Input/Turbine Speed Sensor "B" Circuit Intermittent
The powertrain control module detected an erratic or intermittent voltage signal from the input/turbine speed sensor B circuit. This sensor measures transmission input shaft speed and is critical for proper shift timing and transmission control.
What You Might Notice
- Erratic or inaccurate speedometer reading
- Transmission fails to shift properly or shifts at wrong RPM
- Harsh or delayed transmission shifts
- Speedometer and/or odometer not operating
- Diminished fuel economy
Most Common Causes
- 1
Defective input speed sensor
The sensor itself has failed or is malfunctioning, causing erratic voltage signals to the PCM.
- 2
Damaged or corroded wiring harness
The 3-wire sensor connector or wiring has corrosion, breaks, or poor connections causing intermittent signal loss.
- 3
Faulty PCM or module connector
Poor connection at the PCM or internal module failure is preventing proper signal reception from the sensor.
- 4
Sensor installation issues
The sensor may be improperly installed, misaligned, or not fully seated in its bore, creating intermittent contact.
How to Diagnose It
- 1
Check Defective input speed sensor — The sensor itself has failed or is malfunctioning, causing erratic voltage signals to the PCM.
- 2
Check Damaged or corroded wiring harness — The 3-wire sensor connector or wiring has corrosion, breaks, or poor connections causing intermittent signal loss.
- 3
Check Faulty PCM or module connector — Poor connection at the PCM or internal module failure is preventing proper signal reception from the sensor.
- 4
Check Sensor installation issues — The sensor may be improperly installed, misaligned, or not fully seated in its bore, creating intermittent contact.
How to Fix It
- 1
Replace input speed sensor B
Remove and replace the defective input/turbine speed sensor B with an OEM or quality replacement part. Ensure proper installation depth and seating.
- 2
Inspect and repair sensor wiring harness
Carefully inspect the 3-wire sensor connector and harness for corrosion, breaks, or loose connections. Repair or replace damaged sections and ensure all connections are secure.
- 3
Check PCM connector and pins
Inspect the powertrain control module connector pins for corrosion or damage. Clean corroded pins and reseat the connector firmly to ensure proper signal transmission.
- 4
Clear code and perform test drive
After repairs, clear the diagnostic trouble code using a scan tool and perform a test drive to verify the transmission shifts properly and speedometer operates correctly.
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