Intermediate Shaft Speed Sensor B Circuit No Signal
The transmission control module is not receiving a signal from the intermediate shaft speed sensor B circuit. This sensor monitors transmission shaft speed to enable proper gear shifting and transmission operation. Without this signal, the transmission cannot shift correctly and driveability suffers.
What You Might Notice
- Hard or delayed gear shifts
- Erratic engine speed or hunting between gears
- Poor overall driveability
- Multiple warning lights illuminated on dashboard
- Transmission stuck in limp mode or failsafe gear
Most Common Causes
- 1
Defective intermediate shaft speed sensor
The sensor itself may be faulty, failed electrically, or mechanically damaged. This is the most common cause of P2747.
- 2
Wiring or connector issues
Corroded, loose, or damaged wires and connectors between the speed sensor and transmission control module prevent signal transmission.
- 3
Low or dirty transmission fluid
Degraded automatic transmission fluid can cause sensor malfunction and internal transmission component wear that affects speed signal accuracy.
- 4
Transmission control module fault
An internal ECM or TCM malfunction may prevent proper reception or processing of the speed sensor signal despite the sensor functioning.
How to Diagnose It
- 1
Check Defective intermediate shaft speed sensor — The sensor itself may be faulty, failed electrically, or mechanically damaged. This is the most common cause of P2747.
- 2
Check Wiring or connector issues — Corroded, loose, or damaged wires and connectors between the speed sensor and transmission control module prevent signal transmission.
- 3
Check Low or dirty transmission fluid — Degraded automatic transmission fluid can cause sensor malfunction and internal transmission component wear that affects speed signal accuracy.
- 4
Check Transmission control module fault — An internal ECM or TCM malfunction may prevent proper reception or processing of the speed sensor signal despite the sensor functioning.
How to Fix It
- 1
Replace intermediate shaft speed sensor
Locate the intermediate shaft speed sensor on the transmission, disconnect the electrical connector, remove the mounting bolt, and install the new sensor. Reconnect the connector and clear the fault code.
- 2
Inspect and repair wiring harness
Check all wires and connectors between the speed sensor and transmission control module for corrosion, damage, or loose connections. Repair or replace damaged sections and reseat all connectors firmly.
- 3
Change transmission fluid and filter
Drain the old automatic transmission fluid, replace the transmission filter, and refill with the correct fluid type for your vehicle. This restores sensor function and transmission operation.
- 4
Test or reprogram transmission control module
If other repairs do not resolve the code, have a professional diagnose the TCM with specialized diagnostic equipment. The module may require reprogramming or replacement.
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