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+ Voltage Reference | 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
Connector End View Reference
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
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
- Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
- Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground.
- Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminal 4.
- Ignition OFF, disconnect the X3 harness connector at the IPM.
- Test for infinite resistance between the signal circuit terminal 20 and ground.
- If all circuits test normal, test or replace the turn signal/multifunction switch.
| ⇒ | If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM. |
| ⇒ | 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. |
| ⇒ | If less than the specified value, test the signal circuit for a short to ground. |
Component Testing
Important: The cruise control switch must be ON in order to properly measure the resistance of the - SET, + RES, Cancel, Gap Up, Gap Down switches.
Turn Signal/Multifunction Switch
- Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
- Connect a DMM between terminals 1 and 4 of the turn signal/multifunction switch.
- Cruise control switch ON, measure the resistance while individually activation and holding each cruise control function switches and compare the resistance reading to the values in the table for the appropriate switch.
| ⇒ | If any of the resistance measurements for the individual switches are not within the specified resistance values, 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 |
Important: The cruise control switch must be ON in order to properly measure the resistance of the - SET, + RES, Cancel, Gap Up, Gap Down switches.
Steering Wheel Control Switch - Left
- Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
- Measure the resistance between the voltage reference 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.
| ⇒ | 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.
| • | Control Module References for IPM replacement, setup, and programming |
