What it means
Fuel control system B on bank 2 has detected a lean condition at idle. The code identifies the operating condition and fuel control system; it does not specify a particular cause.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Fuel control system B adjusts fueling for bank 2 using sensor feedback while the engine idles. This code sets when the system detects bank 2 running lean at idle, a condition often caused by extra air entering through a bank 2 intake leak, PCV path, or purge valve.
Common causes
Most likely first.
- Vacuum leak near bank 2 intake
- Intake manifold gasket leak
- PCV system leak or fault
- Purge valve stuck open
- Faulty air-fuel ratio or oxygen sensor
Symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
How to diagnose it
- Save freeze-frame data and inspect bank 2 fuel trims and air-fuel or oxygen sensor readings at idle to confirm the operating condition.
- Inspect bank 2 intake connections, vacuum hoses, and manifold gasket area for air leaks that can have a strong effect at idle.
- Check the PCV system for leaking hoses or a faulty valve, then assess whether the purge valve is allowing flow at idle.
- Compare bank 2 fuel trims with bank 1 at idle and at a raised speed to see whether the lean correction is isolated to bank 2.
- If air paths are intact, test bank 2 sensor response and wiring according to the manufacturer's diagnostic information.
Common fixes
- Repair a leaking bank 2 vacuum hose or intake connection.
- Repair a leaking intake manifold gasket affecting bank 2.
- Repair a PCV leak or replace a purge valve that passes flow at idle.
- Repair wiring or replace a bank 2 sensor only if it fails the specified response test.
Can I keep driving?
If the engine maintains a steady idle, make only a short, gentle trip for diagnosis and avoid heavy loads. Do not continue driving if it stalls or misfires, since a lean mixture can cause overheating and damage.
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.