My 2006 Super V8 Portfolio has a P2099 code. Replaced Mass Airflow Sensor. Code is back after driving 20 kilometers. Took it to the Jag dealer for diagnostics and they identified 2 codes, P0420 and P2099 but they said they were not able to determine cause.
Any suggestions would be greatly appreciated.

 

If DTC P0420 is present, check for misfire(s) on Bank 1 cylinders as the catalyst has been damaged. Did the main dealer indicate what the STFTs and LTFTs are? DTC P2099 may be caused by a vacuum leak, so a smoke test would indicate the source of the leak(s) causing the ECM/PCM to make Bank 2 run rich.

It would be helpful to know the number of kilometres/miles showing on the instrument cluster.