B3794

DTC B3794

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.



DTC Descriptors
DTC B3794 08
- Cruise Control Function Request Circuit Signal Invalid




Diagnostic Fault Information






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 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.


Conditions for Running the DTC

* The cruise switch is ON.
* The ignition is ON.



Conditions for Setting the DTC

* The BCM detects an invalid voltage signal on the cruise control switch signal circuit.
* The above condition is present for greater than 1 second.



Action Taken When the DTC Sets

* The BCM stores the DTC information into memory when the diagnostic runs and fails.
* The cruise control system is disabled.



Conditions for Clearing the DTC

* The DTC becomes history when the fault is no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.



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

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


Circuit/System Testing

1. Disconnect the harness connector X1 at the turn signal / multifunction switch.
2. Ignition ON, test for greater than 10 volts between the supply voltage circuit terminal 1 and ground.

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

3. Verify the scan tool Cruise Control Switch parameter is OFF.

• If not the specified value, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the BCM.

4. Ignition OFF, connect the harness connector at the turn signal / multifunction switch.
5. Ignition ON, with the cruise control switch in the ON position, observe the scan tool Cruise Control Switch parameter. The parameter should display ON.

• If not the specified value, test the signal circuit terminal 5 for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the turn signal / multifunction switch.

6. Observe the scan tool Cruise Control Switch parameter while pressing the RES + portion of the cruise control switch. The parameter should display Resume.

• If not the specified value, test or replace the turn signal / multifunction switch.

7. Observe the scan tool Cruise Control Switch parameter while pressing the SET - portion of the cruise control switch. The parameter should display Set.

• If not the specified value, test or replace the turn signal / multifunction switch.

8. If the circuits test normal, test or replace the BCM.



Component Testing

Important: The cruise control ON/OFF switch must be ON in order to properly measure the resistance of the - SET and the + RES switches.




Turn Signal/Multifunction Switch
1. Ignition OFF, disconnect the harness connector X1 at the turn signal / multifunction switch.
2. Measure the resistance between the supply voltage circuit terminal 1 and the signal circuit terminal 5. Individually activate and hold each cruise control function switch and compare the resistance reading to the values for the On, Off, SET - and RES + switches.

• If any of the resistance measurements for the On, Off, SET - and RES + switches are not within the listed resistance values, replace the turn signal / multifunction switch.








Repair Instructions

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

* Turn Signal Multifunction Switch Replacement (Turn Signal Multifunction Switch Replacement)
* Control Module References (Programming and Relearning)for BCM replacement, setup, and programming