Hi Guys

Posted this on a couple of forums, need some help from the hardcore 2.7T guys who know their stuff!

Tuesday, 06 April 2010, 17:03:30
VAG-COM Version: Release 409.1-S

Control Module Part Number: 4B0 907 551 AA
Component and/or Version: 2.7l V6/5VT G01 0001
Software Coding: 06712
Work Shop Code: WSC 26130
Additional Info: WAUED64B91N047196 AUZ7Z0Y1562177

1 Fault Found:

16534 - Oxygen (Lambda) Sensor B2 S1: Malfunction in Circuit
P0150 - 35-10 - - - Intermittent


I had this problem originally and it would come back immediately... then I had replaced this Oxygen sensor with the Bosch universal 4-wire planar sensor - spliced in (NOT soldered) following the strict tech articles and instructions from Bosch, and the actual Bosch posi-lock connector. It's super secure and I doubt it could be the cause of the issue, but... anybody have experience doing this also on a 2.7T? The code now comes back every 2 or 3 days.

What gives? Is there a known failure or weak point in the harness or connector, and if so how would I test for this?

Also on my readiness test, even after warming the car up it says "failed or incomplete" on "Oxygen sensors" and "Catalytic converter" categories. Is this likely due to B2 S1 malfunction in circuit? I have proper piggie pipes (with relocated rear O2's) if that makes a difference... however the B2 S1 sensor problem precedes this by a couple of months, and being B2 S1 which is front sensor and should have nothing to do with piggies... ?

This issue is driving me CRAZY... Thanks in advance

 

I recently replaced the B2S1 O2 sensor with an original Bosch from Autozone, $160. It was a PITA to get too. Since you already did the hard part of getting an O2 sensor in there, it should be easy to get an oem wired one in there now.

I have done some wiring in the past, and since your code indicates a bad circuit, I think it is probably the spliced wiring connection failing.

Maybe you could pull the original connectors apart on the firewall and shoot it with some dielectric grease from any parts store. Maybe it's just a bad or loose connector.

Good luck.

 

I just remembered that the Bentley has a procedure for testing the wiring from the oem connector on the firewall. It involves checking the resistance on the different wires for a normal range. Out of normal means replace sensor.

Do you have a bentley?

 

Yeah I do - I'm going to look into that. I found a procedure online to test the heater circuit, but that's not my issue I don't think.

I did notice last night looking at it that somehow the connector had fallen out of the firewall hanger bracket thats supposed to hold it in place, so it was bouncing around to some degree. I'm not sure if this would be enough of a change to cause a malfunction, maybe if a pin was loose or something in the connector, in addition to it bouncing around?

I took it apart, cleaned the connectors with some alcohol based electronic circuit cleaner, checked all the pins and let it dry for an hour, then connected it all and hung back into the bracket.

I really hate to replace it with the $200+ CAD OEM B2S1 sensor, especially since I did my B1S1 already the same way with the universal sensor and its working perfectly.

I'll check the Bentley for this test and monitor over the next week or so and hopefully have a result.

Thanks

 

Amazon sells them for cheaper.

 

the universal sensors are fine, they are the same sensors just minus the connector so as long as you wired it right your fine there. You are probably getting a problem from the relocation of the sensors. If its even just a little off I can see it effecting the signal every once and awhile. Maybe try some 02 sensor dfouls

 

I don't think the piggie pipes / relocation have anything to do with it, because I'm talking about B2S1 which is the first o2 in the top of the DP before anything else, and nothing has changed there since day 1.

Do you know this for a fact? I've found lots of opinions on it... some say they are the same, now I'm reading others say they are not and they won't function like OEM, so I'm not sure what to think. I know I have them spliced up correctly, and the Bosch connector feels very solid... but then why the intermittent codes.

Does anyone know if there is any difference whatsoever in the readings between universal sensor and a OEM ?

 

After clearing codes, I monitored the readings on my code reader and they are showing fluctuating between roughly 0.2ish and 0.9 volts, idle, revving the motor, etc.

Does this sound like "normal" voltage?

If it is, that should mean the O2's are fine, and doing their job, right??

 

The o2 sensor is a simple piece of electronic equipment that has been around for decades. As long as you have the right 02s and they are installed correctly they should be fine. If you are getting codes you have something else up. Consider that maybe your sensors are fine and they are showing something else wrong. Maybe they are giving the wrong signals because you are having occasional misfires or rich mixtures in the cylinder.

 

Yes.. they are the same. You should pull that crappy non-solder splice and solder them up.. resistance thats not suppose to be there will screw it up and set a code.