P2098: Post Catalyst Fuel Trim System Too Lean (Bank 2)

P2098 is the bank 2 version of P2096 on V and flat engines with a catalyst and rear oxygen sensor per bank. The post-catalyst trim of bank 2 has reached its lean-side limit because the rear sensor of that bank keeps reporting rich exhaust. Ford monitors both banks the same way and sets the code 5 s after the bank 2 rear bias trim reaches -0.083; GM's Bosch-based 2005 2.8 and 3.6 V6 and the 2008 3.6 LLT list it as a rich shift of the secondary trim beyond its calibrated limit. If only one bank reports it, compare the two banks' rear sensor signals and the front sensor readings: a fault on one side points to that bank's sensors or its exhaust, whereas both banks together hint at a common cause such as fuel or calibration. Audi saw P2098 with P2096 on 2013 to 2016 A8, S6, S7, S8, RS 6 and RS 7 4.0 TFSI, caused by contaminated reference air ducts in the rear sensors, not by the front sensors the guided test suggests.

Medium severity. Can I keep driving?You can usually keep driving, unless you notice a loss of power, which may point to a blockage. The car may not pass an emissions inspection.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

Malfunction indicator lamp on
Usually no noticeable change in driveability

Most likely causes

Bank 2 rear oxygen sensor skewed rich
Bank 2 front sensor reading lean

What to check, in order

Start with the simplest. You can tick off each step.

First resolve any misfire or fuel mixture codes
Look for exhaust leaks between the engine and the second sensor
Use live data to compare the signals from both oxygen sensors
Check for a blockage by measuring exhaust back pressure
Replace the catalytic converter only at the end of the diagnosis

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2098 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
0: Subsystem depends on the code range
98: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2098?

You can usually keep driving, unless you notice a loss of power, which may point to a blockage. The car may not pass an emissions inspection.

What causes code P2098?

The most common causes are: bank 2 rear oxygen sensor skewed rich; bank 2 front sensor reading lean.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.