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 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 instrument panel module (IPM). The IPM 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 IPM 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 IPM via a serial data message.


Conditions for Running the DTC

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



Conditions for Setting the DTC

* The IPM 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 IPM 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 (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cruise Control Description and Operation (Conventional Cruise Control) (Cruise Control Description and Operation (Conventional Cruise Control))Cruise Control Description and Operation (Adaptive Cruise Control) (Cruise Control Description and Operation (Adaptive Cruise Control))
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 parameter while pressing each of the cruise control switches. The Counts should match with the table below, as the applicable switch is pressed.






Circuit/System Testing

1. Disconnect the harness connector X2 at the 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. Ignition ON, test for 0.0 volts between the cruise control switch signal circuit and ground.

• If greater than the specified value, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the IPM.

4. Ignition OFF, connect the harness connector X2 at the multifunction switch.
5. Ignition ON, with the cruise control switch in the ON position, observe the scan tool Cruise 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 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 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 multifunction switch.

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



Component Testing


Multifunction Switch
1. Ignition OFF, disconnect the harness connector X2 at the 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 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 IPM replacement, setup, and programming