how toreset CAN BUS?

[Guest]

I know it has been written before, but it seems I cant find it.

could someone explain how to reset the CAN bus?

thanks.

Edited November 13, 2009 by stealthTT

[Guest]

I really need to know which fuse I have to unplug.

thanks.

[Loren]

CAN is in several control modules - I think you will need to disconnect the battery then reconnect it a few minutes later.

[wvicary]

Maybe you could explain what you are trying to do or the problems you are having. Are you trying to wake up the CAN?

[Guest]

had been busy with other things lately, thanks for help and sorry for not answering. I will sure need more further assistance.

a short story:

I've changed the battery, from the driver seat. prior changing it had some issues, like some PSM warnings, driver presets memory lost, and other. I have assumed that it all came from the battery, and I was right. Changed the battery, and all problems were gone :)

Then, after a week or so some problems occured, and the main one that I dont like is malfunction(or stoped worked) some Main Cluster instruments. and I have:

- ODOMETER - stopped working; It showes the older values but doesnt record the new ones(i've put on the car since then close to 350 miles and nothing), it just stopped.

- Info Display - the upper part - doesnt work, sometimes it shows the radio infos for like 1-2 seconds, and then disapears

- Outside Temperature sensor - doesnt work. on the PCM it shows no values.

- The GASOLINE(FUEL) LEVEL GAUGE - doesnt work, its dead.

Now, I've runned Durametric and I don't have even an error on the main cluster, but cammed out with other issues and thanks to Loren I'm getting closer but not that close as I whished.

P0074 Ambient Air Temperature Sensor No signal / Communication Present

P0074 Ambient Air Temperature Sensor Circuit Intermittent

Possible cause of fault

- Fault in instrument cluster

1314 DME control module No signal / Communication

1299 Gateway No signal / Communication Present

and Loren suggested a comunication problem on the CAN network.

thats why I thought about to reset the CAN network, thought it would help a bit or not.

also, thanks to Loren I have found that thread:

From the Durametirc manual:

"Cannot connect to 2005 – 2006 Cayenne

If the instrument cluster says “press brake pedal” this means the CAN network is asleep and you need to wake up the network by pressing the brake pedal.

The CAN gateway may need to be reset. If VAG-Com has been used on this car it is likely that the CAN gateway will need to be reset. To reset the CAN gateway take the key out of the ignition and remove fuse #40 for at least 10 seconds. The fuse panel is on the left side of the dashboard where the dashboard meets the door panel."

I will try that, but I I'll apreciate your further help as well. also, can someone suggest whats up with the others problems like the DME module and Gateway? I keep having these issues from time to time and dont know what it means nor what to do.

thanks a lot for your support.

Ilie.

Edited November 28, 2009 by stealthTT

[wvicary]

It's best to have the vehicle running or a battery charger in use when accessing faults on the Cayenne, they are very sensitive to voltage drops and can cause false codes as the vehicle has very high parasitic draws. Also recommended to have your laptop connected to the AC adaptor.

You first need to access every control module your Cayenne has and clear all the fault codes. Do this after you have performed the CAN reset. Drive the vehicle for a few miles then re-scan all module for fault codes. See if this clears up any faults and report back to us.

I think you have a connection problem in the instrument cluster that will require more investigation.

[Guest]

It's best to have the vehicle running or a battery charger in use when accessing faults on the Cayenne, they are very sensitive to voltage drops and can cause false codes as the vehicle has very high parasitic draws. Also recommended to have your laptop connected to the AC adaptor.

You first need to access every control module your Cayenne has and clear all the fault codes. Do this after you have performed the CAN reset. Drive the vehicle for a few miles then re-scan all module for fault codes. See if this clears up any faults and report back to us.

I think you have a connection problem in the instrument cluster that will require more investigation.

just like computers, sometimes it needs a refresh :)

And it worked!!!

I've followed the instructions from Lauren post, removed the #40 fuse for more than 10sec, and everything started to worked again, flawless :).

The software didn't seen an error on instrument cluster because of a comunication error, I supposed.

I'm glad that I didn't had to invest some more money into this car, again.

I'll run the Durametric on the car and see what I get.

thanks ,

ilie