For 1990-2009 cars

### 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 Descriptor

DTC B3794: Cruise Control Function Request Circuit Signal Invalid

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Reference | 1 | B3794 | -- | --
Signal | 1 | B3794 | B3794 | --
1. Cruise Control Malfunction

### Circuit/System Description

The cruise control switch is an input to the instrument panel cluster (IPC). The IPC monitors the cruise control set/coast and resume/accelerate switch signal circuit in order to detect when the driver has requested to perform a cruise control function. The IPC detects a specific voltage signal on the cruise control switch signal circuit when a switch is applied. The IPC sends a serial data message to the engine control module (ECM), indicating the status of the cruise control switches.

### Conditions for Running the DTC

• | The ignition is ON.

• | The cruise switch is ON.

### Conditions for Setting the DTC

The IPC detects an invalid voltage signal on the cruise control switch signal circuit.

### Action Taken When the DTC Sets

The cruise control system is disabled.

### Conditions for Clearing the DTC

The current DTC clears when the fault is no longer present.

### 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

### Circuit/System Verification

Ignition ON, observe the scan tool Cruise Mode Signal parameter. The reading should be 0.0 V and change when the cruise control switch is turned ON, and while the resume and set switches are pressed.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the cruise control switch.
2. Ignition ON, test for 11-13 V between the ignition reference circuit terminal 4 and ground.

⇒ | If less than the specified range, test the ignition reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPC.

3. Verify the scan tool Cruise Mode Signal parameter is less than 1 V.

⇒ | If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the IPC.

4. Install a 3A fused jumper wire between the signal circuit terminal 1 and the ignition reference circuit terminal 4. Verify the scan tool Cruise Mode Signal parameter is greater than 11 V.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPC.

5. If all circuits test normal, test or replace the cruise control switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Cruise Control Switch Replacement

• | Control Module References for IPC replacement, programming, and setup.