What it means
Voltage on the clutch B pressure sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
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 measures hydraulic pressure in clutch B, and the transmission control module reads its signal to manage clutch engagement. This code sets when the signal rises above its expected range, consistent with a signal circuit short to battery voltage or an open sensor circuit.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open pressure sensor
- 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
- Save freeze-frame data and compare clutch B pressure with clutch commands to establish whether the high reading is constant or occurs during a shift.
- Inspect the clutch B pressure sensor connector and harness for corrosion, loose or backed-out pins, and damage that could connect the signal to battery voltage.
- Check sensor supply, ground, and signal wiring against the manufacturer's specification, looking for a short to B+ or an open circuit.
- If wiring continuity and connector condition are acceptable, test the clutch B pressure sensor output and circuit response against the manufacturer's specification.
- Repair the identified open, short, or sensor fault, then clear the code and confirm plausible clutch B pressure data during shifts.
Common fixes
- Clean and secure corroded or loose sensor connector pins.
- Repair the clutch B pressure signal wire shorted to B+.
- Repair an open in the sensor circuit or its wiring.
- Replace the clutch B pressure sensor if it fails testing.
Can I keep driving?
Avoid driving if the transmission shifts harshly, slips, misses shifts, or enters limp mode; an implausible clutch B pressure reading can disrupt clutch control and slipping may worsen transmission damage. If it drives normally, keep any trip short and gentle until diagnosed.
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.