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 InvalidDiagnostic 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
Connector End View Reference
Electrical Information Reference
| • | Circuit Testing |
| • | Wiring Repairs |
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 be Error.
- Go to Circuit/System Testing.
| ⇒ | 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 . |
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 .
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
- Disconnect the harness connector at the cruise control on/off switch.
- Ignition ON, measure for 10 volts or greater at the cruise control supply voltage circuit.
- 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.
- Ignition ON, cruise on/off switch ON, measure for 10 volts or greater at the cruise control switch signal circuit.
- Ignition OFF, test for an open/high resistance, a short to ground, or a short to voltage in the cruise control switch signal circuit.
- Test the component. If the circuits and the component tests are normal, replace the BCM.
| ⇒ | If less than the specified value, check for an open/high resistance or a short to ground on 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 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. |
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 .
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
- Ignition OFF, disconnect the harness connector at the cruise control set/coast, resume/accelerate switch assembly.
- 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.
| • | Control Module References for BCM replacement, setup, and programming |
