P0502 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Not safe to drive
P0502 on a BMW means the ECU is detecting a voltage on the vehicle speed sensor circuit that is lower than expected, typically because the signal wire is shorted to ground, the sensor has failed open, or the connector has lost contact. On vehicles that use the ABS wheel speed sensors as the primary speed input, P0502 usually accompanies an ABS wheel speed code.
- Severity
- Moderate · Electrical
- Typical repair cost, all makes
- €60-€650
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your BMW and Skanyx tells you what P0502 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 P0502 mean on a BMW?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P0502.
BMW 3 Series
2005-2024
On E90 and F30 3 Series, P0502 typically follows a complete ABS wheel speed sensor failure, often at the rear axle. Iron particles from the bearing collect on the sensor magnet and eventually short the signal to ground. Check the wheel bearing whenever you replace a rear sensor, because the debris that killed the old sensor comes from the bearing and will contaminate the new one.
What causes P0502 on a BMW?
Beyond the generic causes listed on the main P0502 page, these are the patterns noted for BMW models:
Rear ABS wheel speed sensor failure with short to ground
: BMW 3 Series
Iron debris from worn rear bearing contaminating the sensor
: BMW 3 Series
How to diagnose P0502 on a BMW with OBD2
- Read all stored codes. Companion ABS wheel speed codes (C-codes) usually point directly to the failed circuit
- Locate the suspect sensor and inspect the connector for water, corrosion, and damaged pins. Reseat the connector and clear the code to see if it returns
- With ignition off, measure resistance from the sensor signal pin to chassis ground. A near-zero reading confirms a short to ground in the wiring or the sensor
- Backprobe the sensor connector with the engine running and the wheels spinning. A Hall-effect sensor should switch between roughly 0 V and 5 V; a magnetic sensor should produce a small AC waveform that grows with speed
- If the wiring and sensor are healthy, inspect the reluctor ring for missing teeth, cracks, or a sheared press fit
How much does P0502 cost to fix on a BMW? (EUR)
Estimated repair costs for P0502 in EUR, compiled across makes. Expect BMW parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Repair sensor wiring or connector | €10–€40 | €50–€150 | €60–€190 | Moderate |
| Replace vehicle speed or ABS wheel speed sensor | €30–€120 | €40–€100 | €70–€220 | Moderate |
| Replace wheel bearing with integrated reluctor ring | €80–€250 | €150–€400 | €230–€650 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0502
These codes are often seen alongside P0502 or point to related issues, on any make:
Looking for the full P0502 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0502 guide