Faulty input/turbine speed sensor 'B'; Damaged or corroded wiring or connector at the sensor; Open or short circuit in the sensor signal or ground circuit; Debris or metal particles on the sensor tip interfering with the signal; Internal transmission mechanical issue affecting sensor reading; Faulty transmission control module (less common)

DTC codes / P27xx · Transmission / P2766

P2766Input/Turbine Speed Sensor 'B' Circuit Range/Performance

Q: What does code P2766 mean?

Input/Turbine Speed Sensor 'B' Circuit Range/Performance. P2766 indicates that the transmission control module has detected an out-of-range or erratic signal from the input/turbine speed sensor 'B' circuit, which monitors the speed of the transmission input shaft. The computer compares this signal to other speed sensors and expected values, and when the signal falls outside the acceptable range or performance criteria, it sets this code.

P2766 indicates that the transmission control module has detected an out-of-range or erratic signal from the input/turbine speed sensor 'B' circuit, which monitors the speed of the transmission input shaft. The computer compares this signal to other speed sensors and expected values, and when the signal falls outside the acceptable range or performance criteria, it sets this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Illumination of the check engine light or transmission warning light
Harsh or delayed transmission shifts
Transmission may enter limp mode or fail to shift
Erratic speedometer operation (if the sensor shares data with the speedometer)
Poor fuel economy due to incorrect shift points
Often no symptoms besides the warning light

Common causes, most likely first

Faulty input/turbine speed sensor 'B'
Damaged or corroded wiring or connector at the sensor
Open or short circuit in the sensor signal or ground circuit
Debris or metal particles on the sensor tip interfering with the signal
Internal transmission mechanical issue affecting sensor reading
Faulty transmission control module (less common)

How to diagnose and fix it

Perform a visual inspection of the sensor and its wiring for damage or corrosion
Check the sensor resistance and compare to manufacturer specifications
Inspect the sensor tip for metallic debris and clean if necessary
Test the signal circuit for continuity and shorts to ground or power
Verify the sensor output with an oscilloscope or scan tool live data
Replace the sensor if faulty and clear the code
If the code persists, diagnose internal transmission components or the control module

Don't overlook the simple causes first

A common oversight is failing to check the sensor connector for loose pins or corrosion, which can mimic a failed sensor.
Metallic debris on the sensor tip from normal transmission wear can disrupt the magnetic pickup and set this code without any sensor failure.
This code can be set by a faulty ground connection shared with other sensors, so checking grounds is essential before replacing parts.
A slipping transmission or low fluid level can cause the input speed to deviate from expected values, triggering this code even when the sensor is good.
Some vehicles use the input speed sensor for cruise control or speedometer functions, so related symptoms may appear beyond transmission shifting.

Can I keep driving with P2766?

It is generally safe to drive with this code if the transmission shifts normally, but avoid heavy acceleration or towing until diagnosed. If the transmission enters limp mode or shifts harshly, seek professional diagnosis promptly to prevent further damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.