Seeking OBD enlightenment

[hoolieman]

The following codes are lurking in the background of my beloved 2.0L diesel A4.:

P200200 PARTICULATE TRAP BELOW THRESHOLD

P204B00 REDUCTANT PRESSURE SENSOR CIRCUIT RANGE

P204F0ON REDUCTANT SYSTEM PERFORMANCE BANK1

The car currently drives well, although I'll begin to feel the pinch if the cost of AdBlue increases.

Could someone give me an idea of what I might have to do to prevent catastrophe?

Many thanks in advance.

[Stevey Y]

58 minutes ago, hoolieman said:

The following codes are lurking in the background of my beloved 2.0L diesel A4.:

P200200 PARTICULATE TRAP BELOW THRESHOLD

P204B00 REDUCTANT PRESSURE SENSOR CIRCUIT RANGE

P204F0ON REDUCTANT SYSTEM PERFORMANCE BANK1

The car currently drives well, although I'll begin to feel the pinch if the cost of AdBlue increases.

Could someone give me an idea of what I might have to do to prevent catastrophe?

Many thanks in advance.

Hi Jim what diagnostic platform are you using?, try deleting the two codes for the reductant and see if they come back, the code I would be more alarmed about is p2002 thats a nasty one, its not that the DPF is blocked, thats still working, no its the low pressure EGR cooler, this is well documented on this forum and normally requires replacement I got through at least three of them in the time I owned my A6, the engines are common to the A4/A6 and due to the Ultra technology share the same emissions problems, the design is basically flawed as it takes gas for the DPF and burns it again problem is as it cools the gas through the cooler tubes the adblue crystals become solid again and block the tubes  and the valve mounted on the cooler filling them with a slimy white mess, adblue wont harm paintwork etc but when it comes in to contact with basic steel it will corrode it and rot the tubes out and then you end up with adblue crystals in the expansion tank and causing a white film on the tailpipes, if you do search there is ton of info on here with pictures.

Steve.

[hoolieman]

Thanks for your reply Steve.

The diagnostic platform's not mine but I think the reductant related codes will clear as the light comes on when AdBlue's low and then goes out a little while after re-filling.

As for the p2002, I'll look into it as you suggest and maybe I should get the DPF cleaned.

I'm hopeful that if it comes to it the EGR cooler would be covered under warranty.

 

[Stevey Y]

1 hour ago, hoolieman said:

Thanks for your reply Steve.

The diagnostic platform's not mine but I think the reductant related codes will clear as the light comes on when AdBlue's low and then goes out a little while after re-filling.

As for the p2002, I'll look into it as you suggest and maybe I should get the DPF cleaned.

I'm hopeful that if it comes to it the EGR cooler would be covered under warranty.

 

Hi I wish you luck with the warranty, its a hell of a job and requires significant stripping down as well as elastic arms and fingers to get it out, the easiest way is remove the front end and drag it out with the cat attached, I tried cleaning it in situ with every chemical known to man but ultimately it always needed replacing.

Steve.

[hoolieman]

Oh dear. I can safely say I won't be trying that myself.

Thanks for the heads up anyway Steve.