Input/Turbine Speed Sensor Circuit Malfunction

What it means

This sensor measures the speed of the transmission input shaft, which the transmission computer compares with output speed to control shifts and detect slipping. When its signal is lost, the transmission usually enters a backup mode with harsh shifts or a single gear.

Symptoms4

• Harsh or erratic shifting.
• Transmission stuck in one gear.
• Odd tachometer behavior on some cars.
• Check engine or transmission warning light on.

Possible causes5

• Failed input speed sensor.
• Damaged or fluid-contaminated connector or wiring.
• Metal debris stuck to the magnetic sensor tip.
• Low transmission fluid.
• Internal mechanical transmission fault (less common).

How to diagnose and fix5

1. Check transmission fluid level and condition.
2. Inspect the sensor connector and wiring.
3. Watch the sensor signal with a scan tool that reads the transmission computer.
4. Remove and clean debris from an external sensor, or replace it.
5. If there is a lot of metal debris, have the transmission inspected, since it indicates internal wear.

Repair cost

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

The sensor is usually low to moderate in cost, but on some cars it sits inside the transmission, which raises labor considerably.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.

Frequently asked questions