What it means
The motor supply line of the second electric or auxiliary transmission fluid pump is open. Pump cannot run, hydraulic pressure is lost during stop-start engine-off events.
At a glance
- Usually lights the check-engine light
How it works
Electric or auxiliary transmission fluid pump B supplies hydraulic pressure when the transmission needs pump assistance, such as during engine-off operation in some stop-start systems. P276A sets when the pump B motor’s supply circuit is open, so the pump cannot receive power.
Common causes
Most likely first.
- Blown fuse on supply line
- Broken supply wire
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
- Review freeze-frame data and check pump B command and status to confirm when the supply fault occurs.
- With the vehicle safely powered down, inspect pump B’s fuse and its supply wiring for visible damage.
- Check the fuse and supply path for continuity, following the vehicle wiring diagram.
- Inspect pump B’s connector for looseness, corrosion, or damaged terminals.
- If the supply path is intact, test voltage at the pump B motor feed when commanded, using the manufacturer's specification.
Common fixes
- Replace a blown pump B supply fuse after checking for a short or overload.
- Repair a broken pump B supply wire.
- Clean and secure the pump B connector or repair damaged terminals.
- Replace pump B if the correct supply reaches it but the motor does not operate.
Can I keep driving?
Avoid relying on engine-off stop-start operation, and limit driving if shifts are delayed, slipping, or the transmission enters limp mode. Loss of auxiliary pump pressure can impair transmission operation when that pump is needed.
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.