P2189 on Audi
System Too Lean at Idle (Bank 2)
P2189 on Audi vehicles indicates system too lean at idle (bank 2). Au7o has documented this code across 1 Audi model — most commonly on S5. P2189 means the engine computer detected that the air-fuel mixture on bank 2 is running too lean (too much air relative to fuel) specifically at idle. The computer watches the oxygen sensors and has been adding extra fuel (high fuel trim) to compensate, but the correction has reached its limit, indicating an unmetered air leak or a fuel-delivery shortfall. A lean condition at idle commonly causes rough idle, stalling, hesitation, or a surging engine. The usual culprits are vacuum/intake leaks downstream of the airflow sensor or anything restricting fuel. Typical repair costs on Audi range from $600 to $1,200, depending on the specific model and root cause.
Common Causes of P2189
- •Vacuum or intake manifold air leak (gaskets, hoses, PCV)
- •Dirty or faulty mass airflow (MAF) sensor
- •Clogged or weak fuel injectors on bank 2
- •Low fuel pressure (failing pump, restricted filter, weak regulator)
- •Leaking intake gasket or cracked intake boot
- •Faulty or contaminated oxygen sensor giving false lean signal
- •Exhaust leak ahead of the upstream O2 sensor
P2189 on Audi by Model
Audi S5(1 issue)
- PCV Valve (Crankcase Vent Valve) Failure (3.0T)2010-2017
The Audi S5 (2010-2017) with the 3.0T supercharged V6 has a chronic PCV valve (also called air-oil separator or crankcase vent valve) failure. The PCV valve diaphragm degrades over time, causing oil leaks, check engine lights, rough idle, and a loud squealing/whistling noise from the engine. The 3.0T PCV is located at the rear of the engine near the firewall, making it moderately difficult to access. Many B8/B8.5 S5 owners replace the PCV valve and water pump simultaneously to save on future labor costs, since both are common failure items. Audizine, ShopDAP, and Motor Werke report PCV failure as a near-certainty before 100,000 miles. The repair is moderate in cost but ignoring it leads to vacuum leaks and accelerated oil consumption.
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View P2189 across all makes →Frequently Asked Questions
What does P2189 mean on Audi?▼
P2189 stands for "System Too Lean at Idle (Bank 2)." P2189 means the engine computer detected that the air-fuel mixture on bank 2 is running too lean (too much air relative to fuel) specifically at idle. The computer watches the oxygen sensors and has been adding extra fuel (high fuel trim) to compensate, but the correction has reached its limit, indicating an unmetered air leak or a fuel-delivery shortfall. A lean condition at idle commonly causes rough idle, stalling, hesitation, or a surging engine. The usual culprits are vacuum/intake leaks downstream of the airflow sensor or anything restricting fuel. On Audi specifically, this code is documented across 1 model.
What causes P2189 on Audi vehicles?▼
Common causes on Audi: Vacuum or intake manifold air leak (gaskets, hoses, PCV), Dirty or faulty mass airflow (MAF) sensor, Clogged or weak fuel injectors on bank 2, Low fuel pressure (failing pump, restricted filter, weak regulator), Leaking intake gasket or cracked intake boot. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2189 on a Audi?▼
Repair costs on Audi range from $600 to $1,200, depending on the specific model and root cause.
Which Audi models have P2189 documented?▼
Au7o has documented P2189 on 1 Audi model: S5.