Hey I don't own a mustang, I'm just helping out a friend with his.
We got a malfunction in the rear O2 sensors, so I figured I'd start out with replacing
the rear O2 sensor.

The car is a 1998 Mustang V6.

Question is, is P0156 for the driver or passenger side rear O2?
And where should I go to buy a new O2 sensor for cheap?

Is there anything else I should check before putting in a new O2 sensor?

 

Try this link. and you can get O2 sensors from like AutoZone, Kragen, PepBoys..etc..

http://www.troublecodes.net/Ford/eec-vobd2.shtml



Upstream HO2S Circuit Voltage High, Bank No. 2
Passenger side, nearest to the engine

 

all i can say is MAKE SURE its a 02 sensor and that you dont have any vaccume hose leaks because it was gunna cost me a butt-load in 02 sensors when all i need was like a 5 dollar peice from the ford place!

 

That code has nothing to do with vacuum. It indicates a fault in the O2 sensor circuit. And I'll lay odds it is the sensor.

 

I think you accidently read the wrong code, that one is P0155.

P0156 - Downstream HO2S Circuit Fault, Bank No. 2
Is that one the passenger side O2 sensor as well?

 

www.oxygensensors.com , and make sure you get the special socket too for taking them off!!!

 

i know they're a bitch to remove, but are you sure i won't be fine with just a monkey wrench,
or i think i have a set of regular type wrenches 10mm-18mm?

is it a tight fit under there?

but i still need to know... P0156 - Downstream HO2S Circuit Fault, Bank No. 2
is that one the passenger or driver side?

 

OOPS....ok the one furthest away from the engine. Same side tho

 

listen I HIGHLY suggest you go buy or rent the socket from an auto parts store. from that website I gave you the socket is 9.95 , yellow back me up on this!

 

ok i will take your advice and get the socket haha i believe ya
just wondering if my friend really had to spend that $$, guess so.