OBD-II code · Powertrain (generic)
P0502 Vehicle Speed Sensor A Circuit Low
The primary vehicle speed sensor (VSS A) reports a signal voltage below the plausible lower limit. With no usable speed signal the ECU loses cruise control, gear-shift logic and certain anti-stall functions.
Is it safe to drive with P0502?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- PossibleSensor internal short
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.4–1.4 h
- Emissions test
- Usually unaffected
- Parts involved
- Vehicle Speed Sensor A, Vss Wiring
Related codes
- P2160Vehicle Speed Sensor B Circuit Low
- P04FFCatalyst Heater Circuit Performance Bank 2
- P0500Vehicle Speed Sensor "A" Malfunction
- P0501Vehicle Speed Sensor "A" Range/Performance
- P0503Vehicle Speed Sensor A Circuit Intermittent Erratic or High
- P0504Brake Switch "A"/"B" Correlation
- P0505Idle Air Control System Malfunction
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.