Powertrain, generic · Transmission

P07A7 Transmission Friction Element C 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 – the Two-Mode at 80 rpm or less for 4.5 s with more than 140–200 Nm, after two trips; Volt Gen 1 and ELR when the target is above 360 rpm but actual slip stays below 100 rpm, after one trip. On the Volt Gen 2 clutch 3 is a one-way clutch: stuck on means it locks where it should freewheel (0.38 s, one trip). The Malibu Hybrid has no clutch 3.

Likely causes

Clutch C 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

P07A6P079CP07A5P2702

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.