What it means
The control system detects that the pump A driver is not controlling pump operation as expected. The exact cause may involve the driver, pump load, or their electrical connection.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The pump A driver controls power to the auxiliary transmission fluid pump, which helps maintain hydraulic pressure for shifting. The control module monitors whether the driver responds as expected when pump A is commanded. This performance code can reflect a driver that is not controlling the pump properly, excessive pump load, or a fault in the connection between them.
Common causes
Most likely first.
- Faulty pump driver
- Excessive pump load
- Pump wiring or connector fault
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 review live data for pump A commands, driver status, and any reported current or speed when the fault occurred.
- Inspect pump A's connector and the wiring between the pump and its driver for loose pins, corrosion, damaged insulation, or signs of overheating.
- Check transmission fluid level and condition using the manufacturer's procedure, since an abnormal pump load can affect driver performance.
- If the scan tool supports it, command pump A on and observe whether the driver responds and the pump operates consistently.
- Test the pump A power and control circuits for opens, shorts, and excessive resistance according to the manufacturer's procedure.
- If the circuit and pump load test normally, diagnose the pump A driver for a control or output fault.
Common fixes
- Repair damaged wiring or poor connections at pump A or its driver.
- Correct transmission fluid level or condition if it is outside the manufacturer's requirements.
- Replace pump A if testing confirms excessive load or inconsistent operation.
- Repair or replace the pump driver if circuit and pump checks show that it is not controlling pump A correctly.
Can I keep driving?
Avoid driving if the transmission slips, shifts harshly or late, or enters limp mode; inadequate pump control can lead to loss of drive or further transmission damage. If symptoms are absent, keep driving to a minimum until the fault is 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.