A leaking or dripping fuel injector on a cylinder in bank 2 that is active during deactivation; Fuel pressure regulator or high-pressure fuel pump delivering more pressure than commanded; A stuck-open or contaminated purge valve allowing fuel vapor to be drawn into the intake; A biased or slow-responding oxygen sensor on bank 2 giving false rich feedback; An intake or exhaust leak that skews the air-fuel calculation specifically during deactivation; A faulty cylinder deactivation oil control solenoid or lifter that disrupts combustion in the deactivated cylinders; A software calibration issue in the powertrain control module affecting deactivation fueling strategy

DTC codes / P2Exx · Hybrid propulsion / P2E6B

P2E6BSystem Too Rich During Cylinder Deactivation Bank 2

Q: What does code P2E6B mean?

System Too Rich During Cylinder Deactivation Bank 2. P2E6B means the powertrain control module has detected an excessively rich air-fuel mixture on bank 2 while cylinder deactivation is active, meaning that bank is receiving more fuel than the computer commanded. The computer compares its fueling calculations against oxygen sensor feedback and flags the code when the measured rich condition exceeds the calibrated threshold during the deactivation window.

P2E6B means the powertrain control module has detected an excessively rich air-fuel mixture on bank 2 while cylinder deactivation is active, meaning that bank is receiving more fuel than the computer commanded. The computer compares its fueling calculations against oxygen sensor feedback and flags the code when the measured rich condition exceeds the calibrated threshold during the deactivation window.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
A slight stumble or roughness when the engine transitions into or out of cylinder deactivation mode
Noticeably worse fuel economy than normal over a tank of fuel
Black sooty exhaust smoke or a strong raw fuel smell at the tailpipe
Elevated hydrocarbon readings or a failed emissions test
In severe cases, a flashing check engine light accompanied by misfire codes

Common causes, most likely first

A leaking or dripping fuel injector on a cylinder in bank 2 that is active during deactivation
Fuel pressure regulator or high-pressure fuel pump delivering more pressure than commanded
A stuck-open or contaminated purge valve allowing fuel vapor to be drawn into the intake
A biased or slow-responding oxygen sensor on bank 2 giving false rich feedback
An intake or exhaust leak that skews the air-fuel calculation specifically during deactivation
A faulty cylinder deactivation oil control solenoid or lifter that disrupts combustion in the deactivated cylinders
A software calibration issue in the powertrain control module affecting deactivation fueling strategy

How to diagnose and fix it

Scan all modules for stored and pending codes and record freeze-frame data to confirm the conditions under which P2E6B sets
Inspect the bank 2 oxygen sensor signal and fuel trim values with a scan tool while commanding cylinder deactivation on and off
Check fuel pressure and compare it to the manufacturer's specification, looking for a regulator or pump that over-delivers
Test the evaporative emissions purge valve for sticking open and verify it seals when commanded closed
Perform an injector balance or leak-down test on the bank 2 injectors to identify a dripping or stuck-open injector
Smoke-test the intake and exhaust for leaks that could distort the mixture calculation during deactivation
Verify the cylinder deactivation solenoids and lifters are functioning correctly and reflash the powertrain control module if a calibration update is available

Why deactivation-only rich codes mislead

A rich condition that appears only during cylinder deactivation often points to an injector that leaks when its cylinder is reactivated, not to a general fueling fault across the whole bank.
Technicians frequently replace oxygen sensors based on a rich code when the sensor is accurately reporting a genuine over-fueling condition caused by a purge valve or injector.
Cylinder deactivation changes airflow and exhaust pulse patterns, so an exhaust leak that is harmless at full cylinder operation can skew the bank 2 oxygen sensor reading only while cylinders are deactivated.
A failing oil control solenoid for the deactivation lifters can leave a cylinder partially active, creating an uncommanded rich exhaust pulse that the computer interprets as a bank-wide rich condition.
This code does not always mean the engine is running dangerously rich at all times; it may only set during specific deactivation windows, so a road test with live data is essential before condemning parts.

Can I keep driving with P2E6B?

You can usually drive the vehicle to a repair shop, but avoid heavy acceleration and long trips until the fault is diagnosed, because prolonged rich operation can overheat and damage the catalytic converter. If the check engine light flashes or the engine runs rough, stop driving and arrange a tow.

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.