P094A: Hydraulic Pump Driver Performance

What it means

The hydraulic pump reports a driver performance condition. Pump operation is impaired.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The hydraulic pump driver is the electronic output that controls pump operation, and the TCM monitors whether the driver responds as expected. P094A sets when pump-driver performance is outside the expected range, which may reflect output-driver drift or a high-resistance connection.

Common causes

Most likely first.

1. Output driver characteristic drifted
2. High-resistance contact

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

1. Record freeze-frame data and scan for related pump, relay, and pressure codes to see whether the driver fault coincides with a pump command.
2. Inspect the pump driver and harness connectors for loose terminals, corrosion, heat damage, or water intrusion.
3. Check the wiring between the driver and hydraulic pump for damage or high-resistance connections.
4. Measure the driver circuit response during a pump command and compare it with the manufacturer's specification.
5. If wiring and connections pass, test the driver output and pump load using the manufacturer's diagnostic procedure to distinguish a driver fault from a pump fault.

Common fixes

• Repair loose, corroded, or damaged pump-driver wiring and connections.
• Repair a high-resistance terminal or harness section.
• Replace the hydraulic pump driver if its output fails testing.
• Repair or replace the pump if testing shows that it is overloading the driver.

Can I keep driving?

Avoid towing or demanding driving because impaired pump control can lead to poor shifts or limp mode. Stop if the transmission slips, loses drive, or shifts unpredictably.