B3794

DTC B3794

Diagnostic Instructions

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

DTC Descriptors
DTC B3794 01
- Cruise Control Function Request Circuit Short To B+

DTC B3794 08
- Cruise Control Function Request Circuit Signal Invalid

DTC B3794 59
- Cruise Control Function Request Circuit/Component Protection Time Out

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 engine control module (ECM) receives the requested cruise control switch function from the BCM via a serial data message.

Conditions for Running the DTC

* The ignition is ON.
* The cruise switch 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.

Actions Taken When the DTC Sets

* The malfunction indicator lamp (MIL) will not illuminate.
* The cruise control system is disabled.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

Cruise Control Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

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

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

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. Ignition OFF, disconnect the harness connector at the K20 steering wheel control switch-left.
2. Ignition ON, test for B+ between the voltage reference circuit 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 and the signal circuit.

• 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 X3 harness connector at the K9 BCM.
5. Test for infinite resistance between the signal circuit terminal 9 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 K20 steering wheel control switch-left.

Repair Instructions

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

Control Module References (Programming and Relearning) for BCM replacement, setup, and programming