What it means
The transmission control module monitors the control circuit for pressure control solenoid B. It sets this code when it detects an open circuit in the solenoid’s driver circuit.
At a glance
- Usually lights the check-engine light
How it works
Pressure control solenoid B is an electrically operated valve that helps regulate transmission hydraulic pressure. The transmission control module monitors solenoid B’s driver circuit and sets P0964 when it detects an open circuit. The cause may be an open solenoid coil, a poor or displaced connector pin, damaged wiring, or a fault in the module’s driver path.
Common causes
Most likely first.
- Solenoid coil open
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
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 check transmission live data to see when the solenoid B circuit fault occurred and what the module commanded.
- Inspect solenoid B’s connector and harness for a pushed-back pin, corrosion, loose terminals, or broken wiring.
- Check the solenoid B coil and its circuit continuity against the manufacturer’s specification to locate an open.
- If accessible under the manufacturer’s procedure, inspect the transmission connector and internal harness for an open between the external connector and solenoid B.
- If the coil and harness are intact, test the control module connector and solenoid B driver circuit for an open or internal connection fault.
Common fixes
- Reseat or replace a displaced or damaged solenoid B connector terminal.
- Repair an open or broken wire in the solenoid B circuit.
- Replace pressure control solenoid B if its coil is open.
- Repair the control module connection or driver only if testing confirms an internal fault.
Can I keep driving?
Limit driving if the transmission shifts harshly, slips, delays engagement, or becomes stuck in one gear; a control fault can make the vehicle unpredictable and increase transmission wear. Arrange assistance if it cannot shift safely.
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.