P07AB: Transmission Friction Element E Stuck On

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.

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

Most likely causes

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

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition
2. Use the scanner to command the movement and compare the actual position with the requested one.
3. Read the input and output speed in live data
4. Check the connector and wiring
5. Check for other related engine codes
6. Consult the manufacturer's procedure for the transmission

Good to know

• Repair difficulty: hard
• It can trigger limp mode.
• It affects emissions.

What each character of P07AB means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 7: Transmission
• AB: Specific fault in that system

Frequently asked questions

Can I keep driving with code P07AB?

Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.

What causes code P07AB?

The most common causes are: clutch E stuck, welded or piston hanging; valve or spool sticking in the applied position; contaminated fluid (debris).

Related codes

• P07AATransmission Friction Element E Performance/Stuck Off
• P079ETransmission Friction Element E Slip Detected
• P07A9Transmission Friction Element D Stuck On
• P2704Transmission Friction Element E Apply Time Range/Performance

Sources

• gsi.ext.gm.com: 18OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 2018 OBD GROUP SUMMARY
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.