Audi Q7 4L Climatronic long coding research

There are no labels for LongCoding in module J255 - Climatronic for Audi Q7 4L. Let's try to figure it out.

Known car

Here's and original coding from a car that I have available: 01 04 80 18.

It's a 2014 Audi Q7 4L, facelift, 4-zone climate control, 4.2TDI 8-cylinder engine, LHD, EU spec.

Data from other cars

Browsing through the internet forums I found couple VCDS scans which should be helpfull.

01 00 94 16 - someone on YT           Q7, d?????, 6???, RHD
01 00 9C 16 - someone on elektroda    Q7, diesel, 6cyl, RHD
01 00 94 16 - VCDS UK                 Q7, diesel, 6cyl, RHD
01 01 35 12 - VCDS UK                 Q7, diesel, 6cyl, RHD
01 04 94 16 - VCDS UK                 Q7, diesel, 6cyl, RHD
01 00 9C 16 - VCDS UK                 Q7, diesel, 6cyl, RHD
01 00 94 16 - VCDS UK                 Q7, diesel, 6cyl, RHD
01 00 84 58 - VCDS New Zealand        Q7, diesel, 8cyl, LHD
01 04 80 18 - Tata                    Q7, diesel, 8cyl, LHD
01 00 90 16 - forum VCDS Finlandia    Q7, diesel, 6cyl, LHD
01 00 98 16 - VCDS Iceland            Q7, diesel, 6cyl, LHD
03 04 A0 36 - forum VCDS USA          Q7, diesel, 6cyl, LHD
03 04 A0 36 - forum VCDS USA          Q7, diesel, 6cyl, LHD
03 02 A0 36 - VCDS USA                Q7, diesel, 6cyl, LHD
03 04 A0 36 - VCDS USA                Q7, diesel, 6cyl, LHD
00 04 A0 36 - VCDS USA                Q7, diesel, 6cyl, LHD
00 0C C0 26 - VCDS USA                Q7, petrol, 6cyl, LHD
00 08 C0 46 - VCDS USA                Q7, petrol, 6cyl, LHD
00 0C C0 26 - VCDS USA                Q7, petrol, 6cyl, LHD

Looking for pattern

Diesel vs Petrol

It looks like all diesel cars have Byte 03 → bit 4 set to 1.

Cylinder count

With bunch of 6 and 8 cylinder engines, we can clearly see that Byte 3 → bit 0-3 stores the cylinder count.

Region

Looks like there's some corelation between Byte 00 → bits 0-3 and region. It might be the whole Byte 00 - who knows.

LHD/RHD

Some cars were from UK, which means those are most likely to be coded for RHD config. Climatronic needs this to know which control knob is for driver.

We have a good candidate for this config - Byte 02 → bit 2. Looks like RHD vehicles will have this bit enabled.

Webasto / Aux Heater

I know that the Webasto Parking/Aux heater/ventilation controls for MMI can be coded in Byte 02 → bit 3.

Summary

Byte 00 → bits 0-7 → Region (00=?; 01=Europe; 03=USA)
Byte 02 → bit 2 → LHD/RHD
Byte 02 → bit 3 → Aux Heat./Vent. controls on MMI
Byte 03 → bits 0-3 → cylinder count
Byte 03 → bit 4 → isDiesel