P2E6B: System Too Rich During Cylinder Deactivation Bank 2

What it means

During cylinder deactivation on bank 2, the fuel trim of the active cylinders runs persistently rich. Indicates excess fuel delivery or injector leakage.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Cylinder deactivation shuts off selected cylinders while the remaining cylinders continue running. The control module monitors fuel-trim feedback from bank 2 when this mode is active. This code sets when the active cylinders on bank 2 run persistently richer than expected, often because an injector leaks or deactivation leaves residual combustion.

Common causes

Most likely first.

1. Injector leak on active cylinders
2. Deactivation partial - residual combustion

Symptoms

• Check engine light on
• Increased fuel consumption
• Black smoke from exhaust on acceleration
• Smell of unburned fuel, fouled spark plugs

How to diagnose it

1. Save freeze-frame data and compare bank 2 fuel trims in live data during deactivation and normal operation.
2. Check for fuel smell, black exhaust smoke, and related misfire codes, noting whether symptoms occur during acceleration or deactivation.
3. Inspect bank 2 spark plugs for fuel fouling and compare their condition with the manufacturer's diagnostic guidance.
4. Test bank 2 injectors for leakage and verify cylinder-deactivation operation using the manufacturer's procedure.
5. If injector and deactivation checks pass, assess bank 2 air-fuel sensor readings and circuit wiring.

Common fixes

• Replace a leaking bank 2 injector confirmed by testing.
• Repair the deactivation fault if a cylinder continues combusting when commanded off.
• Replace fuel-fouled spark plugs after the excess-fuel cause is corrected.
• Repair a bank 2 sensor circuit fault confirmed by testing.

Can I keep driving?

If you notice black smoke, strong fuel odor, or rough running, limit driving and avoid hard acceleration. Excess fuel can foul plugs and damage the catalytic converter; stop if misfiring is severe or the warning light flashes.