P0503 The computer is getting a vehicle speed signal that is erratic, drops out, or reads too high

Vehicle speed sensor intermittent / erratic / high input

P0503 in short

P0503 means the engine computer sees a vehicle speed signal that is intermittent, erratic or higher than expected. Damaged wiring or connectors and a failing speed sensor are the usual causes. Check for ABS or wheel speed codes first, since the signal can come from those sensors. Get it checked soon.

The computer reads vehicle speed from a speed sensor, and on many cars from the wheel speed sensors. If the signal jumps around, cuts out, or does not agree with wheel speed, it sets P0503.

TroubleCodes.net lists damaged, burnt or corroded wiring and connectors, a defective speed sensor, non-standard wheel and tire sizes, and damaged reluctor rings (often in the wheel bearing) as the usual causes. A failed computer is rare.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Damaged or corroded wiring or connector at the speed sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists wiring and connector damage first, and an intermittent signal fits a loose or rubbed wire.
    What would change this
    Rises if wiggling the harness changes the speed reading. Falls if the wiring and connector test clean.

  2. Failed vehicle speed sensor

    Common general cause
    Why it ranks here
    The sensor itself is listed as a common cause, and a worn sensor gives erratic readings.
    What would change this
    Rises if wiring is fine but the signal stays erratic. Falls if the signal is clean once the wiring is repaired.

  3. Damaged reluctor ring or non-standard wheel and tire size

    Possible — needs testing
    Why it ranks here
    Listed as a possible cause; it matters mainly where the speed comes from wheel sensors or the tires were changed.
    What would change this
    Rises after a wheel bearing, tire or wheel change. Falls if the car still has stock wheels and tires.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Record all stored codes and freeze-frame data. Look into any ABS or wheel speed sensor codes first.

    Low riskTool: OBD-II scan tool

    • IfABS or wheel speed codes are also stored

      It meansFix those first; the speed signal may come from them.

      Go to step 2

    • IfP0503 is the only code

      It meansCheck the sensor wiring.

      Go to step 2

  2. Look over the speed sensor wiring and connector for rubbing, burns and corrosion, especially where it touches the body.

    Low risk

  3. Have the sensor's reference voltage, ground, resistance and continuity checked against the maker's figures, and the sensor removed to check for metal debris.

    Best left to a shopTool: multimeter, service data

    Warning:Removing a speed sensor means working under a raised vehicle and may let transmission fluid out; use proper stands and catch the fluid.

Symptoms

  • Check engine light
  • Speedometer or odometer erratic or not working
  • Cruise control not working
  • Harsh, erratic or delayed automatic shifts Gets more serious: stop and have it checked.

How to fix

On your vehicle

Chevrolet

  • 2015 · Corvette

    Supported by vehicle data

    Chevrolet bulletin PI1439A covers a diagnostic tip for a check engine light where only P0503 is set with no other symptoms (also PI1439, dated 2015-03-13) on 2015 vehicles. Whether it is still current is not verified.

  • PI1439AStatus unverified

    Diagnostic tip for MIL on with only P0503 set

    2015corvette · issued · NHTSA 10113641

    Preliminary informational bulletin with a diagnostic tip for a customer concern of the check engine light on where the technician finds only P0503 set with no other symptoms, on the 2015 Corvette. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • PI1439Status unverified

    Diagnostic tip for MIL on with only P0503 set

    2015corvette · issued · NHTSA 10113749

    Earlier preliminary informational bulletin with the same diagnostic tip: check engine light on with only P0503 set and no other symptoms, on the 2015 Corvette. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Hyundai

  • 2000–2004 · Accent

    Supported by vehicle data

    Hyundai bulletin 0536003 covers P0130 and P0503 with a reverse-to-drive lurch while rolling backwards on automatic transaxle vehicles only on 2000-2004 vehicles. Whether it is still current is not verified.

  • 0536003Status unverified

    P0130 and P0503 with a reverse-to-drive lurch

    2000–2004accent · issued · NHTSA 10015328

    Covers P0130 (oxygen sensor) and P0503 (speed sensor malfunction), with a lurch from reverse to drive while rolling backwards on automatic transaxle vehicles only, on the 2000-2004 Accent. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ford

  • 2005 · F-250 Super Duty

    Supported by vehicle data

    Ford bulletin 051112 covers the ABS light on with possible codes C1175, C1236, P0500 and P0503 on 2005 vehicles. Whether it is still current is not verified.

  • 2005 · F-350 Super Duty

    Supported by vehicle data

    Ford bulletin 051112 covers the ABS light on with possible codes C1175, C1236, P0500 and P0503 on 2005 vehicles. Whether it is still current is not verified.

  • 051112Status unverified

    ABS light on with possible C1175, C1236, P0500 and P0503

    2005f-250-super-duty, f-350-super-duty, f-450-super-duty · issued · NHTSA 10016850

    Ford bulletin for the ABS light on with possible codes C1175, C1236, P0500 and P0503 on 2005 Super Duty trucks. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 0798Status unverified

    ABS light on with possible C1175, C1236, P0500 and P0503

    2005–2007f-250-super-duty, f-350-super-duty, f-450-super-duty · NHTSA 10021903

    Ford bulletin for the ABS light on with possible codes C1175, C1236, P0500 and P0503 on 2005-2007 Super Duty trucks. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Cadillac

  • 2003 · Deville

    Supported by vehicle data

    Cadillac bulletin 011403 covers P0503 with an intermittent vehicle speed sensor circuit, where customers may describe the speedometer going to zero, jerking, or cruise control that will not set or drops out (also 11272002, an automatic transmission P0503 bulletin) on 2003 vehicles. Whether it is still current is not verified.

  • 011403Status unverified

    P0503 vehicle speed sensor circuit intermittent

    2003deville · issued · NHTSA 10005101

    P0503 with an intermittent vehicle speed sensor circuit on 2003 DeVille and Seville. Customers may describe the speedometer intermittently going to zero, the vehicle jerking at times, being unable to set the cruise control, or cruise dropping out intermittently. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 11272002Status unverified

    Automatic transmission P0503 vehicle speed sensor circuit intermittent

    2003deville · issued · NHTSA 10008611

    Automatic transmission bulletin for P0503 with an intermittent vehicle speed sensor circuit on 2003 DeVille and Seville. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 2002 · MPV

    Supported by vehicle data

    Mazda bulletin 0102502 covers the malfunction indicator light on with P0340, P0503, P0443, P0660 or P1487 stored on 2002 vehicles. Whether it is still current is not verified.

  • 0102502Status unverified

    MIL on with P0340, P0503, P0443, P0660 or P1487 stored

    2002mpv · issued · NHTSA 10000387

    Mazda bulletin for the malfunction indicator light on with P0340, P0503, P0443, P0660 or P1487 stored on the 2002 MPV. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0500Vehicle speed sensor signal missing or not believable

    Shares causes Possible — needs testing

    P0500 is the general vehicle speed sensor malfunction code; P0503 is the intermittent/erratic/high version.

All Vehicle speed, idle control and engine electrical codes

Sources and review

  1. P0503 Vehicle Speed Sensor intermittent/erratic/high input — TroubleCodes.net
  2. On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles
  3. PI1439A: Diagnostic tip for MIL on with only P0503 set — Chevrolet
  4. PI1439: Diagnostic tip for MIL on with only P0503 set — Chevrolet
  5. 0536003: P0130 and P0503 with a reverse-to-drive lurch — Hyundai
  6. 051112: ABS light on with possible C1175, C1236, P0500 and P0503 — Ford
  7. 0798: ABS light on with possible C1175, C1236, P0500 and P0503 — Ford
  8. 011403: P0503 vehicle speed sensor circuit intermittent — Cadillac
  9. 11272002: Automatic transmission P0503 vehicle speed sensor circuit intermittent — Cadillac
  10. 0102502: MIL on with P0340, P0503, P0443, P0660 or P1487 stored — Mazda
Last reviewed
Written by
Saurabh K.
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