P2E68 code meaning
System Too Lean During Cylinder Deactivation Bank 1
Powertrain system Generic code P2Exx codes Check engine light
What P2E68 means
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.
P2E68 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 8 hours
- Clears after repairAfter a drive cycle
Symptoms of P2E68
- 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
Common causes of P2E68
- Most 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
- Less likelyBank 1 oxygen sensor reading biased rich
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel injectorsDeactivation solenoidsIntake system
What each part of P2E68 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 68 | The exact fault in that area. |
What to do next
- Note P2E68 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2E68
What does P2E68 mean?
P2E68 means "System Too Lean During Cylinder Deactivation Bank 1". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2E68?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2E68 fail an emissions test?
Yes, it can. P2E68 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2E68 to fix?
Difficulty: hard. A typical repair takes 1 to 8 hours of work. This is a job for a workshop.
Will P2E68 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.