Canbus decoder - 996 C4S 2002

Dcl1604 · May 19, 2020

Canbus decoder - 996 C4S 2002
Hi, has anyone had any success with any CANBUS decoders for a 996? I'm trying to replace the factory CDR23 MOST radio with a double DIN kenwood nav unit, and i'm really struggling with the CANBUS. I've tried 3 different decoders now, 2 from connects2 (STK445 & STK551 - one is for a 997 & one for a Cayenne) and a Dietz 66030, but no joy with any of them.. I need the canbus decoder to give me the switched live, Illumination, Reverse, and handbrake signals for the new headunit without having to hardwire everything or hack/cut/splice anything on the vehicle harness, it should in theory simply connect to the permant live & canbus high/low from the factory radio harness, and provide these outputs.. I've tried getting help from Connects2, but they just recommend to take a switched live from elsewhere & do without the rest...
The rest of the Connects 2 stuff seems to do the job, the MOST decoder works OK taking the RCA feed from the new headunit & retaining the factory amp & speakers, but the CANBUS stuff has beaten me...
If anyone has managed to get a canbus decoder to work, i'd be really interested to know which one.. Thanks in advance for any help you can offer.

Richard_Hamilton · May 19, 2020

Welcome David!

I'm guessing that if your car has the MOST bus, it is MY2003. Check 10th digit of the VIN. (2=2002, 2=2003).

I think you'll find that the available CAN signals are a lot less comprehensive than in the 997 and later Cayennes, which have a separate CAN controller. The Comfort CAN controller in the 996 is incorporated in the instrument cluster. Basically, it only communicates between the cluster, radio, and air conditioning. You might get the signals from the Drive CAN, but it would still mean wiring into the Drive CAN somewhere other than the radio.

There is no switched supply at the black radio plug, but there is a speed signal (grey/pink wire) and backup signal (black/blue). For the handbrake signal you have to connect to the handbrake switch itself, and you can take a switched live from one of the orange wires on a bridge plug on the back of the relay panel, or at the fuse box.

Dcl1604 · May 19, 2020

Thanks Richard, yes it is a MY03 car.

You mention a backup wire - is that the same as the reverse signal? i.e. +12v signal in reverse?

Thanks again

Richard_Hamilton · May 19, 2020

Yes, it is the reversing signal. It is just marked backup signal on the wiring diagram. I assume it goes live when reverse is selected. It should be easy enough to test.

Laurence Gibbs · Mar 21, 2024

This post is most useful but a question to Richard or anyone who can explain. Pcm 2 on my 04 booster has a can connection . The A plug has No switched live the position pin 7 isn't populated. So how does my pcm switch on if not via can comfort lines? I am running into the same issue as the op in so much as the decoder I have for my android auto unit doesn't seem to power on the unit. It must be possible if pcm2 does it? Can someone shed light on how else my pcm2 is turning on without a switched live at pin 7 of plug A ???

Laurence Gibbs · Mar 21, 2024

Thought it worth adding , if I run a switched live it all works fine and I think some of the can functions do work , specifically switch off on door open which I think is can controlled ? I am leaning on the thought that the can protocol script doesn't work quite right ? The file it's using says Cayenne rb58 or something similar. I wonder if the 996 script/ protocol is different ?

Laurence Gibbs · Mar 28, 2024

Okay still looking for answers to does anyone have a working van bus decoder for 9x6 android head unit?
I've done some more playing around and my original protocol is BG Cayenne BG.XP when using the protocol print function in the factory settings menu I get a single line of what looks like rubbish. However if I change the settings to RZC (raise) PQ Low and view the protocol print on screen I get scrolling lines of what might be useful can data . My thoughts are that I still don't have a working protocol for the decoder . I wonder if anyone has the decoder files for a working pccm plus ?

Laurence Gibbs · Apr 10, 2024

So further to my rambling. My decoder box is marked can bus decoder Porsche . Despite this these boxes are fairly universal and how they work is dependent on the protocol they are loaded with. My box doesn't work with my 986 but the box itself is not at fault . If I use a VW can bus id for ignition key on 0x271 and feed it the correct can data I can get the box to operate it's 12v switched live feed . Obviously the can id for ignition key on for the 986 is not 0x271 . I would guess you can try as many boxes as you like but if they aren't loaded with the correct protocol to translate the 986 / 996 can id's you won't get anywhere .

Damo911996 · Apr 17, 2024

I think its best to hard wire. this is the 996.2 canbus info supplied by 911uk member that i got hold of for another project.

Address 0x4E0
Oil temp, start bit 40, length 8, intel byte order, unsigned, factor 0.75, offset -48 (-48 to 142.5 degrees C)

Address 0x298
Intel air temp, start bit 8, length 8, intel, unsigned, factor 0.75, offset -48

Address 0x520
Oil pressure, start bit 32, length 8, Motorola unsigned, factor 0.04,

bar Ambient temperature, start bit 24, length 8, intel unsigned, factor 0.5, offset -40

Address 0x280
Throttle position, start bit 40, length 8, intel, unsigned, factor 0.390625

Engine speed, start bit 16, length 16, intel, unsigned, factor 0.25, RPM

Address 0x289
Coolant temp, start bit 8, length 8, intel, unsigned, factor 0.75, offset -48

Address 0xC0
Steering angle, start bit 4, length 12, Intel byte order, signed, factor 0.390625

Address 0x2A8
Wheel speeds, all length 15, intel, unsigned, factor 0.01, km/h

FL start bit 1
FR start bit 17
RL start bit 33
RR start bit 49

Address 0x1A0
ABD intervention, start bit 3, length 1, intel
TCS intervention, start bit 0, length 1, intel
TCS intervention (fast), start bit 40, length 8, Motorola unsigned, factor 0.39, %
TCS intervention (slow), start bit 32, length 8, Motorola unsigned, factor 0.39, %
ABS intervention, start bit 2, length 1, intel.

Laurence Gibbs · Apr 18, 2024

Yep,
i'd be inclined to agree it's easiest to just hard wire it and that's what i've ended up doing . shame that a firmware update for the decoder box doesn't seem to exist. PCCMplus must have one ?
The can id's you have are for the drive can bus , though some overlap must occur it's the comfort can bus that handles the Radio , aircon and gauge cluster. Hopefully attached is a list of can id's for the comfort can can bus on my 04 boxster S. The important i'd as far as i've found is at address 0x000, this is the id for the ignition switch and lights on . it's it's 3 bytes long and when the key is inserted the first byte goes from 00 to 01 and when ignition is on it goes from 01 to 03 . The second byte is lights on and goes from 00 to 64 . With time it would be possible to work out all the other id's.
ID DLC Data Period Count Comment
000 3 01 00 00 100 1108
101 8 00 00 00 00 00 00 00 2F 102 1107
103 8 00 E0 00 E0 00 20 00 A0 102 1107
105 8 00 00 60 00 42 00 80 00 103 1107
107 6 01 00 80 00 00 00 999 111
111 2 C0 00 100 1106
2C1 4 00 20 26 55 1004 111
301 6 01 00 53 71 71 16 1000 111
303 8 80 72 00 30 12 78 65 CD 104 1107
304 5 34 53 46 60 76 999 111
305 6 00 00 00 00 00 00 1000 111
306 5 17 3A 35 98 0A 1000 111
316 6 1F 3F 3F 7F 0F 1F 830 60
400 4 01 02 02 FF 276 407
401 4 02 12 02 FF 280 407
402 4 00 12 02 FF 261 407
580 8 05 00 19 01 00 81 00 00 498 16
608 8 A3 00 00 00 00 00 00 00 999 387
618 8 A1 01 00 00 00 00 00 00 1000 387

in the table above id 0x000 shows key in ignition but not on and no lights 0x000 3 03 64 00 would be ignition on lights on. I never tried an engine running log.