Author Topic: Protocol  (Read 5694 times)

Offline speedlever

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Protocol
« on: March 22, 2012, 09:41:14 AM »
I just got my UG EM yesterday. Thanks for the quick service!

I have two Hondas... a 2006 Pilot and a 2008 Ridgeline. I installed the UG in the RL and it discovered the 9141 protocol. I thought it would get the 29bit CAN protocol per page 12 of the user guide where it says most 2008 and newer Hondas use this.

Is it possible for a vehicle to be recognized as having more than one protocol? If so, should I try to force 29bit CAN?

I haven't tried it in the 2006 Pilot yet so I don't know what protocol it will discover there.


Offline UltraGauge Admin

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Re: Protocol
« Reply #1 on: March 22, 2012, 11:30:17 AM »
prior to 2008, many manufacturers supported two interfaces on the OBDII connector.  The old protocol and the new CAN protocol.  In general the CAN interface/protocol would not respond to general OBDII devices and was primarily there just for the the manufacturers use.   If your vehicle is a 2008 it was required by federal mandate to support CAN.....unless you have a vehicle that was not sold in the US.  If your vehicle was not sold in the USA, then you would need to check the requirements of country it was sold into.  UG tries the 9141 protocol last.  So if your vehicle supports CAN, it would have found it first. 

Offline speedlever

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Re: Protocol
« Reply #2 on: March 22, 2012, 01:15:11 PM »
The 2006-2008 and part of the 2009MY RL was built in Alliston, Canada and sold in the USA. In 2009MY, the RL production was moved to Alabama. Neither of which should have any impact on the CAN bus/protocol issue.

So I'm kind of stumped by this protocol issue. Could the fact that I have another OBDII device on the port cause the UG to default to the 9141 protocol and not the 29-bit CAN?


Offline UltraGauge Admin

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Re: Protocol
« Reply #3 on: March 22, 2012, 07:06:01 PM »
CAN is a shared bus topology.  Many devices can and do hang off it at once.
If your vehicle uses the 9141 protocol, it was not made for the US market and therefore was not required to support the CAN interface at the OBDII connector.  The likely only difference between the US and Canadian versions is the Engine Control Module.  The US used the New CAN version and Canada was the dumping ground for the older 9141 modules.

Forcing UG to use CAN will cause UG to attempt to connect only using CAN.  I suspect that if the protocol is forced, it will scan for two minutes and then shutdown with no success.

Offline speedlever

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Re: Protocol
« Reply #4 on: March 22, 2012, 09:04:39 PM »
I need to read up in the manual about forcing the protocol. But I don't believe I have anything to lose. By everything I read, I should have 29-bit CAN on my 2008 Honda.

I'll disconnect the other OBDII device before doing this.

Offline speedlever

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Re: Protocol
« Reply #5 on: March 26, 2012, 10:45:49 AM »
Now I know why my 2008 Honda Ridgeline won't work with CAN bus protocols. My OBDII port is not wired for CAN.

See this posting for more details:
http://www.ridgelineownersclub.com/forums/showpost.php?p=632617&postcount=17

Now to have a discussions with Honda.