The P2179: System Too Lean Off Idle Bank 2 refers to a condition where the air-fuel mixture in bank 2 is too lean (not enough fuel) when the engine is off idle. This could be caused by air leaks, faulty fuel injectors, fuel delivery issues, or sensor problems.
P2179 – Quick Overview
Code | Information |
---|---|
Meaning | P2179: System Too Lean Off Idle Bank 2 |
Is it serious? | Yes, this can result in poor engine performance, misfires, and potential damage to the engine. |
Possible causes | – Lean condition in bank 2 when off idle – Faulty fuel injectors or fuel delivery issues – Air leaks or sensor problems |
How to diagnose? | – Inspect for air leaks and test fuel delivery system – Check fuel injectors for proper operation – Test and verify sensors for accuracy |
P2179 Meaning
The P2179: System Too Lean Off Idle Bank 2 code indicates that the engine control module (ECM) has detected a lean air-fuel mixture in bank 2 (not enough fuel compared to air) when the engine is off idle. This condition may lead to poor engine performance, rough idling, or even damage to internal components. Common causes include air intake leaks, malfunctioning sensors (such as the mass air flow (MAF) sensor), or issues with the fuel injectors.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for additional related codes that may provide more insight into the issue. | OBD-II Scanner |
Inspect for Air Leaks | Inspect the air intake system, including hoses, intake manifold, and vacuum lines, for leaks that could introduce unmetered air into the engine, leading to a lean condition. | Flashlight, Smoke Tester |
Test Fuel Delivery System | Inspect the fuel delivery system, including the fuel pump, fuel pressure regulator, and fuel injectors, to ensure proper fuel pressure and flow to bank 2. | Fuel Pressure Gauge, Multimeter |
Check Fuel Injectors | Use a diagnostic tool to test the fuel injectors in bank 2 for proper operation. Verify that they are delivering the correct amount of fuel and are not clogged. | Diagnostic Tool, Multimeter |
Test MAF or MAP Sensors | Inspect and test the mass air flow (MAF) sensor and manifold absolute pressure (MAP) sensor to ensure they are providing accurate data to the ECM. | Multimeter, Diagnostic Tool |
Check Oxygen Sensors | Test the oxygen (O2) sensors on bank 2 to ensure they are accurately reporting air-fuel ratios. Faulty sensors could lead to incorrect fuel adjustments by the ECM. | Multimeter, Diagnostic Tool |
Repair or Replace Faulty Components | If any faulty components, such as air intake parts, fuel injectors, or sensors, are found, repair or replace them as needed to resolve the lean condition. | Replacement Parts, Tools |
Clear the Code and Test Drive | After repairs, clear the P2179 code using an OBD-II scanner and take the vehicle for a test drive to ensure the issue is resolved. | OBD-II Scanner |
Recheck for Codes | After the test drive, re-scan the vehicle to confirm that the P2179 code does not return. | OBD-II Scanner |

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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)