Circuit Description
Caution: Refer to SIR Caution in the Preface section.
Disable the inflatable restraint steering wheel module when performing this diagnostic table. Refer to SIR Disabling and Enabling .
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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3794 Cruise Control Function Request Circuit
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 set/coast and resume/accelerate 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 . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Master Electrical Component List | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Does the Cruise Control Switch parameter display Error? | -- | Go to Step 3 | Go to Step 4 | |
3 |
Does the Cruise Control Switch parameter display Error? | -- | Go to Step 9 | Go to Step 11 |
4 |
Does the Cruise Control Switch parameter display Error? | -- | Go to Step 7 | Go to Step 5 |
5 |
Does the Cruise Control Switch parameter display Error? | -- | Go to Step 7 | Go to Step 6 |
6 |
Does the Cruise Control Switch parameter display Error? | -- | Go to Step 7 | Go to Diagnostic Aids |
7 |
Important: The cruise control On/Off switch must be turned ON in order to correctly view the set/coast switch and the resume/accelerate switch resistance values with the DMM.
Do the cruise control function switch resistance values measure between the specified values? | Off = O.L. On = 7.8 K-8.6 K Resume = 2.7 K-3.0 K Set = 1.2 K-1.3 K | Go to Step 8 | Go to Step 11 |
8 | Test the ignition 1 voltage circuit for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 10 |
9 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 | Replace the cruise control switch. Refer to Steering Wheel Control Switch Assembly Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
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 on/off, 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 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 and - SET switch 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. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
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.
| ⇒ | If the Cruise Control Switch parameter toggles between On, Off, Resume and Set accordingly with the depressed switches, then 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 of the steering wheel controls switch - left.
- Ignition ON, test for 10 volts or greater at the steering wheel control supply voltage circuit terminal 4.
- 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 10 volts, check for an open/high resistance or for a short to ground on the steering wheel control supply voltage circuit. |
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 .
Important: The cruise control ON/OFF switch must be ON in order to properly measure the resistance of the - SET and the + RES switches.
- Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
- Ignition OFF, disconnect C277 at the inflatable restraint steering wheel module coil.
- Measure the resistance between terminals 4 and 5 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 and the + RES switches.
| ⇒ | If any of the resistance measurements for the OFF, ON, - SET and + RES switches are not within the listed resistance values, replace the steering wheel controls switch - left. |
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 |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
