2003 S6 - Oxygen Sensor Issues (2003 S6)

[Uwe]

WTF is a Firewall in a car ??

It can refer to two things.

1) Universally, it's the metal between the cabin and the engine bay which keeps engine fires out of the cabin long enough for the occupants to depart the vehicle. Checking Wikipedia, I believe you Brits more commonly call it the "bulkhead":
https://en.wikipedia.org/wiki/Firewall_(engine)

2) On newer cars (starting in the late twenty-teens) there can be a diagnostic firewall, generally implemented in the gateway, that prevents scan tools from performing certain functions unless specific conditions have been met. These conditions can vary from just requiring the hood ("bonnet") to be open to requiring a cyrptograhically secure authorization from the manufacturer. Specifics vary by manufacturer, model, and model year. This is obviously not applicable to the 20+ year old car being discussed in this thread.

-Uwe-

 

[Dr Sheldon]

It can refer to two things.

1) Universally, it's the metal between the cabin and the engine bay which keeps engine fires

2) On newer cars

-Uwe-

Ok

1. We call that the Bulkhead - Never ever in 45 years heard it referred to as anything else - that solves that !!

2 Yes! Aware of that ...

 

[Dr Sheldon]

As in - the clutch cable in the Mk 2 Golf would tear out of the bulk head and would need a patch welded in to fix it - RHD

Did you see that on the LHD cars @Uwe ?

 

[Uwe]

Did you see that on the LHD cars @Uwe ?

Not that I'm aware of. But RHD was has always struck me as an engineering afterthought on VAG cars. My guess is the firewall on them was engineered to take the stress of the clutch cable on LHD cars with appropriate stiffening/strengthening in that location, while on RHD cars, they just drilled a new hole in whatever metal was there.

-Uwe-

 

[Dr Sheldon]

Not that I'm aware of. But RHD was has always struck me as an engineering afterthought on VAG cars. My guess is the firewall on them was engineered to take the stress of the clutch cable on LHD cars with appropriate stiffening/strengthening in that location, while on RHD cars, they just drilled a new hole in whatever metal was there.

-Uwe-

Indeed yes !!

The ford Fiesta of that Era was the same - The Servo and Master Cylinder were on the Left so all linkages were linear. For RHD there was a complex Ikea type hash. Compared to the LHD the pedal was never as good - Flakey at best ?

 

[Dr Sheldon]

Not that I'm aware of. But RHD was has always struck me as an engineering afterthought on VAG cars. My guess is the firewall on them was engineered to take the stress of the clutch cable on LHD cars with appropriate stiffening/strengthening in that location, while on RHD cars, they just drilled a new hole in whatever metal was there.

-Uwe-

And then the near 90 Degree angle across the "firewall" and out again to the box

 

[atbro199]

Here is the auto scan.

The "No activity" is new as it had been the "internal resistance is too high" several times previously. I'm also including a few read-outs from the measuring blocks below this.

Note: MIL is still off but the "no activity" code is pending. I may take it for emissions tomorrow just to see what happens despite the readiness codes.

Sunday,25,August,2024,16:24:34:42314
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 24.7.0.0 (x64)
Data version: 20240715 DS356.3
www.Ross-Tech.com


VIN: WAUXU64B43N116243   License Plate:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 4B (4B - Audi A6/S6/RS6/allroad C5 (1998 > 2005))
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
          75 76 77
 
VIN: WAUXU64B43N116243  
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 077-907-559-ANK.clb
   Part No: 4D0 907 560 CN
   Component: 4.2L V8/5V      G   0001
   Coding: 06752
   Shop #: WSC 24253
   VCID: 74E783CC441E6536D7-5140
   WAUXU64B43N116243     AUZ7Z0C2391716

3 Faults Found:
16825 - EVAP Emission Control Sys
            P0441 - 35-10 - Incorrect Flow - Intermittent
18010 - Power Supply Terminal 30
            P1602 - 35-10 - Voltage too Low - Intermittent
16544 - Oxygen (Lambda) Sensor B2 S2
            P0160 - 35-00 - No Activity
Readiness: 0110 0001

-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 01L-927-156.lbl
   Part No: 4B0 927 156 FH
   Component: AG5 01L 4.2l5V  USA 1314
   Coding: 00002
   Shop #: WSC 02334
   VCID: 72EB85D43E0A6B06C5-5140

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 4B0-614-517.lbl
   Part No: 4B0 614 517 E
   Component: ABS/ESP allrad      3428
   Coding: 06397
   Shop #: WSC 31414
   VCID: 2345B090B170B28EFE-5140

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 4B0-820-043-MY2.lbl
   Part No: 4B0 820 043 AR
   Component: A6-Klimavollautomat 0208
   Coding: 00010
   Shop #: WSC 00000
   VCID: 6ADB9DB416DAA3C67D-2586

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 4B0-959-655-AI84.lbl
   Part No: 4B0 959 655 Q
   Component: Airbag 8.4EP        3001
   Coding: 0000607
   Shop #: WSC 02334 785 00200
   VCID: 3E7361E46AD2FF66F1-515E

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 4B0-920-xxx-17.lbl
   Part No: 4B0 920 981 Q
   Component: KOMBI+WEGFAHRS. VDO D12
   Coding: 03283
   Shop #: WSC 62859
   VCID: 346743CC049E253617-5140
   WAUXU64B43N116243     AUZ7Z0C2391716

1 Fault Found:
01304 - Radio
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 35: Centr. Locks        Labels:. 4B0-962-258.clb
   Part No: 4B0 962 258 M
   Component: Central Lock/Alarm  D38
   Coding: 15977
   Shop #: WSC 02334
   VCID: 336540D00190220E0E-4EEA

3 Faults Found:
01559 - Drivers Door
            59-00 - Can't Unlock
01561 - Rear left door
            59-10 - Can't Unlock - Intermittent
01562 - Rear right door
            59-00 - Can't Unlock

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr        Labels: None
   Part No: 4B0 959 760 B
   Component: Sitzmemory R1 F     0204
   Coding: 00001
   Shop #: WSC 00000
   VCID: 2C575BACDCAE7DF64F-4B00

1 Fault Found:
00668 - Supply Voltage Terminal 30
            07-10 - Signal too Low - Intermittent

-------------------------------------------------------------------------------
Address 37: Navigation        Labels: 4B0-919-887-BNS4.lbl
   Part No: 4B0 919 887 E
   Component: BNS 4.2 H05    BNO 0050
   VCID: 35617EC80FE43C3E20-4AE8

1 Fault Found:
65535 - Internal Control Module Memory Error
            00-00 - -

-------------------------------------------------------------------------------
Address 55: Headlight Range        Labels: 4Z7-907-357.lbl
   Part No: 4Z7 907 357
   Component: dynamische LWR       D09
   Coding: 00050
   Shop #: WSC 02334
   VCID: 0407D30C14BE55B6E7-4B4C

No fault code found.

End-------------------------(Elapsed Time: 05:14)--------------------------

Measuring blocks:

                Address 01: Engine  (4D0 907 560 CN)

16:01:45 Group 036: Lambda Control (Sensor Readiness - After Catalyst)
  0.665 V  Sensor Voltage Bank 1 Sensor 2
  B1-S2 OK  Result Lambda Availability
  0.420 V  Sensor Voltage Bank 2 Sensor 2
  B2-S2 Not OK  Result Lambda Availability

16:01:45 Group 041: Lambda Control (Lambda Sensor Heating Bank 1)
  0.20 kOhm  Resistance Bank 1 Sensor 1
  Htg. S1 ON  Heater Condition Bank 1 Sensor 1
  0.10 kOhm  Resistance Bank 1 Sensor 2
  Htg. S2 ON  Heater Condition Bank 1 Sensor 2

16:01:45 Group 042: Lambda Control (Lambda Sensor Heating Bank 2)
  0.40 kOhm  Resistance Bank 2 Sensor 1
  Htg. S1 ON  Heater Condition Bank 2 Sensor 1
  25.50 kOhm  Resistance Bank 2 Sensor 2
  Htg. S2 ON  Heater Condition Bank 2 Sensor 2

Note the measured resistance for Bank 2 Sensor 2. The voltage for that sensor also never fluctuates like Bank 1 sensor 2.

 

[Uwe]

I may take it for emissions tomorrow just to see what happens despite the readiness codes.

With three readiness bits not set, I'd be very surprised if it passes.

Note the measured resistance for Bank 2 Sensor 2.

25.50 kOhm Resistance Bank 2 Sensor 2

Does this change with that sensor unplugged?

-Uwe-

 

[atbro199]

I unplugged B2S2 (brown connector) and here are the data. Note: B1S2 didn't have a resistance value and both B1S2 and B2S2 heating were flickering ON and OFF every few seconds. Couldn't really get a good output of that activity.

                Address 01: Engine       Labels: 077-907-559-ANK.CLB
Control Module Part Number: 4D0 907 560 CN
  Component and/or Version: 4.2L V8/5V      G   0001
           Software Coding: 06752
            Work Shop Code: WSC 24253 
           Additional Info: WAUXU64B43N116243     AUZ7Z0C2391716
                      VCID: 74E783CC441E6536D7-515E
4 Faults Found:

16825 - EVAP Emission Control Sys
            P0441 - 35-10 - Incorrect Flow - Intermittent
18010 - Power Supply Terminal 30
            P1602 - 35-10 - Voltage too Low - Intermittent
16544 - Oxygen (Lambda) Sensor B2 S2
            P0160 - 35-00 - No Activity
17530 - Oxygen (Lambda) Sensor Heating; B2 S2
            P1122 - 35-00 - Open Circuit

Readiness: 0110 0001

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


                Address 01: Engine  (4D0 907 560 CN)

16:59:43 Group 036: Lambda Control (Sensor Readiness - After Catalyst)
  0.445 V  Sensor Voltage Bank 1 Sensor 2
  Test OFF  Result Lambda Availability
  0.415 V  Sensor Voltage Bank 2 Sensor 2
  Test OFF  Result Lambda Availability

16:59:43 Group 041: Lambda Control (Lambda Sensor Heating Bank 1)
  0.30 kOhm  Resistance Bank 1 Sensor 1
  Htg. S1 ON  Heater Condition Bank 1 Sensor 1
     Resistance Bank 1 Sensor 2
  Htg. S2 OFF  Heater Condition Bank 1 Sensor 2

16:59:43 Group 042: Lambda Control (Lambda Sensor Heating Bank 2)
  0.70 kOhm  Resistance Bank 2 Sensor 1
  Htg. S1 ON  Heater Condition Bank 2 Sensor 1
     Resistance Bank 2 Sensor 2
  Htg. S2 OFF  Heater Condition Bank 2 Sensor 2

 

[Dr Sheldon]

The "No activity" is new as it had been the "internal resistance is too high" several times previously. I'm also including a few read-outs from the measuring blocks below this.

Note: MIL is still off but the "no activity" code is pending. I may take it for emissions tomorrow just to see what happens despite the readiness codes.

So you now have two bad sensors ?? Just failed in different ways

Bright side is that wiring and ECU are reactive and correct ??!!

 

[Uwe]

I unplugged B2S2 (brown connector) and here are the data.

So it's not a completely broken wire, but either the heater in the sensor has really high resistance, or one of the wires or connectors does.

-Uwe-

 

[atbro199]

So it's not a completely broken wire, but either the heater in the sensor has really high resistance, or one of the wires or connectors does.

-Uwe-

Since the Bosch 16073 oxygen sensor is "universal" it comes with a black female connector that I'm supposed to swap with the brown one (pull pins out and reinstall in black one), as the brown one has a notch and the new black one does not. The previous owner had jammed the O2 male connector into the brown female connector, so I did the same. It still clicks and appears to be a good connection, so I have been dismissing it. But could the car be VERY, VERY PICKY with this and throw the code? I had originally dismissed it as it appears to be a good connection, but I am having a hell of a time trying to "de-pin" the brown connector with my terminal toolkit, and a "European" terminal tool is coming tomorrow that I'll try.

 

[atbro199]

Pics of said connector.

 

[Dr Sheldon]

Does this sensor need an input from Atmosphere that really should not be choked when making the "Universal! Connection.. ?

Some O2's need more than Electric ??

 

[atbro199]

Does this sensor need an input from Atmosphere that really should not be choked when making the "Universal! Connection.. ?

Some O2's need more than Electric ??

I don't believe so..?

 

[Crasher]

Indeed yes !! WTF is a Firewall in a car ??

I expected you were being pedantic.

As in - the clutch cable in the Mk 2 Golf would tear out of the bulk head and would need a patch welded in to fix it - RHD

Did you see that on the LHD cars @Uwe ?

That was Golf 1, there’s no such thing as a Mk1 Golf (pedantism at its finest), the Golf 2 clutch cable hole is in the plenum chamber in what VW call the “water box” and it passes into the engine bay via a hole in the “rip plate on front cross panel”, VW call the bulkhead the “cross panel”. The reaction point point for the RHD Golf 2 cable is actually part of the pedal box itself.

 

[Dr Sheldon]

The reaction point point for the RHD Golf 2 cable is actually part of the pedal box itself.

That rings a bell

For sure remember stitching washers in there to get the clutch pedal to work

 

[Crasher]

The clutch cable on the Golf 2 was a revelation over Golf 1, my business partner used to carry a spare around in his mother’s 76 1.3 as the eyelet fitting was always failing. The bulkhead reinforcement plate was a good quick fix but it never fitted very well, I used to take the adhesive off and use polyurethane sealant to bond it on. I had better stop now or Uwe will be slapping my legs for going off piste.

 

[atbro199]

My euro terminal tool arrived, and after an hour of pushing and pulling the wires in the brown connector, I cannot get more than one to release. The one I was able to release was the same one from Sunday, so it's special. But the other three (signal, two heater wires) aren't budging whatsoever. Also tried a trimmed hairpin without success. Not winning this battle!

 

[atbro199]

Back after a quick trip and my wife was free to help me swap out the oxygen sensor with another one I bought. This time I purchased it from Rock Auto and it came in a newer box with a more recent copyright date (2018) whereas the two original boxes I bought from Amazon had a copyright of 2012. I'm sending the Amazon ones back as defective. I also measured the heater circuit in the new one and it came back with 8.9 ohms. Better than the others but not great. I don't know if this is an issue or not.

I say defective because after I installed the new oxygen sensor, it began working as intended. The voltage fluctuated as the other bank does and the test came back as OK. See below for some output.

I cleared any DTCs and will drive it this week to hopefully set the readiness.

However, after my second drive, the car had a code (no MIL yet): P1140 Oxygen (Lambda) Sensor; B2 S2: Internal Resistance too High

I'll give it another drive before doing an auto scan, but here are two group readouts I grabbed before clearing DTCs and readiness:

                Address 01: Engine  (4D0 907 560 CN)

16:59:50 Group 036: Lambda Control (Sensor Readiness - After Catalyst)
  0.580 V  Sensor Voltage Bank 1 Sensor 2
  B1-S2 OK  Result Lambda Availability
  0.520 V  Sensor Voltage Bank 2 Sensor 2
  B2-S2 OK  Result Lambda Availability

16:59:50 Group 042: Lambda Control (Lambda Sensor Heating Bank 2)
  0.30 kOhm  Resistance Bank 2 Sensor 1
  Htg. S1 ON  Heater Condition Bank 2 Sensor 1
  25.50 kOhm  Resistance Bank 2 Sensor 2
  Htg. S2 ON  Heater Condition Bank 2 Sensor 2

If the MIL appears with the same code, then it's going to a speed shop on Friday to get a more thorough diagnosis.