What does code P2099 mean?

Q: What does code P2099 mean?

Post Catalyst Fuel Trim System Too Rich. P2099 means the engine computer has detected that the post-catalyst fuel trim system is too rich, meaning the oxygen sensor after the catalytic converter is reporting a richer exhaust mixture than the computer expects. The powertrain control module uses the downstream oxygen sensor to fine-tune fuel delivery, and when that correction hits its rich limit, it stores this code.

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P2099

P2099Post Catalyst Fuel Trim System Too Rich

P2099 means the engine computer has detected that the post-catalyst fuel trim system is too rich, meaning the oxygen sensor after the catalytic converter is reporting a richer exhaust mixture than the computer expects. The powertrain control module uses the downstream oxygen sensor to fine-tune fuel delivery, and when that correction hits its rich limit, it stores this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

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