# Oxygen sensors and catalytic converter temperatures report in Measuring Blocks



## VgRt6 (Mar 8, 2002)

I'm trying to use my VCDS to manually set readiness codes for an upcoming OBDII emissions inspection. I'm having problems getting the Block 046 cat test to initiate because the cat temperature reported is too low. The temp needs to be 405°C or higher for the test to initiate. Mine is stuck at 15°C.
Here's the weird thing and my questions.
Block 034 is for the pre-cat O2 sensor and reports a realistic cat temp (300°C, 400°C, whatever). Block 036 is for the post-cat sensor and reports a cat temp of 15°C that doesn't change. Block 046 is for the cat and reports a cat temp of 15°C, which also doesn't change.
Does the ECU receive two different cat temp signals, one from each of the O2 sensors? Or does it only receive one signal from one of the sensors. Based on the temps that VCDS is reporting, it's possible that the pre-cat sensor is reporting the temp in Block 034 and the post-cat sensor is reporting the temp in Blocks 036 and 046. Or it's possible that only the pre-cat or post-cat sensor sends the only signal and for some reason the ECU is confused about it in Blocks 036 and 046. It's also possible that there is some wiring problem between the post-cat sensor and the ECU.
The pre-cat sensor checks out fine via the diagnostic test. The post-cat sensor has some miles on it and probably should be replaced. However, before spending $100 on a new sensor, I'd like to try and understand how the temps are reported and use that to try and diagnose if I do have a sensor problem, a wiring problem, or a problem with the ECU.
Any help is appreciated.


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: Oxygen sensors and catalytic converter temperatures report in Measuring Blocks (VgRt6)*

Generally the sensors report (so to speak) individual readings pre and post converter. If your rear O2s has not passed its self test, the temp readings may not be displayed. However, if there is a fault stored or set while running these tests the same will occur. 
Please include some vehicle details including make, model, year, etc. A complete AutoScan and the faults originally stored would also help.


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (Dana @ Ross-Tech)*

1999.5 Jetta GLS VR6. The N7 Emissions Service Action (to reset the sensitivity of the cat efficiency test) has been done on the car.
The Autoscan only produces one code - 16804 - Catalyst, Efficiency Below Threshold. I get this code intermittently. I specultate that it's happening when the cat temp in Blocks 036 and 046 are actually being reported correctly. This seems to happen at times, and the diagnostic tests actually run when it does happen. Problem is that the cat efficieny test fails and the CEL comes on. For some of the time though, the CEL is off and 16804 is reported to be intermittent. When this is occurring, the cat temp in Blocks 036 and 046 is fixed at 15°C.
I scanned the car yesterday and found the intermittent 16804 code (the CEL is currently off and the cat temp in 036 and 046 is 15°C). I cleared the code and then went to set the readiness codes. The TB adaptation passed and the pre-cat sensor test passed. The next test in the sequence is the post-cat test. This test would not initiate. I suspect it would not because the cat temp is too low. I then left the set readiness codes menu and tried to get the Block 036 and 046 tests to initiate manually in Basic Settings. Both blocks reported 15°C and neither test would initiate.
In a nutshell, for some reason I get real cat temps in Blocks 036 and 046 some of the time, and get 15°C the rest of the time. There is something intermittently wrong. I'm trying to diagnose if it's the post-cat sensor, wiring between the post-cat sensor and ECU, or is the ECU itself.


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## vwemporium (May 27, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

Hello 
I can diagnose the ECU here on the bench if you like.
I also have spares.
Have you verified your air-mass or air cleaner? 
It would be a good idea before looking so hard at the OXS or ecu.
Could you post an auto-scan?
Show me some logs of the tests in basic settings for readiness for
030-031- 034-036-041
Try a default
Best,
Jack


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

The AutoScan will show me what Ecm is installed, the current software level and the label file. I can check out the readiness script with that data, and possibly make some additional Basic Settings suggestions. 
Are you running the manual tests in Basic Settings with your foot on the brake only? Most AFPs will run like that. 
Edit: Sorry Jack, I didn't "save", it's not a competition










_Modified by Dana @ Ross-Tech at 3:55 PM 2-23-2010_


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (Dana @ Ross-Tech)*

It has the 018B ECM (end of the part number). I'll post the rest tonight.
Yes, I'm using the brake pedal to initiate the tests. I've done this on an individual block in Basic Settings, and also using the guided 'Set Readiness Codes' sequence, which prompts you to step on the brake.
I've done these tests with the VCDS for years and never had any issues other than this oddball with the erroneous cat temp and the tests not initiating because of it.


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (vwemporium)*

The MAF is fine and the air filter is new. Fuel trims and air mass are well within specs and are consistent during the times when the cat temps are correct and incorrect.
I'll run the Autoscan and logs and post the results.










_Modified by VgRt6 at 4:32 PM 2-23-2010_


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

Figures. I checked things tonight and the cat temps being reported are realistic. The temp reported in 034 is different than in 036 and 046 and the temps in 036 and 046 are the same. It makes sense that the pre-cat sensor is providing the temp in 034 and the post-cat sensor is proviing the temp in 036 and 046.
I tried to set the readiness codes. All tests initiated. The cat efficiency was around 0.57. Since it was above 0.55, Cat B1 Not OK was reported.
I also ran an Autoscan and logged the requested blocks. Here are the results.
VCDS Version: Release 908.1
Data version: 20091018
Tuesday,23,February,2010,21:17:46:41396
Chassis Type: 9M - VW Jetta IV
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
76

Mileage: 453970km/282083miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 021-906-018-AFP.lbl
Part No: 021 906 018 B
Component: MOTRONIC ME7.1 G 6782 
Coding: 00000
Shop #: WSC 09151 
1 Fault Found:
16804 - Catalyst System; Bank 1: Efficiency Below Threshold 
P0420 - 35-10 - - - Intermittent
Readiness: 0000 0000
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 1J0-907-37x-ABS.lbl
Part No: 1J0 907 379 H
Component: ABS/EDS 20 IE CAN 0001 
Coding: 03604
Shop #: WSC 00066 
No fault code found.
-------------------------------------------------------------------------------
Address 15: Airbags Labels: 1J0-909-60x-VW3.lbl
Part No: 1J0 909 609 
Component: C AIRBAG VW3 SG 0002 
Coding: 00067
Shop #: WSC 00066 
No fault code found.
-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1J0-919-xxx-17.lbl
Part No: 1J0 919 951 B
Component: A4-KOMBIINSTR. VDO V57 
Coding: 06262
Shop #: WSC 00000 
No fault code found.
-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 1J0-959-799.lbl
Part No: 1J0 959 799 AJ
Component: 61 Zentral-SG Komf. 0001 
Coding: 04096
Shop #: WSC 00066 
Part No: 1J1959801C
Component: 61 Tõrsteuerger. FS0001r 
Part No: 1J1959802D
Component: 61 Tõrsteuerger. BF0001B 
Part No: 1J4959811C
Component: 61 Tõrsteuerger. HL0001r 
Part No: 1J4959812C
Component: 61 Tõrsteuerger. HR0001r 
No fault code found.
End ---------------------------------------------------------------------
Tuesday,23,February,2010,21:34:42
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'030,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Bank 1,Bank 1,Bin. Bits,Bin. Bits,,,,,,,,,,
,TIME,Sensor 1,Sensor 2,,,TIME,,,,,TIME,,,,
Marker,STAMP,,,,,STAMP,,,,,STAMP,,,,
,0.01, 111, 110, , ,,,,,,,,,,
,0.46, 111, 110, , ,,,,,,,,,,
,0.93, 111, 110, , ,,,,,,,,,,
,1.32, 111, 110, , ,,,,,,,,,,
,1.79, 011, 110, , ,,,,,,,,,,
,2.23, 011, 110, , ,,,,,,,,,,
,2.61, 011, 110, , ,,,,,,,,,,
,3.04, 111, 110, , ,,,,,,,,,,
,3.49, 111, 110, , ,,,,,,,,,,
,3.97, 111, 110, , ,,,,,,,,,,
,4.39, 111, 110, , ,,,,,,,,,,
,4.77, 111, 110, , ,,,,,,,,,,
,5.28, 011, 110, , ,,,,,,,,,,
,5.77, 011, 110, , ,,,,,,,,,,
,6.17, 011, 110, , ,,,,,,,,,,
,6.67, 011, 110, , ,,,,,,,,,,
,7.14, 011, 110, , ,,,,,,,,,,
,7.49, 111, 110, , ,,,,,,,,,,
,7.89, 111, 110, , ,,,,,,,,,,
,8.36, 011, 110, , ,,,,,,,,,,
,8.82, 011, 110, , ,,,,,,,,,,
,9.19, 011, 110, , ,,,,,,,,,,
,9.59, 111, 110, , ,,,,,,,,,,
,10.09, 111, 110, , ,,,,,,,,,,
,10.53, 111, 110, , ,,,,,,,,,,
,10.91, 011, 110, , ,,,,,,,,,,
,11.27, 011, 110, , ,,,,,,,,,,
,11.79, 011, 110, , ,,,,,,,,,,
,12.25, 011, 110, , ,,,,,,,,,,

Tuesday,23,February,2010,21:34:23
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'031,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Lambda Control,Lambda Control,Bin. Bits,Bin. Bits,,,,,,,,,,
,TIME,Bank 1 (actual),Bank 1 (specified),,,TIME,,,,,TIME,,,,
Marker,STAMP,,,,,STAMP,,,,,STAMP,,,,
,0.01,1.000,1.000, , ,,,,,,,,,,
,0.40,0.992,1.000, , ,,,,,,,,,,
,0.91,1.000,1.000, , ,,,,,,,,,,
,1.34,0.992,1.000, , ,,,,,,,,,,
,1.73,0.992,1.000, , ,,,,,,,,,,
,2.12,0.992,1.000, , ,,,,,,,,,,
,2.60,0.992,1.000, , ,,,,,,,,,,
,3.09,0.992,1.000, , ,,,,,,,,,,
,3.50,0.992,1.000, , ,,,,,,,,,,
,3.90,0.992,1.000, , ,,,,,,,,,,
,4.38,0.992,1.000, , ,,,,,,,,,,
,4.83,0.992,1.000, , ,,,,,,,,,,
,5.22,0.992,1.000, , ,,,,,,,,,,
,5.61,1.000,1.000, , ,,,,,,,,,,
,6.08,0.992,1.000, , ,,,,,,,,,,
,6.56,0.992,1.000, , ,,,,,,,,,,
,6.92,0.992,1.000, , ,,,,,,,,,,
,7.38,0.992,1.000, , ,,,,,,,,,,
,7.86,0.992,1.000, , ,,,,,,,,,,
,8.31,0.984,1.000, , ,,,,,,,,,,
,8.70,0.984,1.000, , ,,,,,,,,,,
,9.21,0.984,1.000, , ,,,,,,,,,,
,9.65,0.992,1.000, , ,,,,,,,,,,
,10.04,0.992,1.000, , ,,,,,,,,,,
,10.40,0.992,1.000, , ,,,,,,,,,,
,10.88,0.992,1.000, , ,,,,,,,,,,
,11.35,0.984,1.000, , ,,,,,,,,,,
,11.73,0.992,1.000, , ,,,,,,,,,,
,12.10,0.984,1.000, , ,,,,,,,,,,
,12.63,0.984,1.000, , ,,,,,,,,,,

Tuesday,23,February,2010,21:33:56
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'033,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Lambda Control,Bin. Bits,Bin. Bits,Bin. Bits,,,,,,,,,,
,TIME,Bank 1 Sensor 1,,,,TIME,,,,,TIME,,,,
Marker,STAMP, %,,,,STAMP,,,,,STAMP,,,,
,0.01,0.8, , , ,,,,,,,,,,
,0.46,-3.1, , , ,,,,,,,,,,
,0.91,1.6, , , ,,,,,,,,,,
,1.27,-2.3, , , ,,,,,,,,,,
,1.76,1.6, , , ,,,,,,,,,,
,2.24,-2.3, , , ,,,,,,,,,,
,2.71,-2.3, , , ,,,,,,,,,,
,3.06,1.6, ,  , ,,,,,,,,,,
,3.57,-2.3, , , ,,,,,,,,,,
,4.04,1.6, , , ,,,,,,,,,,
,4.52,-2.3, , , ,,,,,,,,,,
,4.90,1.6, , , ,,,,,,,,,,
,5.38,-2.3, , , ,,,,,,,,,,
,5.82,1.6, , , ,,,,,,,,,,
,6.19,-2.3, , , ,,,,,,,,,,
,6.60,1.6, , , ,,,,,,,,,,
,7.08,-2.3, , , ,,,,,,,,,,
,7.53,-2.3, , , ,,,,,,,,,,
,7.88,1.6, , , ,,,,,,,,,,
,8.26,-2.3, , , ,,,,,,,,,,
,8.76,1.6, , , ,,,,,,,,,,
,9.21,-2.3, , , ,,,,,,,,,,
,9.55,1.6, , , ,,,,,,,,,,
,9.96,-2.3, , , ,,,,,,,,,,
,10.44,1.6, , , ,,,,,,,,,,
,10.90,-2.3, , , ,,,,,,,,,,
,11.26,1.6, , , ,,,,,,,,,,
,11.64,-2.3, , , ,,,,,,,,,,

Tuesday,23,February,2010,21:33:26
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'034,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Engine Speed,Catalytic Converter,Dynamic Factor,Result,,,,,,,,,,
,TIME,(G28),Bank 1 Temp.,Bank 1 Sensor 1,Lambda Aging,TIME,,,,,TIME,,,,
Marker,STAMP, /min,°C,,,STAMP,,,,,STAMP,,,,
,0.02,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,0.46,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,0.81,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,1.29,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,1.79,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,2.22,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,2.62,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,2.98,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,3.50,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,3.95,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,4.32,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,4.82,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,5.30,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,5.75,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,6.12,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,6.63,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,7.05,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,7.44,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,7.79,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,8.29,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,8.77,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,9.09,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,9.49,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,10.00,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,10.47,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,10.81,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,11.20,680,290.0,1.991,B1-S1 OK,,,,,,,,,,
,11.70,680,290.0,1.991,B1-S1 OK,,,,,,,,,,

Tuesday,23,February,2010,21:33:06
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'036,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Voltage,Temperature,Lambda Factor, ,,,,,,,,,,
,TIME,,,,,TIME,,,,,TIME,,,,
Marker,STAMP, V,°C,,,STAMP,,,,,STAMP,,,,
,0.02,0.700,300.0,1.000,B1-S2 OK,,,,,,,,,,
,0.48,0.715,300.0,1.000,B1-S2 OK,,,,,,,,,,
,0.97,0.665,300.0,1.000,B1-S2 OK,,,,,,,,,,
,1.34,0.705,300.0,1.000,B1-S2 OK,,,,,,,,,,
,1.82,0.640,300.0,1.000,B1-S2 OK,,,,,,,,,,
,2.27,0.705,300.0,1.000,B1-S2 OK,,,,,,,,,,
,2.74,0.710,300.0,1.000,B1-S2 OK,,,,,,,,,,
,3.13,0.700,300.0,1.000,B1-S2 OK,,,,,,,,,,
,3.63,0.675,300.0,1.000,B1-S2 OK,,,,,,,,,,
,4.04,0.650,300.0,1.000,B1-S2 OK,,,,,,,,,,
,4.46,0.695,300.0,1.000,B1-S2 OK,,,,,,,,,,
,4.84,0.625,300.0,1.000,B1-S2 OK,,,,,,,,,,
,5.32,0.695,300.0,1.000,B1-S2 OK,,,,,,,,,,
,5.78,0.645,300.0,1.000,B1-S2 OK,,,,,,,,,,
,6.15,0.710,300.0,1.000,B1-S2 OK,,,,,,,,,,
,6.58,0.655,300.0,1.000,B1-S2 OK,,,,,,,,,,
,7.11,0.710,300.0,1.000,B1-S2 OK,,,,,,,,,,
,7.53,0.695,300.0,1.000,B1-S2 OK,,,,,,,,,,
,7.92,0.685,300.0,1.000,B1-S2 OK,,,,,,,,,,
,8.37,0.695,300.0,1.000,B1-S2 OK,,,,,,,,,,
,8.87,0.685,300.0,1.000,B1-S2 OK,,,,,,,,,,
,9.26,0.730,300.0,1.000,B1-S2 OK,,,,,,,,,,
,9.59,0.710,300.0,1.000,B1-S2 OK,,,,,,,,,,
,10.07,0.705,300.0,1.000,B1-S2 OK,,,,,,,,,,
,10.58,0.605,300.0,1.000,B1-S2 OK,,,,,,,,,,
,10.97,0.680,300.0,1.000,B1-S2 OK,,,,,,,,,,

Tuesday,23,February,2010,21:32:47
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'037,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Engine Load,Sensor Voltage,Delta Lambda,Result,,,,,,,,,,
,TIME,,Bank 1 Sensor 2,Bank 1 Sensor 2,,TIME,,,,,TIME,,,,
Marker,STAMP, %, V,,,STAMP,,,,,STAMP,,,,
,0.02,15.8,0.675,-0.008,System OK,,,,,,,,,,
,0.50,15.8,0.710,-0.008,System OK,,,,,,,,,,
,0.94,16.5,0.650,-0.008,System OK,,,,,,,,,,
,1.32,16.5,0.700,-0.008,System OK,,,,,,,,,,
,1.70,16.5,0.610,-0.008,System OK,,,,,,,,,,
,2.20,16.5,0.695,-0.008,System OK,,,,,,,,,,
,2.69,16.5,0.655,-0.008,System OK,,,,,,,,,,
,3.15,16.5,0.670,-0.008,System OK,,,,,,,,,,
,3.50,16.5,0.690,-0.008,System OK,,,,,,,,,,
,4.01,16.5,0.660,-0.008,System OK,,,,,,,,,,
,4.42,16.5,0.710,-0.008,System OK,,,,,,,,,,
,4.82,16.5,0.680,-0.008,System OK,,,,,,,,,,
,5.18,16.5,0.715,-0.008,System OK,,,,,,,,,,
,5.67,16.5,0.685,-0.008,System OK,,,,,,,,,,
,6.13,16.5,0.700,-0.008,System OK,,,,,,,,,,
,6.48,16.5,0.645,-0.008,System OK,,,,,,,,,,
,6.89,16.5,0.700,-0.008,System OK,,,,,,,,,,
,7.33,16.5,0.655,-0.008,System OK,,,,,,,,,,
,7.66,16.5,0.705,-0.008,System OK,,,,,,,,,,
,8.13,16.5,0.675,-0.008,System OK,,,,,,,,,,
,8.48,16.5,0.680,-0.008,System OK,,,,,,,,,,
,8.97,16.5,0.605,-0.008,System OK,,,,,,,,,,
,9.49,16.5,0.645,-0.008,System OK,,,,,,,,,,
,9.93,17.3,0.705,-0.008,System OK,,,,,,,,,,
,10.28,17.3,0.675,-0.008,System OK,,,,,,,,,,
,10.76,17.3,0.705,-0.008,System OK,,,,,,,,,,
,11.25,17.3,0.675,-0.008,System OK,,,,,,,,,,

Tuesday,23,February,2010,21:32:28
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'041,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Resistance,Heater Condition,Resistance,Heater Condition,,,,,,,,,,
,TIME,Bank 1 Sensor 1,,Bank 1 Sensor 2,,TIME,,,,,TIME,,,,
Marker,STAMP,,, kOhm,,STAMP,,,,,STAMP,,,,
,0.02, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,0.37, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,0.75, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,1.25, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,1.67, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,2.10, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,2.43, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,2.95, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,3.41, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,3.78, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,4.14, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,4.66, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,5.11, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,5.56, ,Htg. S1 OFF,0.10,Htg. S2 ON,,,,,,,,,,
,5.92, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,6.45, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,6.93, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,
,7.37, ,Htg. S1 ON,0.10,Htg. S2 ON,,,,,,,,,,

Tuesday,23,February,2010,21:31:02
021 906 018 B,,MOTRONIC ME7.1 G 6782,
,Group A:,'046,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Engine Speed,Catalytic Converter,Catalytic,Result,,,,,,,,,,
,TIME,(G28),Bank 1 Temp.,Conversion Bank 2,Cat. Conversion,TIME,,,,,TIME,,,,
Marker,STAMP, /min,°C,,,STAMP,,,,,STAMP,,,,
,0.42,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,0.80,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,1.30,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,1.79,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,2.21,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,2.63,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,3.12,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,3.52,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,3.93,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,4.30,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,4.81,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,5.25,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,5.67,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,5.97,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,
,6.52,680,315.0,0.555,Cat B1 Not OK,,,,,,,,,,


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## vwemporium (May 27, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

And the winner is a new CAT, sorry.
I have AFT in stock and OEM.
best,
Jack
[email protected]


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (vwemporium)*

Thanks, Jack.
I know the cat is borderline bad. Sometimes it passes and sometimes it doesn't. I can pass emissions testing though by setting the readiness codes during the window when it cat amplitude is on the lower end of the threshold and then drive down to the inspection station immediately.
What has me confused is why sometimes the cat temp reported by my post-cat sensor is stuck at 15°C. Unfortunately, the logs and Autoscan above are from when this wasn't happening, so they're likely useless for diagnosing the stuck too low temp.
Do the logs above suggest that the post-cat O2 sensor is working properly, at least intermittently? I think I'm going to replace the sensor regardless and see if that helps. The sensor has 160k miles on it, so it couldn't hurt. I already have a new pre-cat sensor in the garage waiting to go in, so I might as well replace both.
I'm running a MKIII downpipe with separate TT cat (MKIII style, but piping angle and length appropriate for the MKIV exhaust). I'd rather just replace the cat than install another new one-piece DP/cat unit. Not only should just the cat be cheaper, but I don;t have a lift and can't get the car high enough to get the one piece in.


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

I replaced the post-cat sensor this past weekend with a Bosch 16121 (OEM fit) sensor. The cat now passes with an amplitude of 0.337.
Very strange.


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: Oxygen sensors and catalytic converter temperatures ... (VgRt6)*

Thanks for the update. That explains the intermittent temp. readings, but I would have expected a catalyst test failure with a fresh rear O2s. The N7 update programming may have actually corrected the problem now that both O2 sensors are responding properly.
I would run out and get the emissions test done now


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures ... (Dana @ Ross-Tech)*

I'm going tomorrow.








Another weird thing is that when I first started monitoring Blocks 036 and 046 while driving home yesterday (with the new sensor), the temp was initially fixed at 15°C. I thought nothing had changed with the new sensor. After 2-3 minutes, it started to go up top slowly to normal temperature. It was 500°C plus during the cat test.


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures report in Measuring Blocks (VgRt6)*

Now I have no idea what's going on.
Before driving to the emissions test this morning, I figured I'd better check that there was still no cat code in memory. There was. Crap. I ran the diag. test and the cat failed miserably (amplitude around 0.7). I've noticed that the ampltudes tend to be lower with my cat when it's hotter, so I cleared codes and took the cat on the highway to get the cat temp higher during the test. I ran the test about a dozen times, clearing codes after each time the test failed. The amplitude was 0.57 the first time, so the test failed. For the next ten or so tests, the amp was actually below 0.5, but CAT B1 NOT OK was still reported. The amplitude was as low as 0.28 for some of the tests, and all were below 0.44. CAT B1 NOT OK was reported everytime. Even with that many failures and code in memory, the CEL has not come on yet.
It was bad enough when I couldn't get the tests to initiate or pass, but not they do initiate and the amplitude is in spec, but the test still fails. The post-cat sensor voltage is jumping from about 0.1 to 0.8 with periods of relatively steady voltage around 0.7 (what I would expect if the cat were good). There's something intermittently going on that's causing the cat to fail, or maybe the cat really is bad and the fluke is actually causing it to intermittently pass.
This is really frustrating.


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## VgRt6 (Mar 8, 2002)

*Re: Oxygen sensors and catalytic converter temperatures report in Measuring Blocks (VgRt6)*

The CEL is now on.


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## need_a_VR6 (May 19, 1999)

*FV-QR*

Clear it and drive right in, it'll pass.


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (need_a_VR6)*

Not down here it won't. They scan to check that all readiness codes are 0 and there are no codes in memory. If they didn't do that, I wouldn't have wasted hours of my life on this.


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## need_a_VR6 (May 19, 1999)

*FV-QR*

Straight from http://www.mde.state.md.us/ass...e.pdf

_Quote, originally posted by *Maryland* »_Vehicles with three or more unset readiness monitors (noncontinuous
monitors only) for model years 1996 to 2000, or
two or more for model year 2001 and newer vehicles, will be
designated as "Unable to Complete OBD Testing." Motorists
whose vehicles are designated as "Unable to Complete OBD
Testing," will be granted an extension and advised to return
for testing after one week of normal driving.
The presence of unset readiness monitors does not mean
that a vehicle will fail the OBD test. Rather, unset readiness
codes indicate that the vehicle cannot be fully OBD
tested because all the information needed to make a pass/
fail determiniation is not available.
If a motorist returns after one week of normal driving and
the vehicle still exceeds the allowable number of unset
readiness monitors, the vehicle will be passed or failed
based on the OBD pass/fail criteria.

That means you can have two unset readiness monitors and still pass.

__
Image uploading. Refresh page to view


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (need_a_VR6)*

I just found that PDF too. Don't ask me why I questioned you ...


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (VgRt6)*

I can run the diag tests and get all to set except for the cat. I'm going to do that and take it in.


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (VgRt6)*

Any ideas why the amplitude would max out at 0.47 (below the limit of 0.5), but CAT B1 NOT OK would still be reported? Doesn't make sense.
I'm going tomorrow to try and get the car to pass with the cat readiness code not set. We'll see what happens.


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## vwemporium (May 27, 2002)

*Re: FV-QR (VgRt6)*

Cross-check between OXS is why also maybe a SP air-mass.
The value must be as low as possible, the closer to zero amplitude the better.
Best,
Jack


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (vwemporium)*

So even though an amplitude of 0.5 is the threshold for the cat not being efficient enough (yes, lower would be better), the cat can still "not be efficient enough" if the amplitude is below 0.5? That's what I don't understand. Is it a strict threshold or not?


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## VgRt6 (Mar 8, 2002)

*Re: FV-QR (VgRt6)*

Good news, bad news.
Good news is that the car passed emissions testing with one readiness code (for the cat) not set.








Bad news is that the problem with the cat still exists.









For informational purposes only (not endorsing this or saying that I did it) ...
The trick for doing this (at least in states that do not require all readiness codes to be set to pass the OBDII emissions test, like Maryland), is erasing all codes, running all of the diagnostic tests for the readiness codes that will pass without logging a DTC, and then getting to the test station before any of the diagnostic tests for the remaining readiness codes (those that will log a DTC when completed) have a chance to run and finish. This is relatively easy to do if the cat is bad. The cat diagnostic test will only initiate at engine speeds above idle and requires an extended period (couple of minutes) of nearly constant throttle to complete. If the test is running (TEST ON is displayed) and throttle is increased or decreased too much, the test is canceled (TEST OFF is displayed). This behavior makes it a piece of cake to drive to the test. While driving, monitor Block 046. If TEST OFF changes to TEST ON in Field 4, simply let off the throttle to get the test to cancel. Works every time. Since the test will not initiate at idle, sitting at red lights, or even for an extended period of time in line at the testing station is not a concern.


_Modified by VgRt6 at 10:33 PM 3-16-2010_


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: FV-QR (VgRt6)*

I'm glad you got the emissions test done! 
Sorry to hear about the catalyst


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## jordankersten (Dec 1, 2008)

Did you figure out a solution to this? I am having a similar issue. I get a P0420 code after a new cat (9 months old) and 2 new O2 sensors. My cat amplitude gets as high as .8 and it still passes...but sometimes it fails.


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## jetta 971 (Jul 25, 2009)

VgRt6 said:


> Good news, bad news.
> Good news is that the car passed emissions testing with one readiness code (for the cat) not set.
> 
> 
> ...


 Sorry to tell you this, but You need New CAT.


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## jetta 971 (Jul 25, 2009)

jordankersten said:


> Did you figure out a solution to this? I am having a similar issue. I get a P0420 code after a new cat (9 months old) and 2 new O2 sensors. My cat amplitude gets as high as .8 and it still passes...but sometimes it fails.


Did you put original CAT from Dealer?


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## jordankersten (Dec 1, 2008)

Yes, the dealer replaced the cat last August under warranty.


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## jetta 971 (Jul 25, 2009)

Go back to dealer again. You should be under warranty for that new one.
Also lot of people will put 87 octane fuel ,witch is not good for these cars. 2.0L engine is minimum 89 and 1.8L and VR6 is 91.
Lower octane fuel will damage CAT.
Also Fuel from anything but Shell, Valero , Mobil, Or Chevron is not good choice for any car.


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