What it means
Voltage on the clutch B pressure sensor signal line is below the expected window. Wire shorted to ground or sensor short.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The clutch B pressure sensor reports hydraulic pressure in clutch B to the transmission control module. The module monitors the sensor signal and sets this code when it falls below the expected range, which can make the module misjudge clutch B pressure during shifts.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
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
- Record freeze-frame data and compare clutch B pressure readings with clutch commands and other transmission data to see when the signal drops.
- With the ignition off, inspect the clutch B pressure sensor connector and harness for corrosion, damaged insulation, or a signal wire contacting ground.
- Check the sensor supply, ground, and signal wiring against the manufacturer's specification, paying particular attention to an unintended ground on the signal circuit.
- If the wiring and connector are sound, test the clutch B pressure sensor output against the manufacturer's specification under the conditions that set the code.
- Repair the confirmed wiring or sensor fault, then clear the code and verify clutch B pressure readings and shift operation.
Common fixes
- Clean and secure corroded or loose clutch B pressure sensor connector pins.
- Repair a signal wire shorted to ground.
- Replace a clutch B pressure sensor confirmed internally shorted.
- Clear the code and verify normal clutch B pressure readings and shifts.
Can I keep driving?
If shifts are harsh, delayed, slipping, or the transmission enters limp mode, avoid continued driving and arrange a safe stop; clutch B pressure may be controlled incorrectly and further slipping can damage the transmission. If symptoms are absent, limit driving to a short trip for diagnosis and avoid heavy loads.
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.