P2E68System Too Lean During Cylinder Deactivation Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2E68 is a fuel trim fault that is judged only while cylinders are shut off: in that mode bank 1 needs more fuel correction than allowed. GM uses it on its 4.2-litre twin-turbo V8 (LTA, table 19OBDG07): the engine learns a separate multiplicative long-term trim for deactivation mode, and the code sets when that factor for bank 1 rises above 1.23 and has been steady for at least 10 s; Type B, MIL after two trips. Enables include coolant at 54.8 °C or more, intake air under 90 °C and no wide-open throttle. Full-engine lean faults use other codes, such as P2177. On that engine half the cylinders run in this mode, two per bank. A Ford patent explains why a faulty valve deactivator shows up as a bank-specific trim shift.
- What you may notice
- Check engine light after two trips
- Slight shake or surge at light cruise when cylinders are shut off
- Cylinder deactivation may be used less often
- Likely causes
- LikelyRestricted injector on one of the cylinders that keep firing on bank 1
- PossibleUnmetered air entering bank 1 (intake leak, seal, PCV)
- PossibleDeactivating rocker or lifter on bank 1 not holding the valves shut, pumping air into the exhaust
- RareBank 1 oxygen sensor reading biased rich
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.