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P2798 Powertrain

P2798 — Electric/Auxiliary Transmission Fluid Pump A Control Circuit Low

Voltage on the first auxiliary transmission fluid pump control line is below the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.

Affected components

  • Aux trans pump a
  • Wiring harness

Possible causes to check

These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.

  • Control wire shorted to ground
  • Motor winding short
  • Connector pins corroded - high contact resistance

Possible 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

Diagnostic notes

  • The malfunction indicator lamp may illuminate

Related codes

Sources

Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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