My 2004 W211 "check engine" light came on recently and i diagnosed the fault with an OBD code reader and obtained the following 2 results on the reader's screen.

1. PO158
O2 circuit High Voltage (Bank 2, Sensor 2) and the "freeze Frame" stored data as follows;
P0456
Freeze Frame Data
Fuel Sys 1 CL
Fuel SYS 2 CL
Calc Load (%) 25.49
ECT (0C) 85
STFT B1 (%) -1.56

2. P0161
O2 heater Circuit (Bank 2, Sensor 2)

Please i need someone to decode these codes for me so that i can know the faulty parts of the car. Is it something very serious and is it possible for me to get a $ estimate for the repairs?

 

Looks like O2 Sensors are bad. Not too hard to replace, looks like the ones after the cat. converter