OBD2 Car ScannerWhat does P2179 mean?
P2179 stands for System Too Lean Off Idle Bank 2. The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Powertrain codes cover the engine, transmission and emissions. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Vacuum or intake air leaks
- Dirty or faulty mass airflow (MAF) sensor
- Faulty oxygen sensor or its wiring
- Fuel pressure problems (pump, filter or regulator)
- Clogged or leaking fuel injectors
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does P2179 mean?
P2179 means “System Too Lean Off Idle Bank 2”. It belongs to the fuel and air metering group: The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Is it safe to drive with P2179?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear P2179?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- P2175Throttle Actuator Control System - Low Air Flow Detected
- P2176Throttle Actuator Control System - Idle Position Not Learned
- P2177System Too Lean Off Idle Bank 1
- P2178System Too Rich Off Idle Bank 1
- P217AFuel Injector Group G Supply Voltage Circuit/Open
- P217BFuel Injector Group G Supply Voltage Circuit Low
- P217CFuel Injector Group G Supply Voltage Circuit High
- P217DFuel Injector Group H Supply Voltage Circuit/Open
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.