P2E69: System Too Rich During Cylinder Deactivation Bank 1

What it means

During cylinder deactivation on bank 1, 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 keep producing power. The control module monitors fuel-trim feedback from bank 1 during this mode. This code sets when the active cylinders on bank 1 run persistently richer than expected, which can result from leaking injectors or cylinders that continue combusting when deactivation is partial.

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 1 fuel trims during deactivation and normal operation using live scan data.
2. Check for black smoke, fuel smell, and related misfire codes, and note whether these appear during acceleration or deactivation.
3. Inspect bank 1 spark plugs for fuel fouling and compare their condition with the manufacturer's diagnostic guidance.
4. Test bank 1 injectors for leakage and verify that deactivated cylinders stop combusting as commanded using the manufacturer's procedure.
5. If injectors and deactivation operation check out, assess bank 1 air-fuel sensor readings and wiring.

Common fixes

• Replace a leaking bank 1 injector confirmed by testing.
• Repair the cylinder-deactivation fault if a cylinder continues combusting when commanded off.
• Replace fuel-fouled spark plugs after correcting the cause.
• Repair a faulty bank 1 sensor circuit if testing identifies it.

Can I keep driving?

Limit driving, especially under acceleration, if there is black smoke, a strong fuel smell, or rough running. Excess fuel can foul plugs and damage the catalytic converter; stop if the engine misfires severely or the warning light flashes.