P2766
Input/Turbine Shaft Speed Sensor B Circuit Range/Performance
Transmission
Generic OBD-II
Medium
What it means
P2766 means the transmission control module sees an implausible or out-of-range signal from the "B" input/turbine shaft speed sensor, which measures how fast the transmission input is turning. Bad data leads to erratic or harsh shifting and possible limp mode. It's usually a sensor, tone-ring, or wiring fault, not an engine issue.
Medium
Can I keep driving? Drivable but may shift erratically or enter limp mode — the engine starts and runs fine; get it checked.
Common symptoms
What you'll notice
- Check-engine light on
- Erratic, harsh, or wrong-gear shifts
- Possible limp mode
- Speedometer or gear indicator issues
Common causes
Most likely first
- Faulty input/turbine shaft speed sensor BLikely
- Debris on the sensor tip or a damaged tone ringCommon
- Wiring or connector fault (intermittent or high resistance)Common
- Low or dirty transmission fluidLess often
- Faulty TCM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame and compare input/turbine, intermediate, and output speeds.
- Inspect the sensor and connector; check for debris on the tip.
- Check the wiring for opens, shorts, or high resistance.
- Verify transmission fluid level and condition.
- Replace the sensor if the signal is out of range; clear and road-test.
FAQ
Quick answers
Is it safe to drive with P2766?+
Usually yes, but the transmission relies on this speed signal to pick gears, so a fault can cause harsh or wrong-gear shifts and limp mode. The engine runs fine — get the sensor checked soon.
Can I just clear P2766?+
It returns once the transmission sees an implausible input-speed signal again. Repair the sensor, tone ring, or wiring to clear it for good.
Related codes
Often seen with P2766
Read & clear P2766 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX