P2179 code meaning
System Too Lean Off Idle (Bank 2)
Powertrain system Generic code P21xx codes Check engine light
What P2179 means
P2179 is the bank 2 version of P2177 on engines with a front oxygen sensor for each cylinder bank: the load-dependent, multiplicative share of bank 2's long-term correction has reached its lean limit. GM's 2005 2.8 and 3.6 V6 and the 2008 3.6 LLT use a factor above 1.23, GM's 2024 tables above 1.27, both over two trips. VW's 2014 Touareg sets it for the 3.0 TSI hybrid and the 3.6 VR6 when bank 2 adaptation exceeds +30 %. If both banks are lean at load, look at what they share: fuel pressure, the pump, the air mass sensor. If bank 2 alone is affected, the cause lies on that side, such as a restricted injector, an intake leak at that bank's manifold or a front sensor reading lean. No bulletin naming this code was found.
P2179 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P2179
- Check engine lamp on after two trips
- Hesitation under load
Common causes of P2179
- PossibleLow fuel pressure or air mass sensor fault, usually with P2177 too
- PossibleRestricted injector on bank 2
- PossibleIntake leak or front oxygen sensor fault on bank 2
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel injectorIntake manifoldOxygen sensor upstreamMass air flow sensorFuel pump
What each part of P2179 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 1 | Area: fuel and air metering. |
| 79 | The exact fault in that area. |
What to do next
- Note P2179 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2179
What does P2179 mean?
P2179 means "System Too Lean Off Idle (Bank 2)". P2179 is the bank 2 version of P2177 on engines with a front oxygen sensor for each cylinder bank: the load-dependent, multiplicative share of bank 2's long-term correction has reached its lean limit. It is a generic code, so it means the same on every make.
Is it safe to drive with P2179?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2179 fail an emissions test?
Yes, it can. P2179 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2179 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2179 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.