OBD Guide
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P0502

Vehicle Speed Sensor A Circuit Low

P0502 is an OBD-II diagnostic trouble code meaning: Vehicle Speed Sensor A Circuit Low. Common causes: damaged or broken speed sensor, signal wire shorted to ground. Estimated repair cost: $22–111.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$22–111 (est.)

Symptoms

  • Check Engine Light Is On
  • Speedometer does not work or shows zero speed
  • Incorrect automatic transmission operation (delayed shifts)
  • Disabling cruise control
  • Possible ABS error

Causes

  • Damaged or broken speed sensor
  • Signal wire shorted to ground
  • Destruction or damage to the toothed ring (tone ring)
  • Severe contamination of the sensor-toothed ring gap
  • Broken sensor cable screen
  • Malfunction of the ECU or ABS

How to Fix

  1. Read error codes with a scanner and check for ABS codes
  2. Visually inspect the speed sensor and gear ring
  3. Clean the sensor and tone ring area from dirt
  4. Check the signal wire for short to ground with a multimeter
  5. Check the sensor supply voltage (usually 5V or 12V depending on the type)
  6. Check the sensor signal shape while moving with an oscilloscope
  7. Replace the sensor or tone ring if it is faulty
  8. Reset the error and check the speedometer readings

Related codes

P0500P0501P0503C0035

Error P0502 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0502 code mean?

P0502 is an OBD-II diagnostic trouble code that indicates: Vehicle Speed Sensor A Circuit Low

What causes a P0502 error code?

The most common causes of P0502 include: Damaged or broken speed sensor; Signal wire shorted to ground; Destruction or damage to the toothed ring (tone ring); Severe contamination of the sensor-toothed ring gap.

How do I fix a P0502 diagnostic trouble code?

To fix P0502: Read error codes with a scanner and check for ABS codes. Visually inspect the speed sensor and gear ring. Clean the sensor and tone ring area from dirt. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0502?

Do not drive — repair immediately

How much does it cost to fix P0502?

The estimated repair cost for P0502 is $22–111. Actual cost depends on your vehicle, location, and labor rates.

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