Efficiency Below Threshold - o2 sensor?

[Polobear6r]

So I got this check engine light I drove normal at a 100KM for about 40 minutes and suddenly the check engine came up. I cleared the code but a few days later I got the same code again while waiting for a stop sign. (autoscan below)

Is this a familiar code and does someone know where the fault is? My guess it is one of the 2 O2 sensors? (I believe in the Netherlands we call them lambdasensor ?)
Or is it the catalytic converter itself?
the autoscan says:
1 Fault Found:
6093 - Catalyst System; Bank 1
P0420 00 [237] - Efficiency Below Threshold

But is Bank 1 a fixed position? For example the Oxygen sensor that is mounted on the exhaust manifold? (and bank 2 the sensor after the catalytic converter?)

Is there a way to clean o2 sensors? I see some video's on youtube but do they work?

Code: Select all

Friday,11,December,2020,12:19:27:23303
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 20.12.0.1 (x64)
Data version: 20201125 DS322.1
www.Ross-Tech.com


VIN: WVWZZZ6R(removed for privacy reasons)   License Plate: 
Mileage: 241790km-150241mi   Repair Order: 



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


Chassis Type: 6R-VW25 (6N0)
Scan: 01 03 04 08 09 15 17 19 25 44

VIN: WVWZZZ6R(removed for privacy reasons)   Mileage: 241790km-150241miles

01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
 
-------------------------------------------------------------------------------
Address 01: Engine (J623-CGPB)       Labels:. 03E-906-019-CGP.clb
   Part No SW: 03E 906 019 M    HW: 03E 906 019 B
   Component: SIMOS11.1     H03 8949  
   Revision: --------    Serial number:               
   Coding: 00110016000400080000
   Shop #: WSC 00788 648 00255
   ASAM Dataset: EV_ECM12MPI02103E906019M 001007
   ROD: EV_ECM12MPI02103E906019A.rod
   VCID: 2E57F709714C42F4A0-807A

1 Fault Found:
6093 - Catalyst System; Bank 1 
          P0420 00 [237] - Efficiency Below Threshold
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 3
                    Mileage: 0 km
                    Date: 2000.00.00
                    Time: 00:00:00

                    Engine RPM: 836.00 /min
                    Normed load value: 19.2 %
                    Vehicle speed: 8 km/h
                    Coolant temperature: 86 °C
                    Intake air temperature: 20 °C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 13.507 V
                    Unlearning counter according OBD: 40
                    Test of catalytic converter: measured value-EFF_CAT_DIAG_OBD[1]: 1.140625
                    Cat. temperature: bank 1: 769.78751 °C
                    Engine RPM: 827 /min
                    Air mass: actual value:-MAF: 101.18 mg/stroke

Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104)       Labels:. 6R0-907-37x-ESP82.clb
   Part No SW: 6R0 907 379 AK    HW: 6R0 907 379 AF
   Component: ESP8.2i front H05 0001  
   Revision: --------    
   Coding: 210224E3217000B6842924EB84DA00401100
   Shop #: WSC 00788 648 00255
   VCID: 071962ADB27633BC43-8052

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC (J301)       Labels: 6R0-820-045-9AB.clb
   Part No SW: 6R0 820 045 F    HW: 6R0 820 045 F
   Component: Man AC         02 0101  
   Revision: 0002S 02    
   VCID: 316DEC7568725D0CBD-8064

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels:. 6R0-937-08x-09.clb
   Part No SW: 6R0 937 087 H    HW: 6R0 937 087 
   Component: BCM PQ25 H+4  H46 0230  
   Revision: BF046001    Serial number: 0394 035110798
   Coding: 7BB02BBF08A10048002008002D2B0C900040410F60060000200000000000
   Shop #: WSC 124697 483 00190
   VCID: 428FB3B9DDD4D69454-8016

   Subsystem 1 - Part No SW: 6R0 959 801 AB    HW: 6R0 959 801 AB  Labels: 6R0-959-801.CLB
   Component: J386__TSG_FT  008 1611 
   Serial number: KU0KU014061100014122
   Coding: 18BC30

   Subsystem 2 - Part No SW: 6R0 959 802 AD    HW: 6R0 959 802 AD  Labels: 6R0-959-802.CLB
   Component: J387__TSG_BT  008 1611 
   Serial number: KU0KU016061100013956
   Coding: 08BC30

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags (J234)       Labels:| 5K0-959-655.clb
   Part No SW: 6R0 959 655 K    HW: 6R0 
   Component: VW10Airbag022 H09 0020  
   Revision: --------    Serial number: 003GX00PVUS.
   Coding: 003232
   Shop #: WSC 00788 648 00255
   ASAM Dataset: EV_AirbaVW10BPAVW250 A01001
   ROD: EV_AirbaVW10BPAVW250_VW25.rod
   VCID: 4A9F9B99EDE40ED49C-801E

   Crash sensor for side airbag: driver side: 
   Serial number: 3575HRB404V0JR9KC0K6

   Front Passenger's Side Airbag Crash Sensor: 
   Serial number: 3585HRB40570ISD6CGHU

   Rear Side Airbag Crash Sensor (on driver's side): 
   Serial number: 3515RRB40530L9U4H1JK

   Passenger side rear thorax airbag crash sensor: 
   Serial number: 3525RRB405D0L2V2C8FL

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments (J285)       Labels:| 5K0-920-xxx-17.clb-SRI1
   Part No SW: 6R0 920 860 G    HW: 6R0 920 860 G
   Component: KOMBI         H03 0505  
   Serial number: 00000000000000
   Coding: 140200
   Shop #: WSC 00788 648 00255
   ASAM Dataset: EV_Kombi_UDS_VDD_RM09 A04113
   ROD: EV_Kombi_UDS_VDD_RM09_004_VW25.rod
   VCID: 387BD15183088C44FA-806C

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533)       Labels:. 6N0-909-901-6R.clb
   Part No SW: 6N0 909 901     HW: 6R0 937 087 
   Component: GW-K-CAN TP20 0230  
   Coding: 002200
   Shop #: WSC 124697 483 00190
   VCID: 70EB2971A3F81404F2-8024

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer (J334)       Labels:| 5K0-920-xxx-25.clb
   Part No SW: 5K0 953 234     HW: 5K0 953 234 
   Component: IMMO          H03 0505  
   Serial number:               
   Coding: 000000
   Shop #: WSC 00000 000 00000
   ASAM Dataset: EV_Immo_UDS_VDD_RM09 A03009
   ROD: EV_Immo_UDS_VDD_RM09_VW23.rod
   VCID: 6ADF3B198D24EED4BC-803E

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist        Labels: 6Q0-423-156.clb
   Part No: 6R0 423 156 B
   Component: LenkhilfeTRW        V277  
   Coding: 11250
   Shop #: WSC 00788  
   VCID: 2F69EA0DEA464BFCAB-807A

No fault code found.

End-------------------------(Elapsed Time: 02:00)--------------------------

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


                Address 01: Engine       Labels: 03E-906-019-CGP.clb
Control Module Part Number: 03E 906 019 M    HW: 03E 906 019 B
  Component and/or Version: SIMOS11.1     H03 8949
           Software Coding: 00110016000400080000
            Work Shop Code: WSC 00788 648 00255
              ASAM Dataset: EV_ECM12MPI02103E906019M 001007 (VW25)
                       ROD: EV_ECM12MPI02103E906019A.rod
                      VCID: 2E57F709714C42F4A0-807A
1 Fault Found:

6093 - Catalyst System; Bank 1 
          P0420 00 [237] - Efficiency Below Threshold
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 3
                    Mileage: 0 km
                    Date: 2000.00.00
                    Time: 00:00:00

                    Engine RPM: 836.00 /min
                    Normed load value: 19.2 %
                    Vehicle speed: 8 km/h
                    Coolant temperature: 86 °C
                    Intake air temperature: 20 °C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 13.507 V
                    Unlearning counter according OBD: 40
                    Test of catalytic converter: measured value-EFF_CAT_DIAG_OBD[1]: 1.140625
                    Cat. temperature: bank 1: 769.78751 °C
                    Engine RPM: 827 /min
                    Air mass: actual value:-MAF: 101.18 mg/stroke


Readiness: 0000 0000

[RUM4MO]

No, "bank 1" in your "3 in line engine" is the only bank, the "bank 1" and "bank 2" is for a Vee configuration engine.

Sensor 1 is pre cat and sensor 2 is post car sensor, so your car has S1 B1 and S2 B1 for before and after the cat, we call these sensors Lambda sensors as well as they measure the Lambda of the exhaust.

Edit:- if there was a functional failure detected for either the S1 B1 or the S2 B1 then VCDS should have been able to report that and report it before the car looked like it was under performing.

I've never had this problem but maybe you could view live data to see how the S1 B1 was behaving at the same time as viewing live data for the S2.

That car has run many miles/kms so maybe it is just a failed cat.

[d-ash]

That car has run many miles/kms so maybe it is just a failed cat.

... or failed sensor, as happened to my 1.2Tsi recently. It drove fine with the Engine Management light illuminated, but was using 20% more petrol than normal (demonstrating how the feedback from the sensors influences fuel mix). VW recommend replacing both sensors as there seems to be history of the second failing soon after the first. Cost nearly £500 !!

[RUM4MO]

That car has run many miles/kms so maybe it is just a failed cat.

... or failed sensor, as happened to my 1.2Tsi recently. It drove fine with the Engine Management light illuminated, but was using 20% more petrol than normal (demonstrating how the feedback from the sensors influences fuel mix). VW recommend replacing both sensors as there seems to be history of the second failing soon after the first. Cost nearly £500 !!

Well, I would hope in your situation, there were Lambda sensor fault codes stored, and so made sorting this out a bit more logical than just going with an idea, the pre cat sensor does have the ability to change the fuelling, that is its purpose, the post car sensor is only there to monitor the cat's performance and verify that the gases passing out of the cat are staying within emissions limits when they should be.

Edit:- in the OP's opening post the VCDS scan results clearly only indicate an issue with the cat, there are no stored Lambda sensors faults, so looking at the live data from both Lambda sensors would be useful in trying to work out what seems to be the most likely root cause.

[Polobear6r]

Thanks guys for the replies.

Well i guess i'll have to figure out how i can show live data and where to look for.