P0722
Output Shaft Speed Sensor Circuit No Signal.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 22
- FaultThe specific fault in that area
What it means
P0722 is the generic code for no signal from the output shaft speed sensor circuit. The transmission control unit expects a pulse signal from the output shaft speed sensor whenever the car is moving, and it saw none while other inputs, such as engine speed, load or road speed from other sources, suggested the output shaft should be turning. The sensor may be called a vehicle speed sensor on some models, and the exact location and design depend on the transmission.
Symptoms
- Speedometer not working or reading erratically
- Gearbox stuck in one gear (limp mode) or harsh, flared or delayed shifts
- Gearbox warning light or malfunction indicator lamp on
- Torque converter lock-up not engaging, with higher revs on a steady cruise
- Cruise control not working
- Poor fuel economy
Possible causes
- Faulty output shaft speed sensorlikely
- Damaged, chafed or broken wiring, or a short or open circuit in the sensor harnesslikely
- Corroded, loose or contaminated connector at the sensor or gearboxlikely
- Metal debris or contamination on the sensor tip, or a sensor that is loose or incorrectly seatedpossible
- Damaged or missing reluctor ring or tone wheel on the output shaftpossible
- Low or contaminated transmission fluid affecting the sensor or the gearboxpossible
- Faulty transmission control unit or its internal circuitrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting road speed, gear and engine speed when the code set, and check for other speed sensor or ABS wheel speed codes.
- Check the transmission fluid level and condition if a dipstick or check procedure is provided, as the method depends on the model.
- Visually inspect the sensor harness and connector for chafing, heat damage, fluid ingress, corrosion and bent or pushed-back pins.
- With a scan tool, watch the output shaft speed and road speed live data on a test drive and compare them with each other and with the input speed.
- Remove the sensor and inspect it for metal debris, damage and a correct seal or O-ring, then check the reluctor ring if it is accessible.
- Test the sensor supply, earth and signal circuits and the sensor resistance or output against the manufacturer's specification for that gearbox.
- Wiggle test the harness with the engine running or the wheels raised safely to look for intermittent signal loss.
- If the sensor and wiring are proven good, check the transmission control unit power, earth and for any applicable software update before suspecting the unit.
How to fix
- Replace the output shaft speed sensor with a correct part and fit a new seal or O-ring where one is used.
- Repair or replace damaged wiring and renew faulty connector terminals or the connector.
- Clean debris from the sensor and mounting area, and secure the sensor to the correct torque.
- Repair or replace a damaged reluctor ring or output shaft component, which may need gearbox removal depending on the model.
- Correct the fluid level or change contaminated fluid using the correct specification for the gearbox.
- Repair or replace the transmission control unit, or update its software where the manufacturer lists an update for this fault.
Can I keep driving?
The car can usually be driven carefully for a short time, but it may be in limp mode with poor shifting and no speedometer. Get it fixed soon, as driving on with erratic shifting can cause extra gearbox wear and reduces safety.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.