BMW DTC P0504 – Brake Switch ‘A’/’B’ Correlation
DTC P0504 meaning on BMW
The Diagnostic Trouble Code (DTC) P0504 for BMW indicates a correlation error between the brake switch ‘A’ and ‘B’. This means that the signals from both brake switches are not matching as expected by the vehicle’s control module.
BMW DTC P0504 symptoms
Symptoms of DTC P0504 on a BMW may include:
- Brake lights staying on constantly
- Cruise control not functioning properly
- Difficulty shifting out of park
BMW DTC P0504 causes
Common causes of DTC P0504 on a BMW include:
- Defective brake light switch
- Wiring or connection issues in the brake light circuit
- Faulty control module
BMW DTC P0504 seriousness
While DTC P0504 may not directly affect the drivability of the vehicle, it is important to address this issue promptly to ensure proper brake light operation and overall vehicle safety.
How to diagnose DTC P0504 on BMW
To diagnose DTC P0504 on a BMW, you can perform the following steps:
- Use a diagnostic scanner to retrieve the fault codes
- Inspect the brake light switch and its wiring for any visible damage
- Test the brake light switch for proper operation
- Check the brake light circuit for continuity
How to fix DTC P0504 on BMW
To fix DTC P0504 on a BMW, you can try the following solutions:
- Replace the faulty brake light switch
- Repair any damaged wiring or connections in the brake light circuit
- If necessary, replace the control module
How to erase DTC P0504 on BMW
To erase DTC P0504 on a BMW, you can clear the fault codes using a diagnostic scanner. After addressing the root cause of the issue and making the necessary repairs, you can reset the codes to see if the problem has been resolved.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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