Adblue fault no restart after 650miles, Error codes P20BC,P20E8

[Doctor786]

I had this message 4 months ago as well but simple turn off the engine and restart again solved the issues but the same issues has come back last week but this time with engine management light as well. It started the countdown to 650 miles and when it got to 550 miles some how it disappeared but came back after I did almost 300 miles. So countdown is down to 600 miles again at the moment. I am getting 2 error codes.

P20BC : Reductant heater "A" control circuit high

P20E8 : Reductant pressure Too low.

Any ideas which heater is "A"? is it the one inside the adblue tank where I have to replace whole tank along side the heater or is it the one outside the tank connected to hose pipes and can be changed on its own. Any help will be much appreciated in advance. As a taxi driver I will be doing remaining 600 miles in just 3 days so need to get it fixed as soon as possible.

[jdragon]

Welcome to the forum.

When you first had the message 4 months ago, did you topup the adblue or continue to use the car. If you topped it up, how much did you put in?x

[Doctor786]

No I didn't because I only filled it week ago so I knew there was plenty of adblue in the tank. This time I have put 5 liters of adblue just to to be sure without any luck. However after putting 5 liters of adblue warning did disappear for 3 days before it came back. Is there any way to find out which one is heater A?. Thanks for the quick reply mate.

[jdragon]

This link might yield something useful, especially checking connectors.

https://pmmonline.co.uk/technical/resolving-an-audi-a4s-adblue-warning-fault/

I don't know about the heater reference 'A'. I've checked the A5 B9 erWIN manual and the only reference I can find to a heater is in the supply line for the V437 pump.

Might be helpful to post the full scan, if you have it.

[Doctor786]

4 hours ago, jdragon said:

This link might yield something useful, especially checking connectors.

https://pmmonline.co.uk/technical/resolving-an-audi-a4s-adblue-warning-fault/

I don't know about the heater reference 'A'. I've checked the A5 B9 erWIN manual and the only reference I can find to a heater is in the supply line for the V437 pump.

Might be helpful to post the full scan, if you have it.

I don't have full scan mate, 650 miles warning disappeared yesterday but came back again today. At least it reset back to 650 miles again. Car runs fine with out any issues and still doing dpf regens as normal.

[Andrei lukacs]

Hi i got a audi 2.0 tdi 2016 and the engine light came on related to a p20bc error. I had that 650 miles warning filled up with adblue and next day the warning light came on. What can be the issue?

[jdragon]

6 hours ago, Doctor786 said:

I don't have full scan mate, 650 miles warning disappeared yesterday but came back again today. At least it reset back to 650 miles again. Car runs fine with out any issues and still doing dpf regens as normal.

You're welcome. Sounds like everything is OK now then.

[Doctor786]

4 hours ago, jdragon said:

You're welcome. Sounds like everything is OK now then.

Sorry if you misunderstood me, problem is still there.  I still have engine management light on however no restart warning after 650 miles keep disappearing and than coming back. 

[ConnerMac92]

Hi,anyone got these problems resolved? I have same issue,had to garage twice and told can't find fault.light goes off and on when it wants,went off now came on and says no restart in 10 miles....being told its a simple fix then told its going to cost major if tank needs replaced.any advice appreciated.

[kim231234]

I had this for the past 3 years on a 2014 A6 Ultra, I have a feeling it's a software issue that Audi knows about but won't recall the car. I noticed it tends to happen when the fob battery is low. It has happened to me 3 times now and when I changed both the fob batteries, the fault clears.

[Philly-Red]

On 10/18/2022 at 10:42 AM, Doctor786 said:

Sorry if you misunderstood me, problem is still there.  I still have engine management light on however no restart warning after 650 miles keep disappearing and than coming back. 

Don’t suppose you got this sorted? I’m having the same problem on my 68 q5. Fault appears, clears itself for a bit then returns. It’s driving me mad.

[Magnet]

Hello Craig,

Are you addressing this to anyone in particular? 
If so, best to send them a PM. 
Kind regards,

Gareth.

[Zeus]

I had the same problem .. had to change and adblue tank & pump (come as one unit) and the ECU for it .. £1900 later, all is fine .. warranty company picked up the bill …

[AliH]

You need to add minimum of 5.7 litre and maximum you can add 24 litres to reset it. I would suggest topping up between 7-10 litres. Thanks. 

[Eprism]

I’ve got a similar problem with my 2016 A6 Ultra.

A few days ago, I got an EML come up on the dashboard.

On having it checked out I was told that it was to do with DPF pressure.

Now at times I’ve had the DPF Filter alarm come up and some hard driving has always cleared it.

My thoughts are that the DPF pressure would be related to the DPF Filter alarm but if it is what would the alarm sequence be. DPF filter alarm first and then pressure alarm or are these different?

Two days later I got an “AdBlu system fault with no start in 650 miles”.

I had topped up the AdBlu tank a week before and it only required 1.5 litres and has never had to have more than 2 litres added at any time.

I checked the tank and it was full.

As for the 650 miles warning I travelled around 35 miles and the 650 was not counting down and then it suddenly dropped to 600, is that the way it works?

Could the Pressure alarm and the AdBlu system faults be related and the high pressure is not allowing the AdBlu to be injected into the exhaust system?

Is it possible to reset the AdBlu system fault back to 650 again if it gets too low.

Your thoughts would be greatly appreciated folks.

[Ecosse68]

Had the same ad blue fault appear on my A6 68 plate , 62k, which I’ve had from new.   Specialist quote 1750 for repair and Audi have just quoted 1950 .  Have always been really pleased with the car and Audi’s but  Never expected this at all and until now wasn’t aware this was an issue.   Not happy to say the least.   So is every car owner with ad blue going to have ridiculous bills when the cars are 4+ years.   

[Eprism]

From what I can see this is a major issue.

[colinmf]

I had an intermittent Adblue warning on an A4 Allroad recently. Then I noticed a pattern. Initially I got the 650 miles warning which dismissed itself but was left with the smaller warning above the clocks with a spanner and the word  Adblue. This disappeared after 2-3 miles. So, an intermittent error message. 

If you get this do check state of battery charge. Low battery caused the error on mine, hence why it disappeared after 2/3 miles of driving. Put the battery on a trickle charge for a few hours and guess what - no faults shown.

I’d hate to think that a dealer would change parts and charge the customer when all that was needed was a fully charged battery…

 

Colin

Edited November 4, 2023 by colinmf

[Magnet]

Many thanks Colin. 
Good point, and one which we have promoted as a ‘first port of call’ for all warning light issues. 
One point I would add is that although recharging the battery will probably sort the issue, that resolution maybe relatively short lived, and indicative of a failing below par battery, which needs renewing - or at least subjecting to an efficiency check. 
Kind regards,

Gareth 

[colinmf]

Cheers Gareth. To be honest I’ve been doing more short runs recently so that probably will have been harsh on the battery but you’re right, I must keep an eye on it and probably will need to fork out for a replacement before too much longer - the winter months will be a test.

[Magnet]

Let us know when you are ready Colin, and we can probably point you in the direction of quality at competitive prices.

Kind regards,

Gareth. 

[Clio2_00]

Hi, I have the same issue ad blue error no restart in 650, I have done a lot of googling and found that Audi offer Audi Extended Emissions Warranty for up to 10 years/120k, has anyone used this?

 

https://www.audiwarrington.com/blog/2019/november/26/audi-extended-emissions-warranty-an-overview.htm#:~:text=Post emissions modified vehicles can,from the date of modification.

[Poweller]

On 11/4/2023 at 6:21 PM, colinmf said:

I had an intermittent Adblue warning on an A4 Allroad recently. Then I noticed a pattern. Initially I got the 650 miles warning which dismissed itself but was left with the smaller warning above the clocks with a spanner and the word  Adblue. This disappeared after 2-3 miles. So, an intermittent error message. 

If you get this do check state of battery charge. Low battery caused the error on mine, hence why it disappeared after 2/3 miles of driving. Put the battery on a trickle charge for a few hours and guess what - no faults shown.

I’d hate to think that a dealer would change parts and charge the customer when all that was needed was a fully charged battery…

 

Colin

Hi Colin

I read your post with interest.

I own a 2020 S4 tdi which I’ve had since new, and has always been serviced by the main dealer. The warranty expired in March and it recently hit 60k miles. It’s been trouble free until 60k miles but since then it has been plagued with issues and all sorts of warning lights have been popping up, including an Ad blue system failure, gear box malfunction and drive system fault, as well as a squealing noise coming from the engine bay on start up- this is sporadic. The first issue to appear was the squealing noise and the other issues have followed.  The faults generally clear once the vehicle is restarted and don’t happen at all when I disable the start stop system.  It was in Audi for a diagnostic on Tuesday and I had a slightly confusing update from the dealer today.. the gear box needs to be replaced (planetary failure!) but this will be covered under goodwill (£11k!) but I’d have to pay the labour costs. However, they then said they could just clear the fault and I could see how it goes- earlier in the week they told me it wasn’t driveable..

Regarding the other issues, there is a fault with the alternator and this needs replacing (£1900) and apparently there is an ECU issue with the ad blue system- £2200 to sort.  I’m wondering if the gearbox and ad blue warning lights are just computer glitches caused by a low battery as a result of the alternator fault?

[colinmf]

Odd. My reply has not appeared.

In short, the Adblue error returned but I will charge the battery again tomorrow and see what happens. I have a service booked for next Wednesday which I'm getting nervous about; especially after seeing your post. The faults and costs on your car are not something I'd enjoy.

I have a code reader coming on Saturday so at least I stand a chance of going to the dealer with a little knowledge. My previous experiences have taught me not to trust dealers.

If anything of interest occurs I'll post again. 

[FarmerJon]

My 65 plate A4 2.0tdi Avant currently with an Audi specialist awaiting a new AdBlue tank, pump and ECU at a cost north of 2K 🙄 

This will be the second time this has happened, once at 65k back in 2019 and again now at 106k. 
 

love the car but certain that Audi know about this issue and are reluctant to acknowledge the fact. 
 

my dilemma is, do I keep the car once repaired or will other issues follow?