Powertrain, generic (extended)

P2797 Electric/Auxiliary Transmission Fluid Pump A Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2797 says pump A was asked to deliver but no useful pressure resulted. GM checks this on CVTs during an engine auto-start: with the pump commanded and over 400 kPa requested at both pulleys, both pressure sensors reading under 200 kPa for more than 0.525 s set the Type B code. GM bulletin 19-NA-200 (Malibu 2019–2025, Trailblazer, Encore GX, 2025 Equinox) blames an internal pump failure and replaces pump and harness. Subaru found false detections on 2023–2024 Legacy and Outback 2.4 turbo CVTs, caused by forward clutch engagement at restart, and released TCM files (16-145-23R). Stellantis traces P2797 on some 2026 Charger, Grand Cherokee and Wagoneer models with the 880RE eight-speed to a failed oil pump motor (21-053-26). Stop-start is usually the first casualty.

Likely causes

Internal failure of the auxiliary pump or its motor
Control software misjudging pump output (TCM update available)
Damaged pump wiring harness
Low fluid or internal leakage preventing pressure build-up

Symptoms

  • MIL on
  • Stop-start inoperative
  • Shock or surge when the engine restarts at a stop
  • Service transmission message

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€0–2,500
Time0.5–8 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

aux trans pump apump motor

Related codes

P2796P2798P2799P27A1P27A3P0B0C

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.