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P2797 — Electricauxiliary Transmission Fluid Pump Performancestuck Off

Manufacturer-specificPowertrain (engine & transmission)

The P2797 code indicates that the Powertrain Control Module (PCM) has detected that the electric auxiliary transmission fluid pump is not operating when commanded. This pump is typically used to maintain fluid pressure and cooling during specific operating conditions.

Symptoms

What causes it — most likely first

1. Auxiliary Pump Failure

The electric pump motor has suffered an internal electrical failure or mechanical seizure.

2. Wiring Harness Issues

Corroded connectors, frayed wires, or open circuits between the PCM and the pump.

3. Blown Fuse or Failed Relay

A loss of power supply to the pump due to a blown fuse or a malfunctioning relay.

4. PCM Malfunction

The control module is failing to send the trigger signal to activate the pump.

How it's diagnosed

  1. Retrieve all stored diagnostic trouble codes to see if other transmission or electrical codes are present.
  2. Inspect the dedicated fuse and relay for the auxiliary transmission pump for continuity.
  3. Use a multimeter to verify that the pump connector receives the correct voltage and ground when the PCM commands the pump on.
  4. Measure the electrical resistance of the pump motor terminals to check for internal shorts or open windings.
  5. Inspect the wiring harness for physical damage, corrosion, or signs of rodent interference.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is it safe to drive with P2797?

The vehicle is usually drivable, but the lack of auxiliary fluid flow can lead to overheating or increased wear on transmission components over time.

Does this code mean the entire transmission needs to be replaced?

No, P2797 specifically refers to the auxiliary pump, which is a separate electrical component and does not necessarily indicate a total transmission failure.

Should I replace the PCM if I have this code?

No. The PCM is the least likely cause of this fault. The pump itself or the electrical circuit should be thoroughly tested before considering a module replacement.