O2 sensor

[moose]

I went to my local VW dealership when I had my CEL come on.; Well to my suprise I didn't have to pay for the computer check, but they did discover that my O2 sensor is failing or has failed. I was wondering how hard it was to replace and how much they usually cost?

[Porkchop]

Did they base the diagnosis on a code or did they actually have a way to test the actual O2 sensor?

There are two sensor, both are easy to replace if you have a jack & jackstands or ramps. One is on the downpipe on the backside of the engine but must be accessed from underneath.

The 2nd is just past the catlytic convertor.

If they diagnosed based on a code, let us know what the code is because it should also indicate which sensor is the problem (Bank 1 or Bank 2).

However, I had an O2 code and turns out it was a bad MAF... thankfully I only paid $22 for the O2 sensor and changed it myself. It was relatively inexpensive misdiagnosis on my part. However, when you're paying someone else to do the work, it can get expensive while they guess what is actually wrong.

[moose]

the codes are as follows po411, po134 po 1128, and po o135.

[ilpotosino]

CEL came on in my NB 2003 2.0 the read code was
16518- P0134
O2 Sensor Circ.,Bank1-Sensor1 No Activity Detected
I did change the sesor and it was OK for a few days... and CEL came on again!
same fault code

[SAMPO]

I had similar issues with that specific cel, Bank1 is usually idicative with the 1st 02 sensor, I was able to find a generic sensor of e-bay express for 22$ shipped, and I've had no problems since. Hope it helps.

[02LexBeetle]

Bank1 is usually idicative with the 1st 02 sensor

Guys, I'm fairly certain that Bank 1 does not indicate sensor 1. Although his codes do indicate which sensor's are affected.

Remember that these codes are generic and used on all cars since Jan. 1, 1996. So they have to have representations for 3 cylinders, 4, 6, 8, 10.. etc. My understanding is that Bank 1 represents the side of the exhaust that contains cylinder 1. Bank 2 would represent the side of the motor that does not have cylinder 1. Since our cars have an inline 4, I would think that the Bank 1 code is the only one we would get since there isn't a bank 2 (or a exhaust side that doesn't contain cylinder 1).

P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0411 Secondary Air Injection System Incorrect Flow Detected
P1128 Long Term Fuel Trim B1 System Too Lean

Although you asked about 02 sensors, I thought I would throw in my thoughts on your other codes anyway.

The last code, P1128, is telling you that your car is running too lean. This, in my opinion, is your car getting in unmetered air. The could many reasons for this. Checking for vacuum leaks would be a good place to start. A bad MAF could be letting in unmetered air as well. But P0411 and P1128 both would have me under the hood looking for vacuum leaks.

I hope that helps.

[ilpotosino]

ty so much

[SAMPO]

16514- P0130
O2 Sensor Circ.,Bank1-Sensor1 Malfunction

This is the code that my car was throwing, its seems pretty clear to me. I understand that not all cars are created equal and I am sure that different scanners may have variations of codes. As far a my car was concerned it seemed pretty self explanitory. I apologize to all concerned if I didn't make my self clear with the remainder of the code that came up in my car.

[Genesis]

I've been experiencing the same problem lately. I had the codes read at Advanced Auto Parts and it said "Bank 1 O2 Sensor had low threshold." The info you guys have provide in this thread has been very helpful.