Vehicle Speed Sensor A Range/Performance
What it means
The engine computer receives a speed signal, but it does not match what it expects from engine speed, load and gear, or from other speed sources. This usually means the signal is weak or inaccurate rather than completely lost.
Symptoms4
- Inaccurate speedometer, or one that wavers at certain speeds.
- Erratic or mistimed transmission shifts.
- Cruise control stops working.
- Check engine light on.
Possible causes6
- Tire or wheel size changed from the factory specification.
- Metal debris on the sensor tip weakening the signal.
- Damaged or cracked tone ring or sensor drive gear.
- Weak speed sensor giving an intermittent signal.
- Electrical interference from wiring routed near high-voltage sources or with damaged insulation.
- Wrong tire size or gear ratio programming after a computer or transmission replacement.
How to diagnose5
- Confirm the tire size matches the size on the driver door label.
- Compare vehicle speed on a scan tool with wheel speeds and with real speed from a GPS.
- Check the sensor waveform on an oscilloscope for missing or weak pulses.
- Remove the sensor and inspect its tip and the tone ring teeth.
- Inspect the wiring for damaged insulation or routing near ignition wires.
How to fix5
- Return the tires to the factory size, or correct the tire size setting in the software.
- Clean the sensor tip and reinstall it.
- Repair the wiring or reroute it away from sources of interference.
- Replace the damaged sensor or tone ring.
- Clear the codes, then road test at different speeds and confirm the speedometer is accurate and the code does not return.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
The fix can cost almost nothing when tire size or a software setting is to blame, and rises when the sensor or tone ring must be replaced.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
I changed my tire size and the code appeared. Is that the cause?
Very likely. A different tire diameter changes the calculated speed so it no longer matches what the computer expects. Return to the original size, or correct the setting if the vehicle allows it.
How is it different from P0500?
P0500 points to a general fault or a missing signal, while P0501 means the signal is present but its value is implausible compared with other data.
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What was wrong? (optional)
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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