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.

Likely causes

Symptoms

• Malfunction indicator lamp on
• Usually no noticeable change in driveability

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: fordservicecontent.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.