P2187 on Buick
System Too Lean at Idle (Bank 1)
P2187 on Buick vehicles indicates system too lean at idle (bank 1). Au7o has documented this code across 1 Buick model — most commonly on Enclave. This code means the engine's computer has detected the air-fuel mixture on Bank 1 is too lean specifically at idle, while it stays acceptable at higher speeds. The computer monitors the oxygen sensors and has had to add significant fuel correction at idle to compensate. Because the fault appears mainly at idle, it usually points to a small vacuum or air leak that has a big effect when airflow is low. Symptoms often include rough or unstable idle, stalling, and hesitation when first taking off.
Common Causes of P2187
- •Small vacuum leak (hose, gasket, or fitting)
- •Intake manifold or throttle body gasket leak
- •Faulty or leaking PCV valve/hose
- •Dirty or failing mass airflow (MAF) sensor
- •Leaking or dirty fuel injectors
- •Faulty upstream oxygen sensor
- •Low fuel pressure at idle
- •Leaking brake booster or its vacuum hose
P2187 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 P2187 across all makes →Frequently Asked Questions
What does P2187 mean on Buick?▼
P2187 stands for "System Too Lean at Idle (Bank 1)." This code means the engine's computer has detected the air-fuel mixture on Bank 1 is too lean specifically at idle, while it stays acceptable at higher speeds. The computer monitors the oxygen sensors and has had to add significant fuel correction at idle to compensate. Because the fault appears mainly at idle, it usually points to a small vacuum or air leak that has a big effect when airflow is low. Symptoms often include rough or unstable idle, stalling, and hesitation when first taking off. On Buick specifically, this code is documented across 1 model.
What causes P2187 on Buick vehicles?▼
Common causes on Buick: Small vacuum leak (hose, gasket, or fitting), Intake manifold or throttle body gasket leak, Faulty or leaking PCV valve/hose, Dirty or failing mass airflow (MAF) sensor, Leaking or dirty fuel injectors. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2187 on a Buick?▼
Repair costs vary widely depending on the root cause and specific Buick model.
Which Buick models have P2187 documented?▼
Au7o has documented P2187 on 1 Buick model: Enclave.