Skoda Superb DPF exhaust temp 999

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Wildtypitch
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Joined: Wed Sep 23, 2020 9:44 pm

Skoda Superb DPF exhaust temp 999

Post by Wildtypitch » Thu Sep 24, 2020 1:42 am

Hi. Just started using the app today to get some more detail on my DPF issues. I've a Superb 1.6 TDI Greenline at around 140,000 miles. DPF warning light, couple more miles and glow plug light and performance limited.
Screenshot 2020-09-24 003526.jpg
Differential Pressure is being recorded and in line with engine load. Assumption: DPF Sensor working

Input gas Temp reading well but DPF Output gas temp Is stuck at 999. Seems like a sensor malfunction. Assumption: If it can't read the output temp is can't engage the regen or control the temp.

High pressure EGR closing. Not sure what to make of this, it's constant 100%. Does that mean it's completely open or recirculating at max?

So based on this I'm considering replacing the sensor myself as it's very accessible. Or might I be reading the data wrong? I've disconnected the exhaust temp sensor and checked the obd and I indeed get P246F (Exhaust Gas temp Sensor circuit range/performance) error. Plug it back in and no P246F error jus the existing P2463 (Particulate Filter B1). Perhaps when it goes and reports 999 temp it's still considered within range?
Screenshot_20200924-000513_MotorData OBD.jpg

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admin
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Re: Skoda Superb DPF exhaust temp 999

Post by admin » Thu Sep 24, 2020 1:31 pm

What's the soot mass calculated value? The error P2463 seems to be related to an eccessive soot accumulation, you can verify this reading the corresponding value. If you post a screenshot I can check.

The output gas temp is too high, but let to the app a margin of error, it isn't an official VAG diagnostic app, some parameters could be wrong, especially their calculation formula to convert raw data to decimal values.

I suggest you to give first a double check using a professional diagnostic tester, better using a VAG instrument to be absolutely sure.
The input and output gas temperatures, togheter with differential pressure, are parameters used to calculate the soot mass accumulation. I don't know what's exactly the calculation made by the ECU, but in case of sensor failures the ECU goes in a protection mode launching the regeneration very often to prevent the risk of fire. Is this happening to your car?

EGR closing value constantly at 100% means that the valve is always closed with no gas recirculation. Usually this happens when a regeneration is in progress (the gas recirculation reduces the combustion chamber temperature).

Wildtypitch
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Joined: Wed Sep 23, 2020 9:44 pm

Re: Skoda Superb DPF exhaust temp 999

Post by Wildtypitch » Thu Sep 24, 2020 5:06 pm

Thanks for the input

Soot Mass measured is a staggering 71.98g

Soot mass calculated is only 0.1g

vag data.jpg

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Re: Skoda Superb DPF exhaust temp 999

Post by admin » Thu Sep 24, 2020 5:43 pm

These values are completely out of sense and could be a clue of something not working well, personally I would check as soon as possible with a VAG tester or at least with a VCDS to confirm the values.

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