Transmission

P0722 — Output Speed Sensor Circuit No Signal

Severity: medium Drive with care, to a shop

What P0722 means

The transmission control module (TCM) or engine computer is not seeing pulses from the output speed sensor, even though the vehicle should be moving. This signal is used to calculate vehicle speed and gear slip and to decide when to shift. Without it, the transmission usually goes into a fail-safe mode.

Symptoms

  • Transmission will not shift or stays in one gear
  • Speedometer dead or erratic
  • Transmission limp mode
  • Check Engine or transmission warning light on
  • Harsh or delayed shifts
  • Cruise control not working

Possible causes

  1. Failed output speed sensor
  2. Open or shorted wiring near the transmission
  3. Corroded or damaged sensor connector
  4. TCM not receiving vehicle speed (VSS) data
  5. Metal debris on the sensor or damaged tone ring
  6. Faulty TCM or PCM (rare)

How to diagnose

  1. Scan all codes and freeze frame data, and look for ABS or other speed sensor codes
  2. Compare scan tool vehicle speed with actual speed and ABS wheel speeds
  3. Inspect the sensor, connector and harness at the transmission for damage, fluid and corrosion
  4. Check transmission fluid level and condition, and inspect the sensor for metal debris
  5. Test sensor resistance, power and ground per the manufacturer's diagram
  6. Test wiring to the TCM for opens and shorts to ground
  7. Inspect the tone ring or reluctor
  8. If wiring and sensor are good, check the TCM and software updates

Common fixes

  • Replace the output speed sensor
  • Repair or replace the damaged wiring harness section
  • Clean or replace the connector and remove corrosion
  • Fix the source of missing speed data (ABS sensors, data bus)
  • Replace the tone ring or correct the source of debris
  • Replace or reprogram the TCM if confirmed faulty

Questions and answers

What does P0722 mean?

The control module is receiving no signal from the transmission output speed sensor. The cause is most often the sensor, its connector or the wiring.

Can I drive with P0722?

Only briefly and carefully, for example to a shop. The transmission may enter limp mode and not shift, and the speedometer may stop working.

Why is my speedometer dead with P0722?

Vehicle speed is often calculated from this sensor's signal. Without it, the instrument cluster and other modules get no speed data.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.