Leaking or dripping fuel injector on one of the deactivated cylinders; Faulty or contaminated oxygen sensor on bank 1 giving a false rich reading; Sticking or leaking purge valve allowing fuel vapor into the intake when it should be closed; High fuel pressure from a failing pressure regulator or restricted return line; Intake or exhaust leaks upstream of the oxygen sensor that skew mixture feedback; Worn spark plugs or ignition components causing incomplete combustion on the affected bank; Engine oil consumption or crankcase ventilation issues adding fuel-like hydrocarbons to the intake

DTC codes / P2Exx · Hybrid propulsion / P2E69

P2E69System Too Rich During Cylinder Deactivation Bank 1

Q: What does code P2E69 mean?

System Too Rich During Cylinder Deactivation Bank 1. P2E69 means the powertrain control module has detected an excessively rich air-fuel mixture on bank 1 while cylinder deactivation is active, typically during light-load cruising. The computer compares commanded fuel delivery against oxygen sensor feedback and flags the bank as rich when fuel trims go too negative or the sensor stays high for too long.

P2E69 means the powertrain control module has detected an excessively rich air-fuel mixture on bank 1 while cylinder deactivation is active, typically during light-load cruising. The computer compares commanded fuel delivery against oxygen sensor feedback and flags the bank as rich when fuel trims go too negative or the sensor stays high for too long.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms
A slight stumble or hesitation when the engine transitions in or out of cylinder deactivation mode
Reduced fuel economy, especially on steady highway drives where deactivation is most active
Black sooty exhaust or a strong fuel smell at the tailpipe
Rough idle or misfire-like shudder that may clear when all cylinders are reactivated
In some cases, the engine may refuse to enter cylinder deactivation mode at all

Common causes, most likely first

Leaking or dripping fuel injector on one of the deactivated cylinders
Faulty or contaminated oxygen sensor on bank 1 giving a false rich reading
Sticking or leaking purge valve allowing fuel vapor into the intake when it should be closed
High fuel pressure from a failing pressure regulator or restricted return line
Intake or exhaust leaks upstream of the oxygen sensor that skew mixture feedback
Worn spark plugs or ignition components causing incomplete combustion on the affected bank
Engine oil consumption or crankcase ventilation issues adding fuel-like hydrocarbons to the intake

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code sets only during cylinder deactivation
Inspect live fuel trim and oxygen sensor data on bank 1 while commanding deactivation on and off
Check for intake and exhaust leaks with a smoke test before condemning any sensor
Test the purge valve for sticking or leakage and verify it seals when commanded closed
Measure fuel pressure and compare against specification, looking for excessive pressure
Perform an injector balance or leak-down test on the cylinders that deactivate
Replace the confirmed faulty component and clear the code, then verify fuel trims return to normal

Cylinder deactivation rich codes misdiagnosed often

A rich code that only appears during cylinder deactivation frequently points to an injector that leaks when its cylinder is cut off, not a failed oxygen sensor.
Technicians often replace the upstream oxygen sensor first, but a contaminated sensor usually sets a heater or response code alongside the rich code.
A sticking purge valve can deliver fuel vapor into the intake only at certain vacuum levels, mimicking a deactivation-specific rich condition.
Oil consumption on engines with cylinder deactivation can foul plugs and skew mixture on the deactivated bank, so check oil level and plug condition.
The code does not always mean the engine is running dangerously rich; a lazy oxygen sensor can report rich when the mixture is actually correct.

Can I keep driving with P2E69?

You can usually drive the vehicle to a repair shop, but avoid heavy loads and long highway trips that keep cylinder deactivation active. Continued driving with a genuinely rich mixture can foul spark plugs and damage the catalytic converter over time.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.