P0720

Output Shaft Speed Sensor Circuit

Transmission Generic OBD-II High

What it means

P0720 means the transmission's output shaft speed sensor circuit has a fault. This sensor measures how fast the output shaft turns, which the TCM uses for shift timing, torque-converter lockup, and often the speedometer. A bad signal causes harsh or erratic shifting, a wrong speedometer reading, or a protective limp mode. It points at the sensor or its wiring rather than at the engine's ability to start.

High

Can I keep driving? The transmission may shift harshly or drop into limp mode, and the speedometer can read wrong — driveable slowly, but get it fixed soon.

Real-world scan data

Seen in

457

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0720 scans

P0715in 14.2% of scans

P0723in 12.0% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on (sometimes a transmission warning light)
Harsh, erratic, or delayed shifting
Speedometer reading incorrectly or dropping out
Limp mode locking the transmission in one gear

Common causes

Most likely first

Faulty output shaft speed sensorLikely
Damaged wiring or a corroded connector at the sensorCommon
Debris on the sensor tip or a damaged reluctor/tone ringCommon
Low or degraded transmission fluid affecting the signal; less commonly a failed TCMLess often

How to diagnose & fix

Work through it in order

Scan and record freeze-frame data, and compare input vs. output speed readings to confirm the output sensor is at fault.
Inspect the sensor's connector and wiring for damage or corrosion; clean the sensor tip if accessible.
Check the transmission fluid level and condition.
Replace the output shaft speed sensor if its signal stays faulty with good wiring; consider the TCM only after the sensor and harness are ruled out.

FAQ

Quick answers

Is it safe to drive with P0720?+

Short, slow trips may be fine, but limp mode and harsh shifts can strain the transmission, and a wrong speedometer is a safety concern. Have it diagnosed soon.

Can I just clear P0720?+

It clears, but returns once the sensor signal faults again. Repair the sensor or wiring first.

Read & clear P0720 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX