What it means
During cylinder deactivation on bank 2, the fuel trim of the active cylinders runs persistently lean. Indicates unmetered air ingress or fuel delivery shortfall.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Cylinder deactivation temporarily shuts off selected cylinders so the remaining cylinders can keep the engine running. The control module monitors fuel-trim feedback from bank 2 during deactivation. This code sets when the active cylinders on bank 2 require persistently more fuel than expected, pointing to unmetered air or a fuel-delivery shortfall.
Common causes
Most likely first.
- Vacuum leak unmasked during deactivation
- Fuel rail pressure low
Symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
How to diagnose it
- Record freeze-frame data and compare bank 2 fuel trims during normal running and cylinder deactivation with a scan tool.
- Check for related misfire or air-fuel sensor codes and determine whether hesitation or roughness coincides with deactivation.
- Inspect bank 2 intake and vacuum hoses for leaks that could create a lean mixture on that side.
- Measure fuel pressure under the conditions specified by the manufacturer to check for inadequate rail pressure.
- If no air leak or pressure fault is found, test bank 2 sensor readings and injector delivery using the manufacturer's procedure.
Common fixes
- Repair a vacuum or intake leak affecting bank 2.
- Replace a damaged or disconnected hose admitting unmetered air.
- Correct low fuel pressure after locating the fuel-delivery fault.
- Repair a bank 2 sensor or injector problem confirmed by testing.
Can I keep driving?
Rough running, hesitation, or stalling can make driving unsafe, so avoid heavy loads and high-speed trips until diagnosed. A persistent lean condition can worsen drivability and may harm the engine or exhaust components.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.