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 08: Cruise Control Function Request Circuit Signal Invalid

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Cruise Control Switch Supply Voltage | 1 | B3794 08 | 1 | B3794 08
Cruise Control Switch Signal | B3794 08 | B3794 08 | 1 | B3794 08
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 set/coast and resume/accelerate 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 set/coast and resume/accelerate 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 malfunction indicator lamp (MIL) will not illuminate.

• | 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.

• | 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.

• | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .

### Reference Information

#### Schematic Reference

Cruise Control Schematics

#### Connector End View Reference

• | Cruise Control Connector End Views

• | Data Communication Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

1. Ignition ON, observe the scan tool Cruise Control Switch parameter in the BCM while pressing the various cruise control switches. The reading should be Error.

⇒ | If the Cruise Control Switch parameter toggles between On, Off, Resume, and Set accordingly with the depressed switches, go to Testing for Intermittent Conditions and Poor Connections .

2. Go to Circuit/System Testing.

### Circuit/System Testing

Caution: Refer to SIR Caution in the Preface section.

Disable the inflatable restraint steering wheel module when performing this diagnostic. Refer to SIR Disabling and Enabling .

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 cruise control on/off switch.
3. Ignition ON, measure for 10 volts or greater at the cruise control supply voltage circuit.

⇒ | If less than the specified value, check for an open/high resistance or a short to ground on the cruise control supply voltage circuit.

4. Ignition OFF, connect the harness connector at the cruise control on/off switch. Disconnect the harness connector at the cruise control set/cruise, resume/accelerate switch.
5. Ignition ON, cruise on/off switch ON, measure for 10 volts or greater at the cruise control switch signal circuit.

⇒ | If less than the specified value, check for an open/high resistance or a short to ground on the cruise control switch signal circuit between the cruise on/off switch terminal 6 and the cruise control set/cruise, resume accelerate switch terminal 6 (UK3)/terminal 3 (non UK3). If the circuit tests normal, replace the cruise on/off switch assembly.

6. Ignition OFF, test for an open/high resistance, a short to ground, or a short to voltage in the cruise control switch signal circuit.
7. Test the component. If the circuits and the component tests are normal, replace the BCM.

### Component Testing

Caution: Refer to SIR Caution in the Preface section.

Disable the inflatable restraint steering wheel module when performing this diagnostic. Refer to SIR Disabling and Enabling .

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 cruise control set/coast, resume/accelerate switch assembly.
3. Measure the resistance between terminals 6 (UK3)/3 (non UK3) and 7 (UK3)/4 (non UK3) 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 for the - SET and the + RES switches.

⇒ | If any of the resistance measurements for the - SET, and the + RES switches are not within the listed resistance values, replace the cruise control set/coast, resume/accelerate switch assembly.

Function Switch | Minimum Resistance Value | Maximum Resistance Value
--- | --- | ---
- SET | 1.2k Ohms | 1.3k Ohms
+ RES | 2.7k Ohms | 3.0k 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