System Too Rich Off Idle Bank 2
The Powertrain Control Module (PCM) has detected that the air-fuel mixture is excessively rich (too much fuel or too little air) on Bank 2 while the engine is operating above idle speed. This code is set when the short-term and long-term fuel trims exceed their negative limits to compensate for the rich condition during off-idle driving.
While the vehicle can usually still be driven, a persistent rich condition can eventually damage the catalytic converter and foul spark plugs. It should be diagnosed and repaired soon to prevent more expensive emissions system failures.
Common symptoms
- Illuminated Check Engine Light
- Decreased fuel economy
- Strong smell of unburned fuel from the exhaust
- Black smoke emitting from the tailpipe
- Engine hesitation or rough running under load
Likely causes
- Leaking or stuck open fuel injector on Bank 2
- Faulty or contaminated Mass Airflow (MAF) sensor
- Defective Bank 2 upstream oxygen (O2) or air/fuel ratio sensor
- Excessive fuel system pressure (faulty regulator)
- Restricted engine air intake or clogged air filter
What to check before replacing parts
Check the engine air filter and intake system.
Look for: Look for a severely clogged air filter or blockages in the intake tract that could restrict airflow and cause a rich condition.
Monitor live fuel trim data using a scan tool.
Look for: Observe the short-term and long-term fuel trims for Bank 2 off-idle; consistent negative values (e.g., below -15%) confirm the PCM is actively pulling fuel to correct a rich condition.
Inspect and test the Mass Airflow (MAF) sensor.
Look for: Check for contamination on the sensor wire and verify that the MAF g/s reading scales smoothly and appropriately with engine RPM.
Test the fuel system pressure.
Look for: Connect a mechanical fuel pressure gauge and verify the pressure is within the manufacturer's specified range; excessively high pressure indicates a failing fuel pressure regulator.
Evaluate Bank 2 fuel injectors for leakage.
Look for: Perform an injector balance test or check for rapid fuel pressure drop-off after engine shutdown, which indicates a leaking injector on that bank.
This page explains the generic P2180 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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