Vehicle Speed Sensor A Circuit Low

What it means

The engine computer has detected that the vehicle speed sensor signal is too low or absent even though the vehicle is moving. This usually points to an electrical problem such as a short to ground, an open wire or a failed sensor.

Related codes: P0500P0501P0503P0720

Symptoms4

• Speedometer stays at zero while driving.
• Harsh shifts or the transmission stays in one gear.
• Cruise control stops working.
• Check engine light on.

Possible causes5

• Signal wire shorted to ground from chafing or damaged insulation.
• Open signal wire or sensor supply wire.
• Internal sensor failure.
• Corroded, loose or water-filled connector.
• Fault in the input circuit inside the computer (rare).

How to diagnose5

1. Watch vehicle speed on a scan tool while turning the wheels or driving slowly.
2. Unplug the connector and check the pins for corrosion or water.
3. Measure supply and ground voltage at the sensor connector if the sensor needs a supply, and compare with the manufacturer specification.
4. Check the signal wire for a short to ground or an open circuit back to the computer.
5. Test the sensor itself by comparing its resistance or output with the manufacturer specification.

How to fix5

1. Clean the connector and secure it properly.
2. Repair the shorted or broken wire and insulate it well.
3. Replace the vehicle speed sensor if it is proven faulty.
4. Test or replace the computer only after ruling out the sensor and wiring.
5. Clear the codes, then road test and confirm the speedometer works and the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a connector or wire repair, and higher when the sensor must be replaced, especially if it is hard to reach.

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