B1397
DTC B1397 or B2815
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B1397
- Device Voltage Reference Output Circuit Low
DTC B2815
- Steering Wheel Controls Illegal Resistance Value
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies voltage to the audio steering wheel control switches and monitors the return signal. Each switch state is associated to a set resistance value and when pressed a specific voltage drop occurs across the resistor unique to the switch. The BCM identifies the switch selection and activates the feature.
Conditions for Running the DTC
* Battery voltage is between 9-16 volts
* The ignition is ON.
Conditions for Setting the DTC
B1397
The BCM senses a short to ground in the voltage circuit for more than 1 second.
B2815
The BCM senses a switch voltage that is higher than normal.
Action Taken When the DTC Sets
The BCM will ignore switch inputs.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction free ignition cycles have occurred.
Reference Information
Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics (Steering Wheel Secondary/Configurable Control Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Steering Wheel Controls Description and Operation (Steering Wheel Controls Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for Scan Tool Information
Circuit/System Verification
Ignition ON, observe the scan tool Steering Wheel Controls (SWC) Switch Voltage parameter. Pressing the switch should read voltage present, and drop to 0 volts when released.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
2. Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground.
• 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 BCM.
3. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminals listed below:
* Steering wheel control switch signal circuit terminal 5 - left switch.
* Steering wheel control switch signal circuit terminal 6 - right switch.
• If less than the specified value, test the signal circuits for a short to voltage or an open/high resistance. If the circuits test normal, replace the BCM.
4. Ignition OFF, disconnect the X1 harness connector at the BCM.
5. Test for infinite resistance between ground and the signal circuit terminals listed below:
* Steering wheel control switch signal circuit terminal 5 - left switch.
* Steering wheel control switch signal circuit terminal 6 - right switch.
• If less than the specified value, test the signal circuits for a short to ground.
6. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 1 at the left steering wheel control switch.
• If greater than the specified range, test the voltage reference circuit for a short to voltage
7. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 1 at the left steering wheel control switch.
• If not the specified value, test the voltage reference circuit for a short to ground.
8. Test for less than 1 ohm between the voltage reference circuit terminal 1 at the left steering wheel control switch and the voltage reference circuit terminal 2 at the right steering wheel control switch.
• If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
9. If all circuits test normal, test or replace the left or right steering wheel control switch.
Component Testing
1. Disconnect the harness connector at the right or left steering wheel control switch.
2. Connect a DMM between terminal 1 and terminal 5 (left switch) or terminal 6 (right switch) of either the left or right steering wheel control switches.
• If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the left or right steering wheel control switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Steering Wheel Control Switch Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming