OBD-II trouble code
P0722: Output Speed Sensor Circuit No Signal
The transmission is getting no signal at all from the output speed sensor — the reading has gone to zero or flatlined while the car is clearly moving. It is the no-signal member of the output-speed codes: not a wrong value, but nothing. A dead or frozen speedometer and a drop into limp mode are signs to check. A broken circuit or a failed sensor can produce an absent signal. That is not a ranking of which one fails.
Quick facts
- System
- Powertrain
- Category
- Transmission / Speed Sensor
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $200 – $800 (external output speed sensor replacement)
- DIY difficulty
- Intermediate DIY
Browse every code in P0700–P0799, or start from the full code library.
What does P0722 mean?
P0722 sets when the PCM/TCM sees no output speed signal while other data — engine RPM, input speed, the fact that you're driving — says the output shaft must be turning. The output speed sensor reports how fast power is leaving the transmission toward the wheels, and the controller relies on it to calculate gear ratios, time shifts, and, where this vehicle uses that signal for them, the speedometer and the ABS or traction system. When that signal reads zero or is entirely absent, the TCM can't compute what gear it's in, so it may hold the single gear that transmission uses for failsafe. That gear is not always third. The service information names it. The point of failsafe is to keep the car movable while protecting the transmission. This is the 'no signal' end of the output-speed family, distinct from P0721 (signal present but implausible) and P0720 (general circuit malfunction).
A complete loss of signal is the absent-signal definition, not a claim about which part of the circuit has failed. The checks are a failed output speed sensor, an open or shorted wire, a disconnected or badly corroded connector, and a damaged reluctor/tone ring that the sensor can no longer read. A harness that has come loose or pins that have backed out are checks to make before replacing the sensor. Because the signal is fully gone rather than glitching, the fault is present while you test, so live data and a circuit test can show it. That is a description of the no-signal reading, not a comparison with P0718.
For the driver the signs to look for are a speedometer that reads zero or doesn't move, a drop into limp mode with a fixed gear and firm shifts, possible ABS/traction warning lights, and no torque-converter lockup. The car can still move, but keep the trip short, and shifting can be degraded. Confirm the signal is truly absent in live data, then test the sensor, its connector, and the wiring for an open circuit, and inspect the tone ring.
Common causes
- Failed output speed sensor producing no signal
- Open or shorted wiring in the sensor circuit
- Disconnected or badly corroded sensor connector
- Damaged reluctor / tone ring the sensor can no longer read
- Backed-out or broken connector pins
- Loss of sensor power or ground from a wiring fault
- Severe internal damage that has displaced the sensor or tone ring
Symptoms
- Check engine light with P0722 stored
- Speedometer reading zero or not moving while driving
- Immediate drop into limp / failsafe mode with a fixed gear
- Firm or harsh shifts and no torque-converter lockup
- ABS or traction-control warning lights on some vehicles
- Inability to calculate gear ratio, confusing shift behavior
Diagnostic steps
- 1.Confirm in live data that output speed truly reads zero while the vehicle is moving — this verifies a genuine no-signal condition. The speedometer can read zero and the transmission can be in limp mode, so you cannot judge your own speed: use a passenger to read the tool, or record the drive and review it parked.
- 2.Inspect the sensor connector for disconnection, corrosion, and backed-out pins before replacing the sensor.
- 3.Check the wiring for an open or short, and verify the sensor has proper power and ground where applicable.
- 4.Check the wire count before reaching for a resistance test. A two-wire magnetic (variable-reluctance) sensor is a coil, so an infinite or wildly out-of-spec reading condemns it. A three-wire Hall-effect or active sensor has no winding and will return a number that means nothing — on that type, confirm supply and ground at the connector and look for an output that changes as the shaft turns.
- 5.Inspect the reluctor / tone ring for damage that would leave the sensor with nothing to read.
- 6.Repair the open circuit or replace the sensor, then confirm output speed reads correctly and limp mode clears.
Repair cost
$200 – $800 (external output speed sensor replacement)
This pair is an external output speed sensor. When the sensor is the external case-mounted type RepairPal describes for a vehicle speed sensor — one or two fasteners — that estimator's average, updated 3 September 2026, is $395–$506, with examples from about $204 on a Civic to about $817 on an Altima. An internal sensor is not that job. RepairPal's transmission fluid change average, updated 3 September 2026, is $294–$356, with vehicle examples from about $162 to about $463. AutoZone's published band for a transmission rebuild is $1,800–$3,500, and for a full replacement $4,000–$8,000. Opening the transmission for a reluctor or for debris is not in this pair.
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Open the Repair Cost Estimator with transmission speed sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.