What Does P2189 Mean?
The PCM is adding excessive fuel (positive long-term fuel trim) at idle to compensate for a lean condition on Bank 2. The air/fuel mixture contains too much air or insufficient fuel at idle speeds only on the Bank 2 cylinder bank.
Common Causes
40%
Vacuum leak specific to Bank 2 intake runners or gaskets
25%
Clogged or restricted fuel injectors on Bank 2 cylinders
15%
Low fuel pressure or weak fuel pump affecting Bank 2
15%
Exhaust leak before Bank 2 oxygen sensor
5%
Failed Bank 2 oxygen sensor providing false rich reading
Diagnostic Steps
1
Step 1: Compare Bank 1 and Bank 2 fuel trim values at idle; Bank 2 should show significantly higher positive LTFT if lean
2
Step 2: Perform smoke test or propane enrichment focused on Bank 2 intake manifold area and vacuum connections
3
Step 3: Check for exhaust leaks specific to Bank 2 (passenger side on most engines) before upstream O2 sensor
4
Step 4: Test fuel injector resistance and flow balance for Bank 2 cylinders; clean or replace as needed
5
Step 5: Verify fuel pressure meets specification; monitor Bank 2 O2 sensor response to rule out sensor malfunction
Estimated Repair Cost
$100 - $850
Parts + labor, varies by vehicle and location
The PCM is adding excessive fuel (positive long-term fuel trim) at idle to compensate for a lean condition on Bank 2. The air/fuel mixture contains too much air or insufficient fuel at idle speeds only on the Bank 2 cylinder bank.
The most common cause of P2189 (System Too Lean at Idle Bank 2) is: Vacuum leak specific to Bank 2 intake runners or gaskets
Typical repair costs for P2189 range from $100 to $850, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive but may experience rough idle, misfires on Bank 2 cylinders, or hesitation. Prolonged lean operation can damage catalytic converter and cause Bank 2 cylinders to overheat.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2189 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
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