What it means
The control module detects a high electrical level in the pressure control solenoid A control circuit. This indicates an electrical circuit fault; it does not by itself confirm a short to power or an open winding.
At a glance
- Usually lights the check-engine light
How it works
Pressure control solenoid A is an electrically operated valve that helps regulate hydraulic pressure in the transmission. The control module monitors the electrical level in solenoid A’s control circuit and sets P0963 when it detects a level above its expected range. This indicates a circuit fault, but does not by itself establish whether the cause is a short to power or an open coil.
Common causes
Most likely first.
- Short to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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 for when the fault occurs and whether solenoid A is being commanded.
- Inspect solenoid A’s connector and harness for corrosion, pin damage, chafing, or a wire pinched against a power source.
- With the circuit safely isolated as specified by the manufacturer, check whether solenoid A’s control wire is unintentionally connected to battery power.
- Check connector pin fit and circuit continuity, then measure solenoid A coil resistance against the manufacturer’s specification.
- If the coil and wiring pass, test the control module’s solenoid A driver and connections using the manufacturer’s procedure.
Common fixes
- Clean and secure corroded or loose solenoid A connector terminals.
- Repair a control wire shorted to power or pinched against a power source.
- Replace pressure control solenoid A if its coil fails resistance or functional testing.
- Repair the control module connection or driver only if circuit testing confirms a module fault.
Can I keep driving?
Avoid hard acceleration, towing, and unnecessary driving if shifts are harsh, delayed, slipping, or the transmission enters limp mode, since abnormal pressure control can increase wear. If it will not shift reliably, stop somewhere safe and arrange assistance.
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.