Error codes P20E8 and U029E

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My Name: leandroherrera

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Hello. If anyone had the error codes P20E8 and U029E, simultaneously, please advice what this means and how to solve it. Could it be due to a filled up particles filter?
Thanks very much!!!
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My Name: C3CAR

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Hi

Do you have any symptoms with driving or anything that led you you to get the codes read?
My Name: leandroherrera

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Model: C3 2017-on. The new C3
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Engine Size: 1.4 (16v)
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C3CAR wrote: Sat Nov 02, 2019 4:55 pm Hi

Do you have any symptoms with driving or anything that led you you to get the codes read?
No driving simptoms. Only the "check engine" light on
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My Name: C3CAR

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P20E8 - Reductant Pressure Too Low - that is the eolys is not being pressurised.

It could be that the eolys is empty because it's not actually monitored for the level,

BUT

U029E is a CAN BUS fault, communication with the NOx reduction system and not because the level is low.

I would say you are getting P20E8 because you have U029E

So start with U209E CAN BUS fault with the eolys control system. Poor electrical connections, damaged wiring etc.
My Name: leandroherrera

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Joined: Sat Nov 02, 2019 4:37 pm
Model: C3 2017-on. The new C3
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Engine Size: 1.4 (16v)
Fuel Type: Diesel
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Trim Level: Stop & Start
Gearbox: Manual 5 speed
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leandroherrera wrote: Sat Nov 02, 2019 4:47 pm Hello. If anyone had the error codes P20E8 and U029E, simultaneously, please advice what this means and how to solve it. Could it be due to a filled up particles filter?
Thanks very much!!!
Thanks again. Do you know where the NOX B sesnsor is located? Also, the addblue sensor seems to be stuck... the tank is full but the addblue light is on!!!
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My Name: C3CAR

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Model: C3 2002-2005, Original shape model
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Fuel Type: Diesel
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Gearbox: Manual 5 speed
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Engine name: DV4 16-valve diesel (90 PS)
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C3CAR wrote: Sun Nov 03, 2019 7:53 pm Also, the addblue sensor seems to be stuck... the tank is full but the addblue light is on!!!
This is probably connected to the CAN BUS communication fault.

The NOx sensors are in the exhaust system, but it looks more like a communication CAN BUS fault than lots of different sensors and actuators going faulty.

U029E is the starting point.

You should check with a local Citroen dealer with your VIN for recalls regarding the electrical connections for the emissions system. The car is still new and problems like this may be covered by warranty or recall.
My Name: leandroherrera

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Model: C3 2017-on. The new C3
Year: 2018 (18)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 45000
Trim Level: Stop & Start
Gearbox: Manual 5 speed
DPF: Yes
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Engine name: BlueHDi (75 PS)
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C3CAR wrote: Sun Nov 03, 2019 10:53 pm
C3CAR wrote: Sun Nov 03, 2019 7:53 pm Also, the addblue sensor seems to be stuck... the tank is full but the addblue light is on!!!
This is probably connected to the CAN BUS communication fault.

The NOx sensors are in the exhaust system, but it looks more like a communication CAN BUS fault than lots of different sensors and actuators going faulty.

U029E is the starting point.

You should check with a local Citroen dealer with your VIN for recalls regarding the electrical connections for the emissions system. The car is still new and problems like this may be covered by warranty or recall.
My Name: markyg

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Year: 2015 (65)
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I have the same issue with Grand C4 Picasso 2.0 bluehdi.
Urea tank replaced in 2017 with new cap and it was running fine for about 10 months after I bought it in November 2018 at less then 50k km.
Then emissions fault with urea light blinking with 1200km left started popping up. Error code P20E8 and UO29E popped up. Made a visit to Citroen service centre and was told there is a wiring harness recall to solve issue. Had wiring harness replaced around September this year for free but service centre said have Nox sensor problem. So replaced Nox at my cost only to be told is a urea tank fault because U029E never went away.
Now waiting for latest gen of urea tank in January. Hopefully it's part of a recall.
My Name: leandroherrera

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Posts: 8
Joined: Sat Nov 02, 2019 4:37 pm
Model: C3 2017-on. The new C3
Year: 2018 (18)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 45000
Trim Level: Stop & Start
Gearbox: Manual 5 speed
DPF: Yes
LHD or RHD: LHD
Engine name: BlueHDi (75 PS)
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I finally had to have Citroen dealer to change the whole urea tank. They couldn´t look into the fault itself. I was charged around 1.000 punds, equivalent in chilean pesos. There was no guarantee.

This should probably make citroen redesign the whole system (tank, sensor and pump) beacause the systems failed too early in the life of the car. I guess there should be a recall to change the urea adding system.

Way too expensive; way too bad a product; way too irresponsible not to cover failures of the emmissions control system.
My Name: jnoasis86

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Model: C3 Picasso
Year: 2015 (15)
Engine Size: I dont know
Fuel Type: Diesel
Mileage: 93000
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Engine name: BlueHDi (75 PS)
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I had this problem with a 2015 C3 Picasso Ad-blue diesel.

Replacing the adblue cap ( blue cap) will fix the issue no need for a new adblue tank & pump.

Posting to help someone out there.

Cheers
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