inactive as the appropriate gap switch is pressed.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
2. Ignition ON, test for B+ between the B+ circuit terminal 1 and ground.

• If less than the specified value, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

3. Test for B+ between the B+ circuit terminal 1 and the signal circuit terminal 2.

• If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Ignition OFF, disconnect the X2 harness connector at the BCM.
5. Test for infinite resistance between the signal circuit terminal 57 and ground.

• If less than the specified value, test the signal circuit for a short to ground.

6. If all circuits test normal, test or replace the steering wheel controls switch - left.

Component Testing

1. Disconnect the harness connector at the steering wheel controls switch - left.
2. Cruise control switch ON, measure the resistance between terminal 1 and terminal 2 while individually activating and holding each ACC gap function switch and compare the resistance reading to the values in the table below.

• If not within the specified resistance range, replace the steering wheel controls switch - left.





Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Steering Wheel Control Switch Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming