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View Full Version : Coolant temperature gauge linearization and other cluster EEPROM mods



Mad Cow
05-05-2015, 12:26 PM
I've been playing with my cluster EEPROM the past few days and figured I might as well post my progress here, thanks to some very helpful souls in this thread (http://nefariousmotorsports.com/forum/index.php?topic=7964.0) on Nefmoto I've been able to linearize the temperature gauge (stock it stays in the middle between 80 and 100 degrees and is way inaccurate below 90). There are a couple other things you can mess with such as the volume and frequency of the buzzer, the temperature range for the icy road warning, and what gets illuminated when you turn the key on. You can also adjust the speedo so that it displays a more accurate value since these things always read slightly higher than your actual speed. Finally, you can calibrate your speedo and tach if for some reason you need to replace the gauge faces with ones that have a different scale.

To read the EEPROM you can use VAG EEPROM Programmer (http://autosoftos.com/soft-i-po-lekarstvo/190-vag-eeprom-programmer-v119-skachat.html) with a standard blue KKL cable. Just pick your cable's COM port and go to Dash --> Read EEPROM, then save the file wherever. To linearize the temp gauge open the file in your favourite hex editor (I like HxD (http://mh-nexus.de/en/hxd/)), search for the values:
F0 00 E0 01 80 02 20 03 D0 03 10 04 00 00 00 00 C7 02 C7 02 B0 04 8C 05
and replace that with:
00 00 40 01 E0 01 80 02 20 03 C0 03 00 00 00 00 28 00 E1 01 C1 03 A1 05 In my bin this is located at 0x13F, should be in the same spot or very close for other cluster part numbers. And that's it, your temperature gauge will now tell you exactly what your coolant temp is.

Next step is trying to figure out what controls illumination with key on, you can set it to light just the gauges, screen, or needles, or any combination of the three. I'm also looking into the oil temp gauge to see if it needs linearization too.

Note that this seems to only apply to 00+ clusters since every EEPROM dump from earlier years I've seen is a quarter of the size, there might still be hope but I'll have to look into it more.

Murph_129
05-05-2015, 01:43 PM
Neat! [up]

k0mpresd
05-05-2015, 11:28 PM
good to see you sorted this. [up]

Mad Cow
05-06-2015, 04:53 AM
good to see you sorted this. [up]
Yep turns out it was easier than I thought it would be. Have you tried messing with the lighting control byte before? Either I'm doing something wrong or the default value is different from mk4 clusters.

k0mpresd
05-06-2015, 05:01 AM
never messed with it. someone else asked about it not too long as well. i know in the mk4 clusters its in a different spot based upon usa vs euro firmware.

Mad Cow
05-07-2015, 07:53 AM
never messed with it. someone else asked about it not too long as well. i know in the mk4 clusters its in a different spot based upon usa vs euro firmware.

Yea that's what I've read too, one of them has a default value of 30 and the other is 70. I just realized I'd been understanding it all wrong though, got a few more potential locations I can check now. If I understand correctly MK4's don't light up the clock and odometer displays with the key on, never paid close enough attention to confirm whenever I saw one in person. I was assuming they worked like B5s that do light up those displays.

mysman
05-07-2015, 08:34 AM
I'm using the discontinued Ross-Tech KEY-COM presently; any idea if this cable will work for the VAG EEPROM programmer? Would be better to "upgrade" to a newer cable like KII-USB? I'm AEB/ME5 and would like to take a look at this linearization. Thanks.

Mad Cow
05-07-2015, 09:12 AM
I'm using the discontinued Ross-Tech KEY-COM presently; any idea if this cable will work for the VAG EEPROM programmer? Would be better to "upgrade" to a newer cable like KII-USB? I'm AEB/ME5 and would like to take a look at this linearization. Thanks.

I'm not sure what chipset the KEY-COM uses, but it should work since VAG EEPROM Programmer works with buth virtual COM ports and direct USB. However the older clusters don't support these kinds of changes from what I know, I'll have to look into it more but the prospects aren't great since there just isn't enough space on the EEPROM chip to hold all these maps.

On the plus side, I did find the lighting byte at 0x1DE. Bad news is it only has 2 modes: stock (just displays), and everything lit up. The default value is 35, a value of 30-37 gives you the stock mode and any value 38-3F lights up everything. I was hoping to light up just the needles like the MK4 guys can do but I guess it's just not possible.

MetalMan
05-07-2015, 09:20 AM
This is pretty neat, will definitely be following it!

So since you're in there (and I'll admit I didn't read the Nefmoto thread), is there any chance of programming in a needle sweep at engine start? (or just key-on)
I know these clusters can sort of do a needle sweep during the appropriate Output Test.

Mad Cow
05-07-2015, 10:17 AM
This is pretty neat, will definitely be following it!

So since you're in there (and I'll admit I didn't read the Nefmoto thread), is there any chance of programming in a needle sweep at engine start? (or just key-on)
I know these clusters can sort of do a needle sweep during the appropriate Output Test.

You can't do that through the EEPROM unless there's a hidden byte somewhere that enables it. All the EEPROM does is store data, mostly gauges maps, some config bytes, IMMO/part number info, mileage reading, coding, things like that. You'd have to read off the microcontroller binary and disassemble it to figure out a gauge sweep, which is about as far over my head as the average airplane. I don't even know what microcontroller it uses.

walky_talky20
05-09-2015, 06:11 AM
^It sounds like your *at least* in the air traffic control tower. The rest of us are still on the ground. ;)

Nice work, this is interesting stuff. Another item, if you're taking requests: removing some of the "dampening" of the outside temp sensor value.

Mawhitey
05-20-2015, 02:55 PM
Id like my immo light turned off, save me ripping it to bits and applying tape to the LED

Iv'e changed to ME7.5 and it won't adapt with my dash/keys. Euro cars suck

walky_talky20
05-21-2015, 08:10 PM
It is my firm belief that dealers should be required by law to perform an immobilizer defeat at any point in the car's lifetime on request of the owner, provided there is proof of ownership. And do so for a nominal fee.

$300 keys and dealer-only coding of modules doesn't make sense once the car is 15 years old. You should be able to unlock it if you want.