Powertrain, generic · Transmission

P07AB Transmission Friction Element E Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Each friction element (clutch or brake) has three functional codes: slip while commanded locked (P079A ff), performance/stuck off – it does not apply or applies too weakly – and stuck on – it does not release. GM's hybrid transmissions use only the stuck-on codes: when a clutch should release, the module expects slip to build and flags it if slip stays near zero – here only the Cadillac CT6 plug-in, whose transmission has a fifth clutch: it compares actual slip with the target release profile or detects missing slip while releasing, 2 s, after one trip. No other manufacturer document available to us uses it.

Likely causes

Clutch E stuck, welded or piston hanging
Valve or spool sticking in the applied position
Contaminated fluid (debris)
Module software

Symptoms

  • Check engine light or 'service hybrid system' message
  • Jolt or tie-up on mode or gear changes
  • Engine stalls or drags when stopping
  • Limp mode with reduced power

Repair estimate

DifficultyHardWorkshop job
Parts and labour€200–4,500
Time1–12 h

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

Parts involved

transmission clutchestransmission valve bodyhybrid control module

Related codes

P07AAP079EP07A9P2704

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.