I've been struggling to diagnose the P2002 fault code that has appeared in the last few weeks every 100 miles or so.

The dpf seems fine with 36g of ash, regens every 170 miles or so down to just over 5% soot. Differential pressure at idle after a regen is around 5m/bar.

I have changed and adapted  the G450 differential pressure sensor with no improvement.

The car runs and drives perfectly with no smoke or soot in the exhaust.

There is 77k miles on the clock and i am concerned the egr cooler may be partially blocked as this is apparently common.

3 bottles of dpf cleaner in the tank over the last few weeks hasn't helped.

i've pulled the fault code activation data from my car.

 

P2002.

Freeze frame data
Product name Value Unit
Fault status 11101101
Fault priority 2
Fault frequency 1
Reset counter 255
Mileage 124891 Km
Date 2023.09.26
Time 12:44:33
Engine speed 2393.00 1/min
Normed load value 0.0 %
Vehicle speed 63 km/h
Coolant temperature 89 °C
Intake air temperature 101 °C
Ambient air pressure 1000 mbar
Voltage terminal 30 14.720 V
2019 (K)/Skoda/Superb 2016 >/Engine Test Time: 2023-09-27 09:45:42 Report ID: MAXIA20230927094542
www.autel.com MaxiCOM MK808S Page 2
Dynamic environmental data
20 96 28 18 F7 00 3B 19 3E
05 42 16 EC 05 3F 16 ED
05 46 17 F7 1F D7 17 F4
1F FE 19 6A 02 1A
Unlearning counter according OBD 40
Exhaust mass flow of low-pressure EGR, calculated 0.059
Differential pressure ratio, low-pressure EGR 134.6 kg/h
Exh.recircul. 2, differential pres.sensor 1 bank 1, adap.
value 134.3 hPa
Exhaust recirculat.2, different.press.sens.1 bank 1, raw
value 135.0 hPa
Exh.recircul.valve 1 bank 1, pos.feedback - Act.value 99.50 %
Exhaust recirc.valve 2 bank 1, posit.feedback - Act.value 99.98 %
Exh. gas recirc. 2, diff. press. sensor 1 bank 1, dyn. value 134.5

 

Does anyone with more knowledge than me about the code see anything in the data that may suggest the cause of the issue.

 

Thanks in advance.

 

Hi do you have the ability to read measured value blocks?. If you can what are the figures for measured and calculated soot?.

These are the figures immediately after a regen. 

My local diesel specialist is pretty sure it's the egr cooler that is blocked with adblue crystallisation.

He's replaced loads of them.

It's being replaced next week if confirmed.

The new modified egr coolers have larger oval holes to hopefully reduce the chance of blockage. 

Will add some Wynn's adblue additive as well as it's supposed to prevent crystallisation. 

 

Edited 3 October, 20232 yr by Jon_67

Hi, did you get this sorted?

Yes , it was the egr cooler small tubes blocked with soot and gunge.

The garage replaced the egr cooler and egr valve with new parts and it has been fine for the last 20k miles.

Total cost was £1110, but I think the egr valve was fine and replacement wasn't really needed. 

Cool thanks. 

I came across this, anyone know if bypassing the egr cooler would cause any issues further down the line?

 

 

I have heard bypassing the egr can cause overheating of the valves etc on some vag diesel models.

Plus stricter mot emission tests that may be brought in may cause a fail due to egr system delete. 

A software change cannot bypass an EGR, it's physically impossible.

 

It may prevent it from functioning, the EGR emulator/simulator on my vehicle does that, a company that misrepresents a product they offer rings warning bells with me.

 

I'm happy with the emulator solution because if one day it causes problems with the ECU I can very quickly and easily disconnect it and revert to the standard set up, the ECU programming has not been changed.

 

Well actually it has subsequently because I had a performance remap, I come from a long line of hypocrites!

7 minutes ago, Jon_67 said:

I have heard bypassing the egr can cause overheating of the valves etc on some vag diesel models.

Plus stricter mot emission tests that may be brought in may cause a fail due to egr system delete. 

I don’t think it’s an EGR delete as the EGR isn’t being blanked off.  From what I can tell, it’s just a remap that tells the ECU to ignore the temperature on the output of the EGR cooler.

 

Just wondering if the higher temperature gases being passed through would cause a problem as they obviously aren’t being cooled enough. 

12 minutes ago, Jon_67 said:

I have heard bypassing the egr can cause overheating of the valves etc on some vag diesel models.

 

Do you have a source for that or was it mechanics talk?

 

EGR may reduce combustion temperatures but the ambient air that it replaces  is also much cooler, modern valve materials were more than capable of withstanding combustion temperatures before EGR reduced them under certain limited operating conditions in any case EGR is supressed whenever a DPF regeneration is in progress to increase the exhaust gas temperatures, the exhaust valves can cope with those temperatures all day long.

 

Burnt exhaust valves are something from 50 years ago before ECU controlled fueling and ignition.

5 minutes ago, J.R. said:

 

Do you have a source for that or was it mechanics talk?

 

EGR may reduce combustion temperatures but the ambient air that it replaces  is also much cooler, modern valve materials were more than capable of withstanding combustion temperatures before EGR reduced them under certain limited operating conditions in any case EGR is supressed whenever a DPF regeneration is in progress to increase the exhaust gas temperatures, the exhaust valves can cope with those temperatures all day long.

 

Burnt exhaust valves are something from 50 years ago before ECU controlled fueling and ignition.

Thanks for the info. Do you have the egr cooler bypass remap?

7 hours ago, J.R. said:

the EGR emulator/simulator on my vehicle does that