P2179
System Too Lean Off Idle Bank 2
Fuel trims on bank 2 show a lean deviation during off-idle operating conditions. Causes are similar to bank 1 but isolated to the second cylinder bank.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
Common causes
Ordered by how often each turns out to be the cause.
- Vacuum leak on bank 2Common
- Low fuel pressurePossible
Parts involved
- Intake Manifold
- Vacuum Hoses
- Fuel Injector
- Mass Air Flow Sensor
P2179 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.