A bit of 955 ECU / electronics info + reset your cluster with VCDS!
02-24-2016, 12:25 AM
#1
AutoX
Thread Starter
Join Date: Dec 2015
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
A bit of 955 ECU / electronics info + reset your cluster with VCDS!
Hi all,
I've been working on an Android app to help with common service tasks on 955s. ( https://rennlist.com/forums/porsche-...sion-temp.html ). I've got a new version in the works, but figured I'd share my learnings here ahead of time for the impatient and curious:
1) The Cayenne's electronics are overall very, very similar to those in the Touareg and Phaeton, but half of the K-line modules are on pin 3 of the OBD port instead of the standard pin 7. By wiring pins 3 and 7 together (here's a diagram of the pin numbers, looking at the car's connector: http://www.obdtester.com/images/obd2_connector.png ), all of the standard VAG service tools including the shareware VCDS Lite are happy to connect up to the Cayenne.
2) The instrument cluster "Service Now" indicator is reset by setting the KOMBI (Instrument Cluster)'s Adaptation Channel 2 to value 0. And, if you're interested, Channels 40 and 41 are "km since service" and "days since service" respectively. You can do this through Durametric or by buying and registering the shareware version of VCDS-Lite and purchasing a cheap knockoff VAG-KKL cable to go with it. Eventually I plan to add this capability to my Android app!
I've been working on an Android app to help with common service tasks on 955s. ( https://rennlist.com/forums/porsche-...sion-temp.html ). I've got a new version in the works, but figured I'd share my learnings here ahead of time for the impatient and curious:
1) The Cayenne's electronics are overall very, very similar to those in the Touareg and Phaeton, but half of the K-line modules are on pin 3 of the OBD port instead of the standard pin 7. By wiring pins 3 and 7 together (here's a diagram of the pin numbers, looking at the car's connector: http://www.obdtester.com/images/obd2_connector.png ), all of the standard VAG service tools including the shareware VCDS Lite are happy to connect up to the Cayenne.
2) The instrument cluster "Service Now" indicator is reset by setting the KOMBI (Instrument Cluster)'s Adaptation Channel 2 to value 0. And, if you're interested, Channels 40 and 41 are "km since service" and "days since service" respectively. You can do this through Durametric or by buying and registering the shareware version of VCDS-Lite and purchasing a cheap knockoff VAG-KKL cable to go with it. Eventually I plan to add this capability to my Android app!
02-25-2016, 01:26 AM
#5
AutoX
Thread Starter
Join Date: Dec 2015
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
My full source code is up on GitHub in the project linked from the other post: https://github.com/bri3d/kwp-android-logger (don't judge me too harshly - it's my first Android app ever!)
Not much to it - the Cayenne talks (like most VW vehicles) via a pretty bog-standard protocol: ISO14230 KWP2000. In the case of the 955, it's even old enough that it uses the entire ISO14230 stack from the bottom up. Newer cars use the same ISO14230 commands, but over a different system like TP2.0 or UDS over CANbus. At any rate, the documentation is readily available online and as an ISO standard, it's generally quite accurate.
Once I discovered the pin3 + pin7 trick, everything pretty much solved itself. I just read the ISO14230 documentation available from various sources and implemented to the specification. Again, if you use VCDS-Lite or even old VAG-COM from before the software was rebranded, it'll work fine with the Cayenne's control modules provided it can find all of them.
As an illustration of some of the work I did, the transmission temperature was easy: I applied VW measurement block conversions (well documented online) to the data returned by the ISO14230 ReadLocalIdentifier method. Then, I iterated through each measurement block and looked at each value with the "deg C" conversion applied to it. I found which one matched the measurements from an IR gun. Done.
Fault codes are the same way: there's a standard KWP2000 request for fault codes and fault code reset, and sure enough, they worked with each module once I was able to connect up.
Adaptation is a little more complex and doesn't seem to be well documented online. I had to make a bit of a compendium of various systems. It isn't in the released version of my app yet but I'm working on getting it all put together. I mostly pieced together the mechanism by treating the factory software like a black box, logging various requests, and going from there.
A lot of the issues I've had have been with poorly made "ELM327" chips. The "ELM327" is really just a software for PIC microcontrollers, and probably 95+% of the "ELM327" devices in existence aren't truly ELM327s made by the original manufacturer but rather other PIC chips programmed with various counterfeit software that works with the same command set. Some of it works flawlessly but a lot of it is straight-up trash, for example one of the ELM327 "V1.5" units I've found doesn't understand any of the ISO14230 / KWP2000 physical protocol methods implemented in... version 1.2
Not much to it - the Cayenne talks (like most VW vehicles) via a pretty bog-standard protocol: ISO14230 KWP2000. In the case of the 955, it's even old enough that it uses the entire ISO14230 stack from the bottom up. Newer cars use the same ISO14230 commands, but over a different system like TP2.0 or UDS over CANbus. At any rate, the documentation is readily available online and as an ISO standard, it's generally quite accurate.
Once I discovered the pin3 + pin7 trick, everything pretty much solved itself. I just read the ISO14230 documentation available from various sources and implemented to the specification. Again, if you use VCDS-Lite or even old VAG-COM from before the software was rebranded, it'll work fine with the Cayenne's control modules provided it can find all of them.
As an illustration of some of the work I did, the transmission temperature was easy: I applied VW measurement block conversions (well documented online) to the data returned by the ISO14230 ReadLocalIdentifier method. Then, I iterated through each measurement block and looked at each value with the "deg C" conversion applied to it. I found which one matched the measurements from an IR gun. Done.
Fault codes are the same way: there's a standard KWP2000 request for fault codes and fault code reset, and sure enough, they worked with each module once I was able to connect up.
Adaptation is a little more complex and doesn't seem to be well documented online. I had to make a bit of a compendium of various systems. It isn't in the released version of my app yet but I'm working on getting it all put together. I mostly pieced together the mechanism by treating the factory software like a black box, logging various requests, and going from there.
A lot of the issues I've had have been with poorly made "ELM327" chips. The "ELM327" is really just a software for PIC microcontrollers, and probably 95+% of the "ELM327" devices in existence aren't truly ELM327s made by the original manufacturer but rather other PIC chips programmed with various counterfeit software that works with the same command set. Some of it works flawlessly but a lot of it is straight-up trash, for example one of the ELM327 "V1.5" units I've found doesn't understand any of the ISO14230 / KWP2000 physical protocol methods implemented in... version 1.2
04-12-2019, 10:14 AM
#7
2nd Gear
Join Date: Apr 2019
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Hi all,
I've been working on an Android app to help with common service tasks on 955s. ( https://rennlist.com/forums/porsche-...sion-temp.html ). I've got a new version in the works, but figured I'd share my learnings here ahead of time for the impatient and curious:
1) The Cayenne's electronics are overall very, very similar to those in the Touareg and Phaeton, but half of the K-line modules are on pin 3 of the OBD port instead of the standard pin 7. By wiring pins 3 and 7 together (here's a diagram of the pin numbers, looking at the car's connector: http://www.obdtester.com/images/obd2_connector.png ), all of the standard VAG service tools including the shareware VCDS Lite are happy to connect up to the Cayenne.
2) The instrument cluster "Service Now" indicator is reset by setting the KOMBI (Instrument Cluster)'s Adaptation Channel 2 to value 0. And, if you're interested, Channels 40 and 41 are "km since service" and "days since service" respectively. You can do this through Durametric or by buying and registering the shareware version of VCDS-Lite and purchasing a cheap knockoff VAG-KKL cable to go with it. Eventually I plan to add this capability to my Android app!
I've been working on an Android app to help with common service tasks on 955s. ( https://rennlist.com/forums/porsche-...sion-temp.html ). I've got a new version in the works, but figured I'd share my learnings here ahead of time for the impatient and curious:
1) The Cayenne's electronics are overall very, very similar to those in the Touareg and Phaeton, but half of the K-line modules are on pin 3 of the OBD port instead of the standard pin 7. By wiring pins 3 and 7 together (here's a diagram of the pin numbers, looking at the car's connector: http://www.obdtester.com/images/obd2_connector.png ), all of the standard VAG service tools including the shareware VCDS Lite are happy to connect up to the Cayenne.
2) The instrument cluster "Service Now" indicator is reset by setting the KOMBI (Instrument Cluster)'s Adaptation Channel 2 to value 0. And, if you're interested, Channels 40 and 41 are "km since service" and "days since service" respectively. You can do this through Durametric or by buying and registering the shareware version of VCDS-Lite and purchasing a cheap knockoff VAG-KKL cable to go with it. Eventually I plan to add this capability to my Android app!
Trending Topics
07-24-2023, 10:47 AM
#11
Burning Brakes
Thanks for this bri3d, recenly aquired an 05 V6 and after servicing it myself needed to reset the service indication . I have an old genuine VCDS lead (2009 ish) and bought an obd extension off ebay crossed wires 3 and 15 in the extension and was able to access the instrument cluster and reset with adaption channel 2 - Thanks!
Tony
Tony