What it means
The second auxiliary transmission fluid pump motor has reached over-temperature. Sustained high duty or insufficient cooling.
At a glance
- Usually lights the check-engine light
How it works
The electric motor in auxiliary transmission fluid pump B operates when the transmission needs additional fluid circulation or hydraulic support. The control module monitors the pump motor's temperature and sets this code when it exceeds its operating limit, which may follow sustained high demand or restricted cooling.
Common causes
Most likely first.
- Sustained high duty cycle
- Cooling air or fluid path blocked
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
- Read freeze-frame data and pump B temperature, command, and operating data to determine whether overheating followed sustained operation or a particular event.
- Inspect pump B and its surrounding area for blocked cooling airflow, accumulated debris, or a restricted fluid path.
- Check the pump B connector and wiring for heat damage, poor connections, or faults that could cause excessive motor effort.
- After the system has cooled, compare pump operation and temperature behavior with the manufacturer's diagnostic procedure to see whether the motor overheats again under normal demand.
- If cooling and wiring are sound, test pump B and its fluid path for excessive load or restricted circulation.
Common fixes
- Clear debris or obstruction from the pump's cooling airflow or fluid path.
- Repair heat-damaged wiring or a poor pump B electrical connection.
- Correct a restriction that makes pump B work excessively hard.
- Replace pump B if it overheats again despite normal cooling and a sound circuit.
Can I keep driving?
If the transmission is shifting normally and the warning is not accompanied by slipping or loss of drive, avoid heavy loads and let the system cool before continuing cautiously. Stop if shifting becomes abnormal; repeated overheating can damage the pump and impair transmission pressure.
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.