NOX fault P20EE after EGR delete (and physical blank)

coopso

Member
VIP Member
T6 Pro
Hi all, immediately after getting my EGR mapped out and physically deleted, I drove 100 motorway miles with no issue.

On the very next trip, I was about 30 miles up the road (motorway) when the EML came on and so I stopped to do a check. Output:

Code:
P20EE [0x20EE]
Nitrogen oxide (NOx) sensor, catalyst, bank 1 - efficiency below threshold
Status: Confirmed
----------------------------
P0674 [0x0674]
Glow plug, cylinder 4 - circuit malfunction
Status: Pending
============================
19. CAN Gateway
No DTC found.
============================
09. Onboard supply control unit09. Onboard supply control unit
DTCs: 1
----------------------------
03303 [0x0CE7]
Status: Test is inhibited by other DTC, Validated and stored in non volatile memory
============================
02. Transmission control unit
No DTC found.
============================
03. ABS control unit
No DTC found.
============================
01. Engine control unit01. Engine control unit
DTCs: 2
----------------------------
15922 [0x003E32]
P067400: Cylinder 4 Glow Plug Circuit
Status: Test failed, Test failed (current drive cycle), Pending, Test failed since last DTC clear
----------------------------
31103 [0x00797F]
P20EE00: SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
SCR NOx Catalyst Efficiency Below Threshold Bank 1
P20EE00: SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear, Warning indicator requested
============================
08. Heater and climate08. Heater and climate
DTCs: 1
----------------------------
9470993 [0x908411] Archive (inactive)
Status: Confirmed
============================
0D. Slide Door Left (VW TP2.0)
No DTC found.
============================
10. Parking Assistant 2
No DTC found.
============================
13. Active cruise control
No DTC found.
============================
15. SRS
No DTC found.
============================
17. Dashboard
No DTC found.
============================
18. Additional heater
No DTC found.
============================
20. FLA
No DTC found.
============================
25. Immobilizer
No DTC found.
============================
36. Driver seat adjustment
No DTC found.
============================
5F. Electronic Information System 15F. Electronic Information System 1
DTCs: 7
----------------------------
01555 [0x000613]
B201A00: Checking software version management
Check software version management
Status: Test failed, Confirmed
----------------------------
00512 [0x000200]
B13A001: Speaker channel 1, Electrical error
Bass speaker, channel 1, open circuit (DC diagnostics)
Status: Test failed, Confirmed
----------------------------
00517 [0x000205]
B13A101: Speaker channel 2, Electrical error
Bass speaker, channel 2, open circuit (DC diagnostics)
Status: Test failed, Confirmed
----------------------------
00518 [0x000206]
B13A101: Speaker channel 2, Electrical error
Treble speaker, channel 2, open circuit (AC diagnostics)
Status: Test failed, Confirmed
----------------------------
00522 [0x00020A]
B13A201: Speaker channel 3, Electrical error
Bass speaker, channel 3, open circuit (DC diagnostics)
Status: Test failed, Confirmed
----------------------------
00523 [0x00020B]
B13A201: Speaker channel 3, Electrical error
Treble speaker, channel 3, open circuit (AC diagnostics)
Status: Test failed, Confirmed
----------------------------
00527 [0x00020F]
B13A301: Speaker channel 4, Electrical error
Bass speaker, channel 4, open circuit (DC diagnostics)
Status: Test failed, Confirmed
============================
61. Battery Regulation using CAN (VW TP2.0)
No DTC found.
============================
62. Rear left door electoronics (VW TP2.0)
No DTC found.
============================
69. Trailer functions
No DTC found.
============================
72. Rear right door electronics (VW TP2.0)
No DTC found.
============================
76. Parking assistant
No DTC found.
============================
78. Slide Door Right (VW TP2.0)
No DTC found.

Glow plug has been reported for about a year now, was going to sort that after having EGR delete. NOX error is a first though, haven't seen that in my ownership.

I will clear the code and report back on my next trip. Meanwhile, any thoughts?
 
I drove 100 motorway miles with no issue.

On the very next trip, I was about 30 miles up
Emission faults need time/miles/driving cycles to get into confirmed state - and manifest themselves as dash warning light.
If you had checked the fault most likely was at "pending" state already after the first journey. Just got confirmed on the second run.
 
Understood, thanks.

So is my best bet to clear it and hope it doesn't come back, or is there some diagnosis I should do whilst the fault code is present?
 
Just thought I should add my vehicle details in my signature in case they're relevant.
 
Is this not related to the EGR delete & map?

What does the map guy say?
 
He's miles away so not sure how soon I can bring it in - he's happy for me to do that though. Meanwhile I did reset the code and it has come back after two 30 mile motorway trips (Pending for now). Assume it's emissions related but wondering if there's any potential issues if I continue to drive it with the fault?
 
Last edited:
Why do the EGR delete and remap in the 1st place?

What issues did you have?

(Not getting in to the whole legality of running a modified emissions system)
 
Why do the EGR delete and remap in the 1st place?

What issues did you have?

(Not getting in to the whole legality of running a modified emissions system)
The EGR was starting to fail (not fully closing).

So it has been blanked and then deleted in the software, no other mapping (for performance or whatever).

If needed, I could replace it and re-enable. This was the best option for me.
 
What map?

Has it been properly mapped out?

Or a back street garage map?

Any idea what parameters have been changed to "map" the EGR out?
 
I'm a civilian so no idea how to answer those questions. Thanks for your interest, though! All I can say is I used a well reviewed business I found here on the T6 forum, well known for this type of work - and so I hope (and have no reason to believe otherwise) that the work was proper and not a back street map.
 
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