P0504 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Not safe to drive
P0504 on a Volkswagen means the two internal circuits of the brake light switch do not agree. Modern brake switches send two signals to the ECU for safety: one that closes when the pedal is pressed and one that opens. If the ECU sees both circuits in the same state at the same time, it sets P0504. The fix is almost always a new brake switch, sometimes combined with a pedal position adjustment. VW, Audi, Skoda and SEAT apps often show this code as P050400; the last two digits are a failure-type byte.
- Severity
- Moderate · Electrical
- Typical repair cost, all makes
- €20-€150
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your Volkswagen and Skanyx tells you what P0504 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0504 mean on a Volkswagen?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the Volkswagen models that log P0504.
Volkswagen Golf
2003-2024
The brake light switch is the usual P0504 part on the Mk6 and Mk7 Golf, and it is a cheap one. Run the VIN through VW's own lookup before you buy, because anything still open on the car is done free at a dealer. Also check the pedal sensor alignment if the code appeared right after a clutch master cylinder job.
What causes P0504 on a Volkswagen?
Beyond the generic causes listed on the main P0504 page, these are the patterns noted for Volkswagen models:
Failed brake light switch on Mk6/Mk7
: Volkswagen Golf
Pedal sensor misalignment after clutch master cylinder replacement
: Volkswagen Golf
How to diagnose P0504 on a Volkswagen with OBD2
- Use a scan tool to view live brake switch data. Most ECUs show two signals (BLS and BTS or similar). Press the pedal and verify both change state cleanly together
- Inspect the pedal at rest. The switch plunger should be fully extended and resting against the pedal stop with no preload. A loose stop pad lets the pedal sit too low and pre-presses the switch
- Remove the connector and inspect for bent pins or corrosion. Reseat firmly and recheck
- If both signals stay correlated only when the connector is wiggled, repair the wiring. Otherwise, replace the brake switch as a unit
- Clear codes, perform any required relearn for cruise control, and confirm the brake lights work both at rest and when the pedal is pressed
How much does P0504 cost to fix on a Volkswagen? (EUR)
Estimated repair costs for P0504 in EUR, compiled across makes. Expect Volkswagen parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Adjust brake pedal position | €0–€0 | €20–€60 | €20–€60 | Easy |
| Replace brake light switch | €15–€40 | €20–€60 | €35–€100 | Easy |
| Repair brake switch wiring and connector | €5–€30 | €40–€120 | €45–€150 | Moderate |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0504
These codes are often seen alongside P0504 or point to related issues, on any make:
- P0571 · Volkswagen
- P0572
- P0573
- P0703
- U0140
Looking for the full P0504 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0504 guide