Powertrain, generic (extended)

P2179 System Too Lean Off Idle (Bank 2)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Low fuel pressure or air mass sensor fault, usually with P2177 too
Restricted injector on bank 2
Intake leak or front oxygen sensor fault on bank 2

Symptoms

  • Check engine lamp on after two trips
  • Hesitation under load

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–800
Time0.5–3.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injectorintake manifoldoxygen sensor upstreammass air flow sensorfuel pump

Related codes

P2177P2180P2189P0174

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.