O2 Sensor Question
 

Not many people I know would have a smile on their face after getting $3,000 worth of maintenance done to their x5. But yesterday I paid the bill and got to drive her for the first time since 1/10/15!!! Huge smile on my face. Pull out of the parking lot and the F'in check engine light comes on (in true race truck fashion). Two codes:

p0030 - Heater control circuit (bank 1, sensor 1)
p0134 - o2 sensor circuit no activity detected (bank 1, sensor 1)

So I'm guessing I need a new o2 sensor and I may as well do both of the precats right away (sitting at 97K).

Now my questions are:

Does anyone have a good DIY? Haven't gotten a chance to pick up a Bentley Manual yet.

Bank 1 refers to the right side of the engine, correct? Now is that the right side when I'm looking at the engine (aka drivers side) or right side when im sitting in the car (pass side). I had the motor mounts replaced so I'm wondering if something is pinched or didn't get reconnected? I get p0030 on every start up after clearing the code. P0134 seems more intermittent.
P0134 - 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

Read more at: OBD-II Trouble Code: P0134 Oxygen 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)
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P0134 - 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

Read more at: OBD-II Trouble Code: P0134 Oxygen 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)
Copyright © OBD-Codes.com

Guess I could have googled more. Can someone just confirm that this is correct?

8-cylinder, V8 (US models):
M60, M62, S62 – Twin cam (two cams for each bank), 4 valves per cylinder, produced from 1993 through mid-2000s (US)
N62, N63, S65 – Twin cam (two cams for each bank), 4 valves per cylinder, produced from early 2000s to current
Cylinder numbering is 1 through 4 on passenger (right) side and 5 through 8 on driver (left) side. numbers 1 and 5 are at the front, 4 and 8 are at the rear.
Ignition firing order is 1-5-4-8-6-3-7-2 (except S65 = 1-5-4-8-7-2-6-3).
Bank-1 is the passenger side (cylinders 1 through 4), bank-2 is the driver side (cylinders 5 through 8).


So in my scenario, I would be replacing the passengers side pre cat o2 sensor? Is that correct?

Yes, the passenger side though sometimes errors for pre cat O2 sensors

The pre cat 02 sensors are part of the air/fuel mixture calibration. Errors indicating a problem with a sensor can be a malfunction upstream from the sensor. That said, it is recommended the pre cat sensors be replaced at around 60,000 miles. I agree that if you replace one you should do the other at the same time.

There is a socket especially for removing sensors. It can be done without it but it is far easier with the socket. All you need to do is disconnect the wires at the connector and screw the old one out.

That's what I'd look for first. Or even just a connector that is not fully plugged in. Odd for it to show up suddenly after all that work. Bad for the mechanic to deliver it to you like that.

I recently replaced the pre-cat O2 sensors in my 2001 3.0, where they were working fine but at 169k miles. I thought I might see an increase in MPG following the change, but it runs just like before, which is very well. So the O2 sensors can go for a long time.

If I had just spent $3k on repairs, my first step would actually be to ask the mechanic about it and if he will inspect and fix for free if indeed he tweaked it.

I did go back today and asked if he had touched the O2 sensor in any way and he said no. I would trust the shop that I go to with any car (I know the mechanics on a personal level). It sucks but ultimately the sensors both have 97k on them so they should be replaced anyway.

Does the skid plate need to be dropped for replacement of the precat O2 sensors. When I did a coolant flush I rememeber seeing the pre cat o2's (dropped the skid plate) but I can't remember if I would have access with the plate on or not. I'm sure I'll see it once I get it on the lift

I don't know on this one since mine is a 3.0. On my car, the sensors are easily accessible, right next to the spark plugs, accessible from the top = very easy.

If you believe there is a good chance that the sensors are actually OK and something in the connector or wiring or ... is the real problem, and if you can easily do this yourself, you may want to swap the two pre-cat sensors as a test to see if the codes stay where they are or follow the bank 1 sensor. Because you may end up finding the codes unchanged after swapping in new sensors. This test would confirm that the sensor itself is bad before you buy new parts, etc.

From everything I've read, you get to the ones on the v8 from the bottom. If the 3.0 in the x5 is set up the same way as the 3.0 that I had in my 330 I know exactly what you are referring to.

I have a feeling the sensor is bad. I recently bought an Ultra Gauge so I could have more output then just what the gauges show. When I look at bank 1, sensor 1, the it shows no movement. Because it is precat the values should be changing. bank 2 sensor 1 does show fluctuation while b1s1 sits steady and does not move. I have a feeling the sensor is just shot (unlike my thought that it wasnt even plugged in before). I already bought the parts to fix it. Might as well at 97k.

If you have a scanner that can provide live data, you can see if the sensor is working before going through all the trouble of replacing a good part and shelling out good money. Torque app has live data as part of it features. You can see what type of voltages the 02 sensors are producing.

Exactly what I did with the Ultra Gauge (btw great investment at $90 shipped). Bank 1 sensor 1 shows voltage but it is not fluctuating. I'm not an expert when it comes to this but that would tell me it is plugged in getting power but not reading how it should (pre cat should have fluctuating values where as the post cat should remain constant if the cats are operating correctly)