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 Descriptor
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

* Ignition ON.
* Battery Voltage Must be Between 9 - 16 volts.



Conditions for Setting the DTC

* The BCM detects a short to ground or open on the BCM B+ circuit.
* The BCM detects a short to ground or short to voltage on the cruise control switch signal circuit.
* The BCM detects an invalid voltage signal on the cruise control switch signal circuit.



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 Views)
Description and Operation

Cruise Control Description and Operation (Description and Operation)
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, 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 X3 harness connector at the BCM.
2. Verify that a test lamp illuminates between the BCM F9 fuse B+ circuit terminal 3 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect the X3 harness connector at the BCM.
4. Disconnect the harness connector at the turn signal/multifunction switch.
5. Ignition ON, test for B+ between the B+ circuit terminal 6 and ground.

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

6. Ignition ON, test for B+ between the B+ circuit terminal 6 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.

7. Ignition ON, verify that a test lamp does not illuminate between B+ and the signal circuit terminal 5.

• If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit test normal, replace the BCM.

8. If all circuits test normal, test or replace the turn signal/multifunction switch.



Component Testing

1. Disconnect the harness connector at the turn signal/multifunction switch.
2. Cruise control switch ON, measure the resistance between terminal 5 and terminal 6 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.








Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) .

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