B274A
DTC B274A
Diagnostic Instructions
* Perform the prior to Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle 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 B274A 03
- Sport Mode Switch Circuit Low Voltage
DTC B274A 07
- Sport Mode Switch Circuit High Voltage
DTC B274A 59
- Sport Mode Switch Circuit Protection Time-Out
Diagnostic Fault Information
Circuit/System Description
The Electronic Brake Control Module monitors the signal circuit from the Traction Control Switch, the SPORT (+) Mode Switch and the TOUR (-) Mode Switch. When the Traction Control Switch is pressed twice within five seconds the performance traction mode is available and entered into Performance Traction Control Mode 2-Dry. The SPORT (+) Mode Switch is used to select modes 2-5 and the TOUR (-) Mode Switch is used to deselect modes 5-1. Based on the driver selection and skill, one of the five track modes will integrate multiple calibrations in the powertrain and chassis electronics controlling the engine speed while modulating engine torque for maximum acceleration once the vehicle is moving.
The Electronic Brake Control Module then sends a serial data message to the Suspension Control Module to modify the shock damper rates which will change the ride and handling characteristics of the vehicle. The Electronic Brake Control Module then sends a serial data message to the Body Control Module which requests the Instrument Cluster via serial data to turn the Traction Control Off indicator and Stability Control Off indicator ON to notify the driver of the deactivation and the driver information center will display a message indicating the driver selected Performance Traction Control Mode.
Conditions for Running the DTC
* Ignition ON.
* The Electronic Brake Control Module is in normal operating mode.
Conditions for Setting the DTC
B274A 03
The Electronic Brake Control Module detects 1.34 V or less on the switch signal circuit.
B274A 07
The Electronic Brake Control Module detects 4.55 V or greater on the switch signal circuit.
B274A 59
If the switch signal is active for greater than 30 seconds, the switch will be considered stuck and the Electronic Brake Control Module will set this DTC.
Action Taken When the DTC Sets
* If entering the performance traction mode, the Electronic Brake Control Module will default to mode 2.
* If exiting the performance traction mode, the Electronic Brake Control Module will default to the last known state.
Conditions for Clearing the DTC
* A current DTC will clear on the next consecutive malfunction-free ignition cycle.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.
Reference Information
Schematic Reference
Electronic Suspension Control Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly - Primary
Description and Operation
* ABS Description and Operation (Without F55) ABS Description and Operation (Without F55)ABS Description and Operation (With F55) ABS Description and Operation (With F55)
* Electronic Suspension Control Description and Operation 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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Electronic Brake Control Module Sport Mode Switch parameter change states while switching between SPORT and TOUR modes.
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
3. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle system OFF, disconnect the harness connector at the S148E Multifunction Switch-Center Console. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the switch harness connector ground terminal 2 and ground.
• If 10 ohms or greater
1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Sport Mode Switch parameter is Malfunction.
• If not Malfunction
1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
2. Test for infinite resistance between the signal circuit terminal 8 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K17 Electronic Brake Control Module.
• If Malfunction
5. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module, ignition ON.
6. Test for less than 1 V between the signal circuit terminal 8 and ground.
• If 1 V or greater
• If less than 1 V
7. Test or replace the S148E Multifunction Switch-Center Console.
Component Testing
1. Ignition OFF, disconnect the harness connector at the S148E Multifunction Switch-Center Console.
2. Test for infinite resistance between the signal terminal 6 and the ground terminal 2 with the switch in the open position.
• If less than infinite resistance
Replace the S148E Multifunction Switch-Center Console.
• If infinite resistance
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Electronic Traction Control Switch Replacement Service and Repair
* Control Module References Control Module References for Electronic Brake Control Module replacement, programming and setup