What it means
The TCM cannot read a valid signal from the clutch B motor rotor position sensor. Open wiring or sensor failure.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The clutch B motor has a rotor-position sensor that tells the transmission control module where the motor is so it can switch the U, V and W phases at the right time. This code sets when the module cannot obtain a valid position signal, often because the signal circuit is open, a connector pin is displaced or the sensor has failed.
Common causes
Most likely first.
- Open in sensor signal wire
- Position sensor failed
- Pin pushed back out of connector body
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Capture freeze-frame data and check clutch B position-sensor data and related motor faults to confirm whether the signal is absent or intermittent.
- Inspect the position-sensor connector for a pin pushed back into the body, corrosion, poor fit or fluid intrusion.
- Trace the sensor signal wire and its associated wiring for breaks, chafing or damage between the sensor and transmission control module.
- With power isolated as directed by the manufacturer's procedure, test signal-wire continuity and connector terminal contact through the full circuit.
- If the wiring passes, test the position sensor and its supply and ground circuits using the manufacturer's specification.
Common fixes
- Reseat a pushed-back position-sensor terminal and secure the connector.
- Repair an open or damaged sensor signal wire.
- Clean or replace corroded sensor connector terminals.
- Replace the clutch B motor position sensor if it fails the specified test.
Can I keep driving?
Avoid driving if shifting is delayed, harsh or slipping, because the transmission may lose reliable control of clutch B and enter limp mode. If the vehicle remains driveable, limit the trip and stop if it loses a gear or shift behavior becomes unpredictable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.