P2765

Code

Generic P — Powertrain

Input/Turbine Shaft Speed Sensor B Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 15 EN: 41 RU: 23

AI status

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Page language: EN

Causes

Open or short in the sensor signal wiring (to ground or battery)
Corroded, loose or damaged sensor connector
Failed input/turbine speed sensor (Bank B / Sensor B)
Damaged or missing reluctor/reluctor ring teeth at the turbine shaft
Metal debris or contamination affecting sensor reading
Faulty transmission control module (TCM/ECM) or poor module ground/power

Symptoms

Check Engine / Transmission warning lamp illuminated
Harsh, delayed, or erratic shifting; transmission may go into limp/safe mode
Torque converter lockup issues (surging, slipping or no lockup)
Incorrect or no vehicle speed/sensor-related indications displayed
Possible drivability complaints at certain speeds or load conditions
Intermittent operation that may change with engine/transmission temperature

What to check

Read freeze frame and live PIDs for Input/Turbine Shaft Speed (Sensor B) and related sensors
Confirm code is current and note when it sets (conditions, speed, temperature)
Visually inspect sensor connector and harness for damage, corrosion, or oil/metal contamination
Wiggle harness and connector while monitoring live data to reveal intermittent faults
Backprobe signal, ground and reference power at the sensor connector with key ON and engine running
Measure sensor resistance (if specified) and compare to manufacturer spec; check for open/short

Signal parameters

Sensor types: variable reluctance (magnetic pickup) or Hall-effect (digital) depending on vehicle
VR sensor: AC waveform whose frequency increases with shaft speed; amplitude typically rises with RPM
Hall sensor: square wave (0–5 V) where frequency correlates with shaft speed; 0 V to ~5 V swing
Expected behavior: clean periodic waveform with frequency proportional to turbine/input shaft speed; no signal or steady DC indicates a fault
Common faults visible on scope: no signal, flat line, constant DC, missing pulses, excessive noise, or amplitude collapse

Diagnostic algorithm

Verify code and record freeze-frame / live data. Note vehicle speed, engine RPM and when code sets.
Visually inspect sensor and wiring at the transmission bellhousing for damage, fluid intrusion, or debris.
Disconnect connector and inspect terminals for corrosion, bent pins, or contamination. Clean or repair as required.
With connector disconnected, measure sensor resistance (if specified by manufacturer). Replace sensor if open or out of spec.
Backprobe signal wire: with engine cranking and running, check for expected waveform using a scope. If no scope, check for AC voltage (VR) or pulsed DC (Hall) with multimeter while spinning the shaft.
Check for short to battery or ground between signal and supply/ground wires. Repair any shorted wiring.
Perform continuity/resistance check between sensor connector and TCM input pin to rule out wiring opens.
Wiggle test the harness while monitoring live sensor PID to find intermittent faults caused by movement.
Inspect reluctor ring/teeth and bellhousing for metal debris or damaged teeth that can cause false/no pulses. Repair or replace damaged components.
If wiring and sensor check good but signal at the TCM pin is missing or abnormal, verify TCM power/ground and consider module fault; consult OEM procedures before replacing TCM.
After repairs, clear the code and perform a road test to verify the repair and ensure the code does not return.

Likely causes

Sensor wiring chafed or pinched near bellhousing
Connector terminals corroded or pushed out
Sensor failed from heat, contamination or impact
Reluctor ring damaged by debris or broken teeth
Short to battery or ground in the harness
Poor TCM ground or internal TCM input circuit failure

Fault status

⚠️ Status

P2765 - Input/Turbine Shaft Speed Sensor B Circuit. The transmission control module has detected an open, short, no signal, or out-of-range reading on the Input/Turbine (Sensor B) circuit. This affects transmission shift control and torque converter operation.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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