How much does it cost to fix P2179?

DIY repair typically costs $10–$150 for parts. Professional repair runs $100–$500 including parts and labor.

P2179

Powertrain

Moderate

System Too Lean Off Idle - Bank 2

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Code P2179 is the Bank 2 companion to P2177 — it indicates the engine is running too lean on Bank 2 during off-idle operating conditions. On V-type and flat engines, Bank 2 is typically the side that does not contain cylinder #1. The 'off-idle' designation means the lean condition occurs specifically during acceleration, cruising, or higher RPM operation rather than at idle.

Since this code is specific to Bank 2, the problem is likely isolated to components that serve that particular cylinder bank. The most common cause is a vacuum leak on the Bank 2 side of the intake manifold. This could be a cracked hose, a leaking gasket, or a faulty PCV valve or line on that side of the engine. The bank-specific nature of the code helps narrow down where to look.

Diagnosis should focus on the Bank 2 side of the engine. Use a smoke test to check for vacuum leaks in the intake plumbing, and inspect the intake manifold gasket for that bank. Also check the exhaust system for leaks before the Bank 2 upstream O2 sensor, as an exhaust leak can make the sensor falsely report lean. If both P2177 and P2179 are present simultaneously, the problem is likely something common to both banks, such as the MAF sensor or fuel pump.

Severity

Moderate — Address SoonThis Week

Symptoms

•Hesitation or stumbling during acceleration
•Engine runs rough above idle RPM
•Reduced power and fuel economy
•Check Engine Light on
•Misfires or surging at cruising speeds

Likely Causes

Vacuum leak on Bank 2 side of the intake35%

A cracked vacuum hose, leaking intake manifold gasket, or broken PCV line on the Bank 2 side allows unmetered air to enter those cylinders specifically, creating a lean condition that only affects Bank 2.

Weak fuel delivery to Bank 2 injectors25%

Partially clogged fuel injectors on Bank 2, or a fuel rail pressure issue affecting that bank, can cause insufficient fuel delivery during higher-demand off-idle conditions.

Faulty mass airflow sensor20%

A contaminated MAF sensor underreporting airflow affects the entire fuel calculation, but if Bank 2 has slightly tighter tolerances or other marginal issues, it may trigger lean on Bank 2 before Bank 1.

Exhaust leak before the Bank 2 O2 sensor20%

An exhaust leak near the Bank 2 upstream oxygen sensor allows ambient air to reach the sensor, causing it to report lean and the PCM to detect a lean condition on that bank.