Cruise Control Malfunction Without K59

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 switches via the cruise control 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 switch signal circuit when a switch is applied. The BCM sends a serial data message to the ECM indicating the status of the cruise control switches.

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Engine ON, while rotating the steering wheel to both steering stops, observe the scan tool Cruise Control Switch and the Cruise Cancel Switch parameter while pressing each of the cruise control switches. The parameter should toggle between On, Off, Resume, Set and Cancel as the applicable switch is pressed.

1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
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 5.

⇒	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 61 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 turn signal/multifunction switch.

1. Disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Cruise control switch ON, measure the resistance between terminal 1 and terminal 5 while individually activating and holding each cruise control function switch and compare the resistance reading to the values in the table below.

⇒	If not within the specified resistance range, replace the turn signal/multifunction switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Cruise Control Malfunction With K59

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. The BCM sets DTC B3623 when it detects a stuck gap up/down switch.

The forward looking sensor (FLS) has the exclusive function of detecting, tracking and classifying targets within its specified field of view. The FLS has the ability to detect and react to objects of interest in its detection zone and is critical to the proper operation of the adaptive cruise control (ACC) system. When the distance sensing cruise control module (DSCC) detects that the FLS is out of alignment, DTC C1002 sets.

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Engine ON, while rotating the steering wheel to both steering stops, observe the scan tool Adaptive Cruise Control Switch and the Adaptive Cruise Cancel Switch parameter while pressing each of the cruise control switches. The parameter should toggle between On, Off, Resume, Set and Cancel as the applicable switch is pressed.

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

⇒	If less than the specified value, test the voltage reference 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 voltage reference 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.
7. Ignition OFF, disconnect the harness connector at the distance sensing cruise control module (DSCC).
8. Ignition OFF, test for less than 10 ohms between the ground circuit terminal 12 and ground.

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

9. Ignition ON, test for B+ between the voltage reference circuit terminal 15, and or the ignition voltage terminal 14 and ground.

⇒	If less than the specified value, test the voltage reference circuits for a short to ground or an open/high resistance. If the circuit tests normal, replace the distance sensing cruise control module.

10. Ignition OFF, disconnect the harness connector at the cruise control forward distance sensor.
11. Ignition OFF, test for less than 10 ohms between the ground circuit terminal 2 and ground.

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

12. Ignition ON, test for B+ between the voltage reference circuit terminal 5, and ground.

⇒	If less than the specified value, test the voltage reference circuits for a short to ground or an open/high resistance. If the circuit tests normal, replace the cruise control forward distance sensor module.

13. If all circuits test normal, test or replace the cruise control forward distance sensor module.

Important: The cruise control switch must be ON in order to properly measure the resistance of the Cancel, the Gap Up, and Gap Down, or Cancel switches.

1. Disconnect the harness connector at the steering wheel control switch-left.
2. Connect a DMM between terminals 1 and 2 of the steering wheel control switch-left.
3. Cruise control switch ON, measure the resistance while individually activating and hold each gap function switch and compare the resistance reading to the values for the Gap Up, Gap Down, Cancel or the neutral position.

⇒	If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the steering wheel control switch-left.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.