P2099Fuel & Air Metering

Post Catalyst Fuel Trim System Too Rich Bank 2

P2099 is the Bank 2 version of the post-catalyst too rich fault. The downstream O2 sensor on Bank 2 reports a persistently rich exhaust. Common causes are a rich running condition, a leaking injector, high fuel pressure, or a failed rear O2 sensor.

🚗 Yes, short-term, but a rich condition wastes fuel and can foul the catalytic converter.

MEDIUM

severity

🎯 Top Causes, Ranked by Likelihood

#1Actual rich condition (leaking injector, high fuel pressure)$60-$600

40%

Extra fuel shows up as a rich post-cat signal on Bank 2.

#2Failing downstream O2 sensor$60-$300

25%

A contaminated post-cat sensor reports false rich readings.

#3Leaking fuel pressure regulator$60-$300

20%

A leaking regulator raises fuel delivery.

#4Restricted air intake or dirty MAF$20-$300

15%

Reduced airflow or a skewed MAF can drive the mixture rich.

🩺 Common Symptoms

Check engine light on
Reduced fuel economy
Possible black smoke or fuel smell
May fail an emissions test

💰 Repair Cost: DIY vs Shop

DIY Cost

$50-$400

Shop Cost

$150-$700

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P2099

1Scan for related rich codes such as P0175

2Check fuel pressure and inspect for leaking injectors

3Review upstream and downstream O2 live data on Bank 2

4Inspect the air intake and MAF sensor

❓ Frequently Asked Questions

Can I drive with a P2099 code?

Short-term yes, but a rich condition wastes fuel and can foul the catalytic converter. Repair it soon.

How much does it cost to fix P2099?

Depending on the cause, expect $150 to $700 at a shop, or less for a DIY sensor or minor part.

What is the most common cause of P2099?

An actual rich running condition, such as a leaking injector or high fuel pressure, is the most common cause on Bank 2.

🔗 Related Codes

P2096P2097P2098P0175P0430