Exhaust Gas Temp Sensor & DPF Problems

Hi everyone I have a problem with my Audi A3 2.0 TDI 170 Quattro. The issue is with 3 exhaust gast temp sensors and today the dpf warning came on. I did a scan with VCDS and got the fault code p2o80 exhaust gas temp sensor bank 1 sensor 1. I changed this this cleared the fault and everything was ok for a week or so, the mil light came back on so I did another scan and now I have 3 egts showing as faulty including the original fault of sensor 1 bank 1. Here is the scan.


VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.4.1.0 (x64)
Data version: 20200331 DS317.0
www.Ross-Tech.com


VIN: WAUZZ License Plate:



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Address 01: Engine Labels: 03L-906-018-CFF.clb
Control Module Part Number: 03L 906 018 AL HW: 03L 906 018 AG
Component and/or Version: R4 2,0L EDC H24 7764
Software Coding: 00190032042701080000
Work Shop Code: WSC 65535 000 00000
ASAM Dataset: EV_ECM20TDI01103L906018AL 003003 (AU35)
ROD: EV_ECM20TDI01103L906018AL.rod
VCID: 74EC00BEDF4216261F-8020
3 Faults Found:

8187 - Exhaust Gas Temp Bank 1 Sensor 1 (G235)
P2080 00 [237] - Implausible Signal
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 230578 km
Date: 2000.00.00
Time: 00:00:00

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 8 °C
Intake air temperature: 9 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 11.000 V
Unlearning counter according OBD: 40
Exh.gas temp.sen 1: 699.8 °C
Exh.gas temp.sen 2: -0.0 °C
Exh.gas temp.sen 3: 446.0 °C
Exh.gas temp.sen 4: 3.3 °C
Shut-off timer: last engine shut-off time: 32798 s

13811 - Exhaust Gas Temperature Sensor; B1 S3
P242B 00 [237] - Range/Performance
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 230578 km
Date: 2000.00.00
Time: 00:00:00

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 8 °C
Intake air temperature: 9 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 11.000 V
Unlearning counter according OBD: 40
Exh.gas temp.sen 1: 699.8 °C
Exh.gas temp.sen 2: -0.0 °C
Exh.gas temp.sen 3: 446.0 °C
Exh.gas temp.sen 4: 3.3 °C
Shut-off timer: last engine shut-off time: 32798 s

13812 - Exhaust Gas Temperature Sensor 4 Bank 1
P246F 00 [237] - Implausible Signal
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 230578 km
Date: 2000.00.00
Time: 00:00:00

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 8 °C
Intake air temperature: 9 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 11.000 V
Unlearning counter according OBD: 40
Exh.gas temp.sen 1: 699.8 °C
Exh.gas temp.sen 2: -0.0 °C
Exh.gas temp.sen 3: 446.0 °C
Exh.gas temp.sen 4: 3.3 °C
Shut-off timer: last engine shut-off time: 32798 s


Readiness: 1 3 0 0 0
Saturday,16,May,2020,14:20:32:63801
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.4.1.0 (x64)
Data version: 20200331 DS317.0
www.Ross-Tech.com


Any help with this would be really appreciated. Thanks.

Hi everyone, Ive done some more investigating on the DPF with VCDS and checked the soot content which is zero. I have also done and back pressure test on the DPF and that is also zero psi. There are no fault codes for the DPF either but the warning light is still on. The car hasnt gone into limp mode either, there is no loss of power at all.

Has anyone had this problem? or know what I should check next? Thanks

desertstorm said:

monitor the readings from the sensors to see what they are doing. If the car hasn't run for a few hopurs then you woukld expect them to be close to ambient temp. The lower the sensor number the closer it is to the engine so usually you would expect sensor 1 to show the hottest and 4 the colest. You can see from the fault data sensor 2 and 4 are showing nearly 0 degrees.

Click to expand...

Hi desertstorm, I monitored the live data for all the egt's from cold to normal operating temperature and there were no anomalies. The temperature rose as expected. I believe there is no sensor 2 on the car, so it would just be sensor 4 with the low reading. When I did the live data sensor 4 was working as it should.
The faults are intermittent which makes it difficult to diagnose. I think I am going to have to buy a data logger to plug in and record the data though I am unsure which one to buy, any recommendations?

desertstorm said:

The EGT sensors are platinum RTD devices and can go intermittent. Could also be a wiring issue, but usually first place to start is the sensor. You probably have the best diagnostic tool at the moment. It's unusual to miss out a sensor on the car they usually have sensor 1 pre turbo in the exhaust manifold, sensor 2 post turbo pre cat, sensor 3 is either post cat pre DPF or post DPF if the cat and DPF are combined. And sensor 4 will be post DPF.

Click to expand...

I was thinking along the lines of a wiring issue as I cant see 3 sensors at fault at the same time, bearing in mind the original fault was sensor 1 bank 1 only which I changed with a new one from euro car parts. It was only after I changed sensor 1 that I got the faults with sensor's 3 & 4 and then after a few weeks the DPF warning light came on.
I am going to need wiring diagrams I think in order to move forward but dont have auto data.

desertstorm said:

They appear to all have a common earth point that is common to many other sensors. Then connect straight to the ECU.
As you say doesn't seem to be a temp sender 2.

Click to expand...

Thank you very much desert storm really appreciate the wiring diagram. Looks like the earth could be the issue, will have to do some continuity tests etc and go from there. I will report back my findings, Thanks again for the diagram.