GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptors

DTC B3794 08: Cruise Control Function Request Circuit Signal Invalid

DTC B3794 61: Cruise Control Function Request Circuit Actuator Stuck

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Steering Wheel Control Supply Voltage

1

B3794

1

B3794

Cruise Control Switch Signal

B3794

B3794

1

B3794

1. Cruise Control Inoperative/Malfunctioning

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.

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.

Diagnostic Aids

Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the Cruise Control Switch parameter in the BCM Cruise Control data list. This will help eliminate the possibility of a internally open or shorted inflatable restraint steering wheel module coil.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Cruise Control Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Ignition 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, Set, and Cancel as the applicable switch is pressed.

Circuit/System Testing

  1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  2. Disconnect the harness connector at the steering wheel controls switch-left.
  3. Ignition ON, test for greater than 10 volts at the supply voltage circuit terminal 4 (Pontiac) or 1 (Chevrolet).
  4. 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.
  5. Verify the scan tool Cruise Control Switch parameter is OFF.
  6. If not the specified value, test the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet) for a short to voltage. If the circuit tests normal, replace the BCM.
  7. Ignition OFF, connect the harness connector at the steering wheel controls switch - left.
  8. Ignition ON, with the cruise control switch in the ON position, observe the scan tool Cruise Control Switch parameter. The parameter should display ON.
  9. If not the specified value, test the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet) for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the steering wheel controls switch - left.
  10. Observe the scan tool Cruise Control Switch parameter while pressing the RES + portion of the cruise control switch. The parameter should display Resume.
  11. If not the specified value, test or replace the steering wheel controls switch - left.
  12. Observe the scan tool Cruise Control Switch parameter while pressing the SET - portion of the cruise control switch. The parameter should display Set.
  13. If not the specified value, test or replace the steering wheel controls switch - left.
  14. Observe the scan tool Cruise Control Switch parameter while pressing the Cancel portion of the cruise control switch. The parameter should display Cancel.
  15. If not the specified value, test or replace the steering wheel controls switch - left.
  16. If the circuits test normal, test or replace the BCM.

Component Testing

Steering Wheel Controls Switch - Left

  1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  2. Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
  3. Measure the resistance between the supply voltage circuit terminal 4 (Pontiac) or 1 (Chevrolet) and the signal circuit terminal 5 (Pontiac) or 3 (Chevrolet). Individually activate and hold each cruise control function switch and compare the resistance reading to the values for the On, Off, SET -, RES +, and Cancel switches.
  4. If any of the resistance measurements for the On, Off, SET -, RES + and Cancel switches are not within the listed resistance values, replace the steering wheel controls - left.

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Off

O.L.

O.L.

On

6.5k Ohms

7.1k Ohms

- SET

2.2k Ohms

2.4k Ohms

+ RES

3.7k Ohms

3.9k Ohms

Cancel

1.4k Ohms

1.6k Ohms

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Steering Wheel Control Switch Assembly Replacement
    •  Control Module References for BCM replacement, setup, and programming