P0720Output Shaft Speed Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The output shaft speed sensor (Hall or inductive) reports the speed of the transmission output; it gives the gear ratio together with input speed and on many vehicles also the road speed for speedometer and cruise control. P0720 is the general circuit code. Ford also uses it for 'no signal': while engine and turbine speed show the vehicle moving, the sensor reports under 100–200 rpm for 5–30 s; ZF's 6HP26 in Ford vehicles flags an open or short after 0.6 s. Subaru-based systems (Saab 9-2X) flag an impossible 255 km/h or 0 km/h while driving and light the MIL after two trips, substituting the other sensor. GM does not use P0720 but P0722. Speedometer and cruise control may fail, often with a vehicle speed code as well.
- What you may notice
- Speedometer drops out or jumps
- Warning lamp, limp mode or fixed gear
- Harsh shifts, cruise control not working
- Likely causes
- LikelySpeed sensor faulty (Hall IC or coil open or shorted)
- LikelyConnector or harness corroded, chafed or loose pins (with internal sensors also the pass-through connector)
- PossibleMetal debris on the sensor magnet or damaged reluctor wheel
- RareTransmission module or its sensor supply faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.