A leaking or dripping fuel injector on bank 2 that delivers more fuel than the computer commands; A faulty mass airflow sensor that over-reports airflow, causing the computer to add too much fuel; A stuck-open or leaking evaporative emissions purge valve that allows fuel vapor into the intake when it should not; High fuel pressure from a failing fuel pressure regulator or a restricted fuel return line; A faulty oxygen sensor on bank 2 that reads lean when the mixture is actually correct, tricking the computer into adding fuel; A contaminated or incorrectly calibrated mass airflow sensor hot wire or element; A leaking intake manifold gasket or vacuum line on bank 2 that lets unmetered air in, though this more often causes a lean condition

DTC codes / P21xx · Fuel and air metering / P2180

P2180System Too Rich Off Idle (Bank 2)

Q: What does code P2180 mean?

System Too Rich Off Idle (Bank 2). P2180 means the engine computer has detected an excessively rich air-fuel mixture on bank 2 whenever the engine is running above idle speed, so the powertrain control module has reached the limit of its ability to lean the mixture out. Bank 2 is the side of the engine that does not contain cylinder number one, and the fault is flagged when fuel trims stay too far negative for too long off idle.

P2180 means the engine computer has detected an excessively rich air-fuel mixture on bank 2 whenever the engine is running above idle speed, so the powertrain control module has reached the limit of its ability to lean the mixture out. Bank 2 is the side of the engine that does not contain cylinder number one, and the fault is flagged when fuel trims stay too far negative for too long off idle.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering

Symptoms you may notice

Often no symptoms besides the warning light, especially in the early stages
A noticeable drop in fuel economy compared with normal driving
Black, sooty exhaust smoke or a strong fuel smell from the tailpipe
Rough running, hesitation, or misfiring when accelerating or cruising above idle
The engine may feel sluggish or lack power under load
A failed emissions test with high carbon monoxide or hydrocarbon readings

Common causes, most likely first

A leaking or dripping fuel injector on bank 2 that delivers more fuel than the computer commands
A faulty mass airflow sensor that over-reports airflow, causing the computer to add too much fuel
A stuck-open or leaking evaporative emissions purge valve that allows fuel vapor into the intake when it should not
High fuel pressure from a failing fuel pressure regulator or a restricted fuel return line
A faulty oxygen sensor on bank 2 that reads lean when the mixture is actually correct, tricking the computer into adding fuel
A contaminated or incorrectly calibrated mass airflow sensor hot wire or element
A leaking intake manifold gasket or vacuum line on bank 2 that lets unmetered air in, though this more often causes a lean condition

How to diagnose and fix it

Connect a scan tool and record live data for bank 2 short-term and long-term fuel trims at idle and at 2500 rpm to confirm the rich condition is real and not a sensor artifact
Inspect the bank 2 oxygen sensor signal and compare it with bank 1 to see whether the sensor is skewed or the mixture is genuinely rich
Check fuel pressure with a gauge and compare it with the manufacturer's specification, looking for pressure that stays too high
Perform an injector balance test or pull the bank 2 injectors and inspect for leaking or dripping after shutdown
Clean or replace the mass airflow sensor only after verifying its reported airflow against a known-good value or a scan tool graph
Test the evaporative emissions purge valve for sticking open by commanding it closed with a scan tool and watching fuel trims
After repairs, clear the codes and drive the vehicle through a complete off-idle drive cycle to confirm the fuel trims return to normal and the code does not reset

What a rich bank 2 code really tells you

A negative long-term fuel trim on bank 2 that is much larger than bank 1 points to a problem specific to that bank, such as a leaking injector, rather than a global issue like fuel pressure.
A mass airflow sensor that over-reports airflow will make both banks rich, so if bank 1 trims are also negative, look at the airflow sensor before condemning bank 2 injectors.
A lazy or contaminated oxygen sensor on bank 2 can report a false lean condition, causing the computer to add fuel and set a rich code even when the actual mixture is correct.
A sticking evaporative purge valve is a commonly missed cause because it only affects fuel trims when the valve is commanded open, often at off-idle conditions.
Do not replace the catalytic converter for this code until fuel trims are corrected, because a rich mixture will quickly damage a new converter and the code will return.

Can I keep driving with P2180?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration and long trips because the rich mixture can overheat and damage the catalytic converter and waste fuel. Have the fault diagnosed promptly to prevent more expensive repairs.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.