GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra Denali 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC B3794

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

Cruise Control Switch Supply Voltage

1

B3794

1

B3794

Cruise Control Switch Signal

B3794

B3794

B0835

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 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 ignition is ON.
    • The cruise switch is ON.

Conditions for Setting the DTC
    • The BCM detects an invalid voltage signal on the cruise control + RES switch, - SET switch and the cancel signal circuit.
    • The above condition is present for 0.5 second.

Action Taken When the DTC Sets
    • The BCM stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The Cruise Control System is disabled.

Conditions for Clearing the DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction-free warm-up cycles.
    • The BCM receives a clear code command from the scan tool.

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
    •  Body Control System Schematics

Connector End View Reference

    •  Secondary/Configurable Control Connector End Views
    •  Data Communication 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
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, observe the scan tool Cruise Control Switch parameter in the BCM while pressing the various cruise control switches. The reading should match accordingly with each depressed switch.

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 of the steering wheel control switch assembly - left.
  3. Ignition ON, measure for 10 volts or greater between the 12-volt reference circuit terminal 1 and ground.
    4. ⇒If less than 10 volts, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, disconnect the harness connector X1 of the BCM.
  5. Ignition OFF, test for 1.0 ohm of resistance or less between the steering wheel control switch assembly - left terminal 3 and the BCM X1 terminal 3.
    6. ⇒If greater than the specified range, test the cruise control switch signal circuit for an open/high resistance.
  6. Ignition OFF, test for infinite resistance between the BCM X1 terminal 3 and ground.
    7. ⇒If less than the specified value, test the cruise control switch signal circuit for a short to ground.
  7. Test the component. If all circuits and the component tests are normal, 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, the + RES, and the Cancel switches.

  1. With the ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  2. With the ignition OFF, disconnect the harness connector at the steering wheel control switch assembly - left.
  3. Measure the resistance between terminals 1 and 3 at the cruise control switch side of the connector. Individually activate and hold each cruise control function switch and compare the resistance reading to the values on the schematic for the ON/OFF, - SET, the + RES, and the Cancel switches.
    4. ⇒If any of the resistance measurements for the OFF, ON, - SET, + RES, and Cancel switches are not within the listed resistance values, replace the cruise control switch assembly.

Function Switch

Minimum Resistance Value

Maximum Resistance Value

OFF

O.L.

O.L.

ON

6.5k ohms

7.0k ohms

- SET

2.2k ohms

2.4k ohms

+ RES

3.7k ohms

3.8k 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