Transmission Range Sensor "B" Circuit High
The transmission range sensor B circuit is reading a voltage that is higher than expected, preventing the transmission control module from correctly identifying the gear selector position. This causes the transmission to default to an incorrect gear (often third), resulting in severe loss of power and potential transmission damage if driving continues.
What You Might Notice
- Check engine light illuminated
- Severe lack of power during acceleration from a stop
- Transmission starting in third gear instead of park/drive/neutral
- Difficulty shifting or erratic gear selection
- Transmission slipping or harsh shifting
Most Common Causes
- 1
Faulty transmission range sensor B
The sensor itself has failed electrically, causing it to send an abnormally high voltage signal to the transmission control module.
- 2
Damaged wiring or connector corrosion
Corroded pins, loose connectors, or damaged wiring in the sensor circuit can cause high voltage readings and signal loss to the TCM.
- 3
Misadjusted transmission shift cable or linkage
If the shift cable or linkage is misaligned, the sensor may not be in the correct position for the selected gear, sending incorrect signals.
- 4
Transmission control module (TCM) or PCM failure
A faulty transmission or powertrain control module may misinterpret sensor signals or fail to communicate properly with the range sensor circuit.
How to Diagnose It
- 1
Check Faulty transmission range sensor B — The sensor itself has failed electrically, causing it to send an abnormally high voltage signal to the transmission control module.
- 2
Check Damaged wiring or connector corrosion — Corroded pins, loose connectors, or damaged wiring in the sensor circuit can cause high voltage readings and signal loss to the TCM.
- 3
Check Misadjusted transmission shift cable or linkage — If the shift cable or linkage is misaligned, the sensor may not be in the correct position for the selected gear, sending incorrect signals.
- 4
Check Transmission control module (TCM) or PCM failure — A faulty transmission or powertrain control module may misinterpret sensor signals or fail to communicate properly with the range sensor circuit.
How to Fix It
- 1
Replace transmission range sensor B
Remove and replace the faulty sensor with a manufacturer-approved part, then verify proper voltage output and reprogram the TCM if necessary.
- 2
Inspect and repair wiring and connectors
Clean corroded connectors, repair damaged wiring, and ensure all connections are secure. Test voltage at the sensor connector to confirm proper circuit operation.
- 3
Adjust transmission shift cable and linkage
Verify that the shift cable and mechanical linkage are properly aligned with the sensor. Adjust according to manufacturer specifications to ensure the sensor reads the correct gear position.
- 4
Test and reprogram TCM or PCM
After repairs, use a professional diagnostic scanner to clear codes, verify sensor signals, and reprogram the transmission or powertrain control module if needed.
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