Transmission Control Module (TCM)
P0571-BRAKE SWITCH 1 PERFORMANCE
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Transmission Control Module (TCM) monitors the brake switch 3 signal over the CAN Bus from the Totally Integrated Power Module (TIPM). If the Transmission is shifted into Drive position without confirming that the brake was depressed before the shift, a DTC will set.
- When Monitored:
After initial start and any time the shift lever is changed from park to drive.
System voltage between 9.0 and 16 volts.
No active CAN Bus DTCs present.
Vehicle speed is greater than 30 Km/h (18.5 mph) for at least 10 seconds.
- Set Condition:
The brake switch status does not change during a drive cycle with a vehicle speed greater than 30 Km/h (18.5 mph) for the period of 10 seconds.
It takes two consecutive problem identification trips to mature the fault. After two consecutive trips, the MIL is illuminated on the next key on cycle (start of a third trip).
Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.
1. CHECK IF THE DTC IS ACTIVE
1. With the scan tool, read Transmission DTCs.
Is the status Active or is the Starts Since Set counter 2 or less for this DTC?
Yes
- Go To 2
No
- Go To 6
2. CHECK FOR ENGINE BRAKE SWITCH DTCs
1. With the scan tool, check for engine brake switch DTCs.
2. With the scan tool, check if the brake switch changes when the brake pedal is pressed.
Are there any engine brake switch DTCs present or is the brake switch not registering any change on the scan tool?
Yes
- Testing and Inspection Perform the appropriate diagnostic procedure. If no DTCs are present and the brake switch does not seem to function, diagnose the brake switch as though a valid DTC is present.
- Perform the CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test.
No
- Go To 3
3. CHECK THE CENTER HIGH MOUNT STOP LAMP (CHMSL) OPERATION
1. While monitoring the CHMSL, depress the brake pedal.
Does the CHMSL illuminate?
Yes
- Go To 4
No
- Testing and Inspection Perform the appropriate diagnostic procedure.
4. CHECK THE TCM BRAKE SWITCH INPUT OPERATION
1. With the scan tool in TCM, depress the brake pedal and monitor the Brake Switch status.
Does the Brake Switch status change states when the brake pedal is depressed?
Yes
- Go To 6
No
- Go To 5
5. CHECK THE TIPM BRAKE SWITCH INPUT OPERATION
1. With the scan tool in TIPM, depress the brake pedal and monitor the Brake Switch status.
Does the Brake Switch status change states when the brake pedal is depressed?
Yes
- Using the schematics as a guide, check the Totally Integrated Power Module (TIPM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace and program the TIPM.
- Perform the CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test.
- If the DTC resets, Use the schematics as a guide and check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace and program the TCM.
- Perform the CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test.
No
- Check the (L53) Stop Lamp switch output circuit between the brake switch and the TIPM for an open or short to ground.
- Perform the CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test.
6. CHECK THE WIRING AND CONNECTORS
1. Test complete, the condition or conditions that originally set this DTC are not present at this time.
2. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
3. Wiggle the wires while checking for shorted and open circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test.
No
- Test Complete.