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Conjurer · 10-17-2019, 05:01 PM

Greetings. I have a 2001 Itasca Horizon, running a 350 Cat turbo on a Freightliner chassis. My check engine light came on and need to run a diagnostic, but can't locate the OBD port. Called both Winnebago and Freightliner proper. Neither one was of any help. Took it to a truck repair shop that works exclusively on motorhomes with Cat engines on Freightliner chassis. They spent 90 minutes searching for the port, but was unsuccessful in locating it

. I was told by both Winnebago and Freightliner the port I was looking for was a 16 pin connector with a Black screw off cap. Help!

dc8cappie · 10-17-2019, 06:24 PM

The rear one is! Open the rear engine cover. Mine is dead center above the radiator on the metal panel. Mine’s round.

Conjurer · 10-18-2019, 11:39 AM

Quote:

Originally Posted by dc8cappie

The rear one is! Open the rear engine cover. Mine is dead center above the radiator on the metal panel. Mine’s round.

May I ask what year your coach is? As I mentioned mine is 2001. I have looked in the rear engine compartment everywhere and I can't find it.

dc8cappie · 10-19-2019, 06:43 AM

Quote:

Originally Posted by Conjurer

May I ask what year your coach is? As I mentioned mine is 2001. I have looked in the rear engine compartment everywhere and I can't find it.

My signature says 2005 Itasca Meridian.

Mine also has one somewhere around the steering wheel column but don’t ask me where.

luvlabs · 10-19-2019, 09:18 AM

OBD I or II is not the data protocol used on these big diesels. J1939 is the current protocol but there was one used before that as well.

BobGed · 10-19-2019, 09:29 AM

Quote:

Originally Posted by luvlabs

OBD I or II is not the data protocol used on these big diesels. J1939 is the current protocol but there was one used before that as well.

I believe the one you're thinking of is the J1708 data bus which would be applicable to the OP's YM coach.

sawmillman · 10-19-2019, 06:29 PM

The one on mine under the dash was almost impossible to find and unusable when I found it. It was just right of the steering column under 15 miles of wiring. I finally found it by using a mirror . When I did find it I took it loose and moved it back to the firewall so I could plug in a Scanguage. Its most likely under there you may have to dig. It took me several attempt's to find mine.

wstalker · 10-20-2019, 07:26 AM

On a 2005 Winnebago Vector there is one that will smack you in the face at the engine compartment and another under the steering area. They are round and sometimes have a cap. Good luck.

imnprsd · 10-27-2019, 02:38 AM

My 2004 Itasca "Horizon" 40AD as the port in the engine bay... this is the one you will want to hook up to, but you can get the same data off the port behind the floor kick-plate to the left of the brake.

This aluminum plate can be bent back... then you will see the round connector you are looking for.

FYI... I recently purchased this SCAN TOOL on Amazon for $120. It works great and now I travel with it just because...

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I had a 330 CAT once... and my problem was the accelerator pedal had a Throttle Position Sensor (TPS) go out. It either killed the engine or left me in limp mode. Do you have any other symptoms to share?

FYI... You should know, your ECM and Tranny computer store codes. These have time stamps so anytime you see your "check engine light" come on you should note the date and time to compare with your scan history.

History can be important to diagnosing your troubles...

cbeierl · 10-27-2019, 09:57 AM

Here's what it looks like under the dash on my 2005 Vectra with the 350 CAT:

The same connector is also available in the rear above the radiator.

Don't know if it's the same on your 2001, however.

David K · 11-05-2019, 07:01 PM

Your's may be in the same spot as mine was ---- behind the foot rest that you can put your left foot on. I had to remove the footrest and behold ---- there it was attached to the "firewall". You will find several screws that hold that foot rest in place --- use your fingers to find them and remove so you can remove the footrest. Why it was mounted there is a mystery as it was not available to plug in for analysis.

FIRE UP · 11-06-2019, 09:57 AM

Quote:

Originally Posted by Conjurer

Greetings. I have a 2001 Itasca Horizon, running a 350 Cat turbo on a Freightliner chassis. My check engine light came on and need to run a diagnostic, but can't locate the OBD port. Called both Winnebago and Freightliner proper. Neither one was of any help. Took it to a truck repair shop that works exclusively on motorhomes with Cat engines on Freightliner chassis. They spent 90 minutes searching for the port, but was unsuccessful in locating it

. I was told by both Winnebago and Freightliner the port I was looking for was a 16 pin connector with a Black screw off cap. Help!

Conjurer,
First off, just wondering, you say your coach is an '01, correct? And, you say it's sporting a "350HP" CAT, correct? Well, if it's an '01, I'm gonna assume that, your CAT engine is a 3126. While I'm definitely no expert on any of this, I've just been around these types (and brands) of RVs for quite a while and, I was not aware that the 3126 came in a 350HP version. About 99.99999% of the time, the 3126 was either a 300 or 330HP version. But, it's not the end of the world if you do have a 350HP version, it just means I've never heard of a 350HP 3126.

Second, again, no expert but, a very large percentage of Freightliner chassis' do have TWO of those diagnostic ports. The first one, typically, is located somewhere near the top of the radiator and facing the rear of the coach, typically in plain sight from the rear of the coach. The second one, is typically up front, and really close to the firewall, tucked up behind or, possibly to the left of the steering column. It's been a bear to find for about 99.999% of us. It took me a while but, it was actually attached to the fire wall.

I decided that, that was an asinine place for such an important item. So, I moved it to right at the bottom of the dash, out of the way but, VERY easily accessible.

Third, for Freightliner to be of no help, sure sounds odd to me. It's THEIR CHASSIS, they should know EXACTLY where your diagnostic port(s) are! Now, your coach should have came with the infamous "VDC" or, Vehicle Data Computer. It's located alongside the frame rails, in the engine compartment. It's the primary "Go-between" between your engine/trans/ABS and air system, and, your gauges. It's main communications is a J1587 datalink. It's a three wire communications system for all that.

The connector or, data port, is not a "16 pin" port, it's a nine pin port and it's round, not rectangular. The J-1939 Datalink system did not come out 'till mid of '03 and also utilizes a 3-wire communication system. But, it's primarily associated with the "MMDC" or, Multi-Module-Data-Computer. It's an upgrade to the VDC but, also uses the 9-pin data port, also typically located just above the radiator on Freightliner rear radiator coaches for late '03 and up.

So, I don't know if I've helped any but, it's some info for ya.
Scott

P.S. As usual, Chris comes through with great info, like the pic of the data port.