Appologies if you know this already.

In order to confirm the integrity of the code in the ROMs (i.e. that they haven't failed or been inadvertantly changed) the system performs a calculation using the value at every memory location. This is often called a checksum; although some are more complex than simply adding all the values together and lookng at the remainder. The upshot of this is that if you change some of the data within the ROM (adaption, coding, tuning etc.) you must also calculate correctly what the new checksum will be and change that too. The inference from the comments in the linked thread is that your ROM has been modified with a tool that got the checksum wrong. Fortunately the ECU still seems to operate with an incorrect checksum so you could ignore it.

Clearing the fault will not work because the checksum error is still there. You might be able to clear it by writing some new data to the ROM and hoping that your tool will re-calculate the checksum from scratch and get it right. Completely re-loading the ROM should cure it but this is brown trouser stuff if you do't know what you are doing and you would need to get hold of the correct ROM image.

A remote possibility is that you really do have a ROM fault e.g. a bit stuck at 1 or 0. In this case a replacement ECU would be the likely solution.

 

HinJohn

Thanks for the reply, I sort of understand it....

So I guess we are talking the main (are their any others?) ECU?

I have a feeling that there may be an alarm fault, possibly battery, I need to check this out, but other than that I believe all is good, I am hoping this is not related.

The car drives and performs fine, from memory there was also a canbus fault and possibly something to do with the comfort settings.

I hope to purchase a code reader (in research stage at the moment) to gain a better knowledge of these faults.

Re-Reading the fault code on the picture is it suggesting that the fault code actually is immobiliser related?

 

You haven't already, you can read up on the alarm issue here. I think we'll be seeing more and more of these errors across the Forum as our Mk2's continue to get older and older -

https://www.ttforum.co.uk/forum/viewtop ... &t=1836515

Just for grins, I found this posted in another forum. Seems fitting since you're delving into VCDS codes. [smiley=computer.gif]

Yesterday, I had a scare,
I saw a code that wasn't there.
But it was there again today,
I wish, I wish it'd go away...

The original 'Antigonish' poem is by William Hughes Mearns -

Yesterday, upon the stair,
I met a man who wasn't there.
He wasn't there again today,
I wish, I wish he'd go away...

 

You might check the primary address and see if there's a way you can reset it. I say that based on my recent finding of how to reset the brake pad warning light in this YouTube video. Not sure if you can do this with an OBD-11...???

 

Good news!

Alarm is fine! Yahey!

 

@happychappy did you have this fixed or just ignored it? I have the same issue, there seems to be absolutely zero effect on how the car works, just shows up on scan:

Address 25: Immobilizer Labels: 1K0-920-xxx-25.clb
Part No SW: 8J0 920 930 E HW: 8J0 920 930 E
Component: KOMBIINSTR. VDO H23 0150
Revision: D0H23003 Serial number: AUX7Z0H1FNJ0YP
Shop #: WSC 00000 000 00000
VCID: 2E5305C3B9FD45E669-807A

1 Fault Found:
16346 - Control Module - ROM Error
014 - Defective

 

Hiya

To update it did turn out to be an alarm fault, I hadn’t manually checked it correctly, so I changed the alarm module inside the wing and all was ok.

However, I am now due another module change as it’s failed again.

 

 

Yea, seen that. That's in the top ten of least helpful Ross Tech pages.

Edit: my error may be related to the fact I apparently have a replaced/flashed tranny.

 

Yea, seen that. That's in the top ten of least helpful Ross Tech pages.

LOL yeah some of the pages are like that. I suppose at least it's better than no page at all (which happens a lot of the time too) but the ol' beggars can't be choosers also applies--it's free information online and all.

Edit: my error may be related to the fact I apparently have a replaced/flashed tranny.

Might well be. Seems like possible immo mismatch between the TCU and cluster? But odd everything works fine if that's the case. No other errors? Usually you'd think you'd get the "control module incorrectly coded" type of error but TBH my guess is as good as yours (and RT's lol).

The more frightful thing about it though is, what if it's a sign of impeding failure of the cluster? 😳 They're known to be problematic/fail, so that's a possibility too.

When the transmission was replaced and TCU flashed and all that, was there anything done for the immobiliser/cluster as well?

 

There are zero fault codes other than the alarm/immo and the broken driver side door lock which has a broken "open" motor. Everything works just fine.

I have no idea of what's been done to this TT other than regular services, but I do know it's a salvage title. The frame and body panels are in perfect order, so whatever happened to it (in its first year as per Carfax), it's been fixed good.

I have not yet had the time to dig in deep with the inner workings of an Audi of this age and configuration, but generally it is not uncommon to have proxy alignment issues when an ECU is replaced. IIRC (I have the worst memory, scanned all the ECUs today) transmission control unit shows ~65 000km on it, and the gauge cluster shows 148 426km, which pretty well matches the overall wear and tear of the car (steering wheel, seats, shifter, all the knobs, interior lining, underside, timing chain). So I have absolutely no doubt the car has ~150000km on it, and it seems the tranny had something done to it about 65 000km ago.

The Immo is functional, and communicates with the rest of the system. So it's not like it has been defunct deliberately. There is a fault with the ROM, but it does not prevent it from allowing star.

P.S. Carfax history supports the shown mileage also: it accumulates very linearily, up until the last years here in finland, where it has been a "hobby car" so to say, with less annual driving than before.

 

I refer you to post #2 in this thread. Checksum error as a result of software packages being used to change things in the instrument cluster is the most likely cause. I've had a "ROM error" ever since someone reprogrammed new keys to my car for me.

A few of us are fortunate enough to have owned our cars from new but most of us have to take them on with up to 20 years of other folks messing. Like any partnership you'll never know it all so carpe diem.

 

Not scanned the car recently, but pretty sure the alarm is knackered again.

Yes, was a secondhand unit purchased last time.