P2177 on Buick
System Too Lean Off Idle (Bank 1)
P2177 on Buick vehicles indicates system too lean off idle (bank 1). Au7o has documented this code across 1 Buick model — most commonly on Enclave. The PCM detected that bank 1 is running lean (too much air relative to fuel) during off-idle/cruise conditions, with long-term fuel trims maxed out trying to add fuel. A lean condition under load that fuel trim cannot fully correct.
Common Causes of P2177
- •Vacuum or intake air leak
- •Weak fuel pump / restricted fuel filter
- •Dirty or failing MAF sensor
- •Clogged/leaking fuel injectors
- •Exhaust leak ahead of upstream O2 sensor
P2177 on Buick by Model
Buick Enclave(1 issue)
- Cold-Weather PCV Deposits Can Cause Reduced Power (PI0746)2008-2011
GM PI0746 covers 2008-2011 Buick Enclave vehicles with the 3.6L LY7 or LLT engine. After a cold start or low-ambient-temperature driving, condensation can freeze at the throttle-body base while engine vapors, fuel dilution and oil mist collect in the air-inlet duct. The condition can illuminate the MIL and cause poor performance or reduced acceleration.
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View P2177 across all makes →Frequently Asked Questions
What does P2177 mean on Buick?▼
P2177 stands for "System Too Lean Off Idle (Bank 1)." The PCM detected that bank 1 is running lean (too much air relative to fuel) during off-idle/cruise conditions, with long-term fuel trims maxed out trying to add fuel. A lean condition under load that fuel trim cannot fully correct. On Buick specifically, this code is documented across 1 model.
What causes P2177 on Buick vehicles?▼
Common causes on Buick: Vacuum or intake air leak, Weak fuel pump / restricted fuel filter, Dirty or failing MAF sensor, Clogged/leaking fuel injectors, Exhaust leak ahead of upstream O2 sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2177 on a Buick?▼
Repair costs vary widely depending on the root cause and specific Buick model.
Which Buick models have P2177 documented?▼
Au7o has documented P2177 on 1 Buick model: Enclave.