What does code P20F3 mean?

Q: What does code P20F3 mean?

SCR NOx Pre-Catalyst Efficiency Below Threshold (Bank 2). P20F3 indicates that the powertrain control module has detected the selective catalytic reduction pre-catalyst on bank 2 is not reducing nitrogen oxides efficiently enough, based on the upstream and downstream nitrogen oxide sensor signals. The computer compares the expected drop in nitrogen oxides across the pre-catalyst to the actual drop and sets the code when the efficiency falls below a calibrated threshold.

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P20F3

P20F3SCR NOx Pre-Catalyst Efficiency Below Threshold (Bank 2)

P20F3 indicates that the powertrain control module has detected the selective catalytic reduction pre-catalyst on bank 2 is not reducing nitrogen oxides efficiently enough, based on the upstream and downstream nitrogen oxide sensor signals. The computer compares the expected drop in nitrogen oxides across the pre-catalyst to the actual drop and sets the code when the efficiency falls below a calibrated threshold.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

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.