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P2099 Fault Code


You can find information about the P2099 fault code on this page.

We have given it a seriousness of 3/10 with 1 being the least serious and 10 being the worst.

P2099 Short Description

"Post Catalyst Fuel Trim System Too Rich Bank 2"

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Description Icon Long Description

Fault code P2099 is logged when the powertrain control module (PCM) has detected an issue that the exhaust gases are excessively rich.

This occurs when the PCM has determined that the signal from the oxygen sensor downstream of the catalytic converter indicates that the exhaust gases have too much unburnt fuel in the mixture.

The heated oxygen sensors send information to the PCM, which in turn allows it to regulate and optimize the air-fuel ratio in the combustion chambers to increase performance and reduce emissions.

Engines run on an ideal fuel ratio of 14.7 parts of air to every 1 part of fuel. The term rich is used to describe an engine that is running with too much fuel in the air-fuel mixture. This can have several implications for the engine.

Some of the most commonly reported P2099 codes come from manufacturers like Jeep, Ford, and Mercedes-Benz.

Warnings Icon Other Signs of This Problem

There are several common indicators that will be noticed whenever a vehicle is running rich. There are also some signs that are more closely related to code P2099 as well. The most obvious is that the Check Engine light may be on.

In the case of the engine running rich, it is possible the vehicle will display reduced performance in various ways.

These can be things like rough idling, poor acceleration, and worse fuel economy.

Additionally, the catalytic converter can show off signs of the issue. It is possible for it to become extremely hot due to the error.

Similar fault codes to this issue include P0030, P0032, and P0058.

Broken Down Icon What Could Be The Problem?

There are various factors that can potentially cause an engine to run excessively rich. These can typically relate to either the fuel injection system or the air intake.

A vacuum or air intake leak can easily be the cause of any rich fault code.

Fuel injection issues can also be the cause. Clogged or faulty fuel lines, injectors, and filters can all throw off the ideal air-fuel mixture.

Additionally, a fault mass airflow (MAF) sensor can result in the PCM supplying the wrong ratios of air and fuel. An issue with the MAF can result in codes like P0101 up to P0104.

Another possible cause is a faulty oxygen sensor. This can be that the sensor itself is not working or the wiring or connections are damaged.

Fixed Icon Fixes

There are several fixes for the various problems that can cause P2099.

If there are any vacuum or line leaks, these must be repaired accordingly.

Any issues with the fuel system must also be rectified. A faulty fuel injector, clogged filter, or a faulty pressure regulator all need to be replaced if they are not supplying the desired amount of fuel.

Similarly, a faulty MAF sensor must be replaced. Cleaning the MAF sensor can also solve the issue.

A faulty catalytic converter should also be replaced. However, due to the cost, it is important to ensure that the converter is really at fault.

Danger Icon Seriousness

Fault code P2099 should be considered moderate in terms of seriousness. It does not pose an immediate risk to various components, but this can change over time.

It is recommended to have this fault code fixed as soon as possible, ideally within a few days.

P2099 Image

Commonly Affects

Error Icon P0010

Intake Camshaft Position Actuator Circuit / Open (Bank 1)

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Error Icon P0011

Intake Camshaft Position Timing - Over-Advanced (Bank 1)

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Error Icon P0012

Intake Camshaft Position Timing - Over-Retarded (Bank 1)

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Error Icon P0013

Exhaust Camshaft Position Actuator Circuit / Open (Bank 1)

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Error Icon P0014

Exhaust Camshaft Position Timing - Over-Advanced (Bank 1)

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Error Icon P0016

Crankshaft Position Camshaft Position Correlation Bank 1 Sensor A

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