GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2009 🢒 STS 🢒 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 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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

1

B3794 08

B3794 59

B3794 08

Cruise Control Switch Signal

1

B3794 08

B3794 01

B3794 08

1. Cruise Control Malfunction

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 ignition is ON.
    • The cruise switch 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.

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

Connector End View Reference

Component 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

Control Module References 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 X2 harness connector at the turn signal/multifunction switch.
  2. Ignition ON, test for B+ between the B+ circuit terminal 1 and ground.
    3. ⇒If less than the specified value, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
  3. Test for B+ between the B+ circuit terminal 1 and the signal circuit terminal 4.
    4. ⇒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 IPM.
  4. Ignition OFF, disconnect the X3 harness connector at the IPM.
  5. Test for infinite resistance between the signal circuit terminal 20 and ground.
    6. ⇒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 turn signal/multifunction switch.

Component Testing

turn signal/multifunction switch

  1. Disconnect the X2 harness connector at the turn signal/multifunction switch.
  2. Cruise control switch ON, measure the resistance between terminal 1 and terminal 4 while individually activation and holding each cruise control function switch and compare the resistance reading to the values in the table below.
    3. ⇒If not within the specified resistance range, replace the turn signal/multifunction switch.

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Off

O.L.

O.L.

On

7.8k Ohms

8.6k Ohms

- SET

1.2k Ohms

1.3k Ohms

+ RES

2.7k Ohms

3.0k Ohms

Steering Wheel Control Switch - Left

  1. Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
  2. Measure the resistance between the B+ circuit terminal 1 and the signal circuit terminal 2. Individually activate and hold each gap function switch and compare the resistance reading to the values for the Gap Up, Gap Down, Cancel or the neutral position.
    3. ⇒If any of the resistance measurements for the Gap Up, Gap Down, Cancel or neutral position switches are not within the listed resistance values, replace the steering wheel controls - left.

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Neutral

O.L.

O.L.

Cancel

1.9k Ohms

2.1k Ohms

Gap Up

3.5k Ohms

3.7k Ohms

Gap Down

6.6k Ohms

6.8k Ohms

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turn Signal Multifunction Switch Replacement
    •  Control Module References for IPM replacement, setup, and programming