Today the engine check light came on in my S4 that I bought 2 days ago The code was p1131 which I believe is O2 sensor on driver side. I was wondering what I need to do: Do I replace it or can I fix it or where can I get one and how hard is it to replace?

Things wrong with recently purchased 2001 S4 2.7L twin turbo 6sp manual 85,500 miles with APR Short Shifter, APR SRT Full exhaust, APR Chip, H&R full coil overs, OEM RS4 one piece headlights, 19" RS4 Reps, DVD/Navi in dash, 3M clear car bra:

Sunroof wont open half the time
O2 sensor check
Whining of transmission in reverse
Screeching of brakes but brake pads are good

Easy fixes or big troubles? Whats going to be the first major thing I will need replaced?

 

I just discovered that the previous owner of my car had blacked out three warning lights on my dash . . . because they were on! That's another story all together though. Anyway, I pulled the codes on mine cuz the ABS + Brake lights are on and the CEL is on too. I have a bad o2 sensor, bank 2 sensor 1, and a bad ABS control module. Based on your description of brake performance, I wonder if yours is gonna act up too! Its an expensive little module, but if your car has bosch 5.3 you can have it rebuilt by modulemaster.com for about $160 plus shipping vs. $800 plus for the part from a dealer. Well enough about that, yours isn't even broken yet.

The drivers side upstream O2 sensor is a PITA to replace, but manageable, passenger side is much easier. You'll have to remove the coolant reservoir first, and then be persistent with plenty of socket extensions and limber fingers. Get a replacement from your local parts store, many of them stock the OEM ones for these cars, they are around $120 to $160 each. good luck man.

 

Sunroof wont open have the time:

Depending on yoru sun roof switch, it can be open and cleaned or it can just be replaced. Junk/salvage yards are your friend. Ebay too.

To avoid this in the mean time. Simply press in on the switch after you turn it. Push as if your trying to get the sunroof to tilt open. This usually gets the bugger to work.


O2 sensor:

Yes you are correct, Drivers side primary oxygen sensor. This is the heater element having failed. There is a guide somewhere to checking it with a multimeter. 2 of the wires to the o2 sensor are heater wires. (the heater is used to achieve operating temperatures of the 02 sensor before the engine is completely warm. This reduces emissions, at the cost of adding complexity)

This sensor is not to hard to replace, Vast sells them in pairs. Or there were some listed for sale the other day right here on audiworld, b5s4 forum.

I believe the transmission always whines in reverse, or ateast a couple of years of it did. Whatever types of gears they used in it. I think its normal.

Brake screaching:

I assume this is the step on the breaks and they squeal real bad at low speeds?

You could try putting some high temperature antisieze on the back of the pads. This is supposed to be done to reduce squeeking/squeeling but alot of places don't always do it.

 

My bad, I read that so fast I assumed you meant that your TIRES were screeching to a stop when you hit the breaks, as if the ABS wasn't working. Thats what mine did . . . which tipped me off to wonder why the ABS light wasn't on. Anyway, yeah, just try changing the pads and lube the back of the pad with the suggested antizieze as recomended

 

O2 sensors are hard to replace??? LOL
dont listen to the wrench-noob
it aint that hard....
oh and you dont need OEM O2 sensors for secondaries. get the universals for 60 bux and take the extra 10 minutes to splice the wires. works fine (esp for secondary o2)

 

Thanks, is there a tutorial on how to do it somewhere?

 

dude youre making it harder than it is before you even attempt it. cut the damn wire pull it out from under the hood and use a 22mm wrench to remove the old sensor from your cat.
feed the new one from under the hood to the underside of the car.

 

I thought that the p01131 code is for sensor #1 bank 2, which is a primary O2 sensor, no? They are a little tougher to replace than the secondaries I've heard, but I could be wrong, I am a bit inexperienced on exhaust stuff though. Just what I thought.

 

It is the primary so your right that is it harder than a rear as it is a tight fight. But it is easier in that you don't have to fish a wire. None of them are hard to do. You can run into little issues like your hand not wanting to fit into the tight places. Renting the O2 sensor tool from autozone helps, as you won't have to spent 20 min grinding away at a standard O2 socket like I did before I knew about free tool rentals.

 

Good call on the tool rental, I'll definately do that when I tackle mine today