tatatana

Hello,
I have a working 2001 Audi A4 quattro AWD 1.8 with the engine light on and with a mileage of 115kmiles.
I scanned the car twice, first time :
P1114 Bank 1 Sensor 2, Resistant Too High
p1118 Oxygen Sensor Heater Circuit, Open Bank 1 Sensor 2
p0140 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
p0431 Warm Up Catalyst Efficiency Below Threshold (Bank 2 Sensor 2)

Read more at: http://www.obd-codes.com/p0431
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p0134 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

Then I reset the car and drive it for one day :
p1114 Bank 1 Sensor 2, Resistant Too High
p1118 Oxygen Sensor Heater Circuit, Open Bank 1 Sensor 2
p1400 EGR ValveCirc Electrical Malfunction

I would like to know what should I do?replace all O2 sensors, only the downstream ones or?
And what could happen if I do nothing?
What is the most important the O2 sensors or the EGR problem?

tatatana

Sorry, I double posted the thread.
Could an admin delete one of the two?