Alternate data link connector?

David11946

Original poster
Member
Apr 24, 2012
14
New York
Hi guys,

I have a 02 Trailblazer 4.2L, I6 and I have had trouble lately since a tune up. I had purchased a set of ignition coils on ebay (bad idea), and a set of NGK iridium plugs. I cleaned my throttle body, gapped the plugs according to spec and swapped everything in. The car ran with exceptional performance for one day. On the second day, it developed a misfire on the way home. I pulled the coils and plugs and checked 'em. The plugs were fine but a shop told me that #4 had a misfire. I swapped #4 for a new coil and it ran fine for a month. Then another coil dropped so I put all the old coils back in and it runs ok. I went out to buy a OBDII scanner so I can check my own codes and I plugged it into the under dash connector but nothing happened when I put the key in the on position. After a number of tries, I'd remembered that the guy at the shop had the same problem. He instead connected his diagnostic machine from under the hood. I looked under there but I guess I'm missing something.
Is there another data link connection under the hood like the one under the dash so I can retrieve codes with my scanner or is it a different kind of connector?

I really would appreciate a point in the right direction. I love my TB but I'm a working man. So like everyone else, I gotta have the car running Monday to Friday without fail. Weekends is all I have for solving transportation problems and enjoying my machines.

Sorry if this is a topic that was discussed already but I searched and couldn't find it.
Thanks
 

Sparky

Member
Dec 4, 2011
12,927
Check the fuse for the lighter socket. I think the OBDII port is powered by the same circuit IIRC.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
It's underhood fuse #13. Evil GM design not at the very least adding a footnote to the fuse chart in the Owner's manual. They want to FORCE you to pay the dealer to fix a trivial thing like the OBDII port power.

Also, ONLY iridium Delco 41-103 plugs have 100% good feedback from owners here and on our previous site. Thousands of owners can't be wrong.

PS: Welcome fellow San Diegan!
 

David11946

Original poster
Member
Apr 24, 2012
14
New York
the roadie said:
It's underhood fuse #13. Evil GM design not at the very least adding a footnote to the fuse chart in the Owner's manual. They want to FORCE you to pay the dealer to fix a trivial thing like the OBDII port power.

Also, ONLY iridium Delco 41-103 plugs have 100% good feedback from owners here and on our previous site. Thousands of owners can't be wrong.

PS: Welcome fellow San Diegan!

Thank you for that info. I was actually thinking about the Delco plugs after I bought the NGKs. I'll I may just switch them out when I swap in new coils. I will look into that fuse as soon as The auto part stores open. Hey, fellow San Diegan, Do we have meet & greets out here? Any Trailblazer/Envoy gatherings?
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
:tiphat: Welcome:tiphat:

In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/

Also, when you get the new AC Delco Iridium plugs, they should have the gap set from the factory.
If/when you check them, be very careful. The iridium is brittle and can be broken off when/if you try to gap them.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
David11946 said:
Hey, fellow San Diegan, Do we have meet & greets out here? Any Trailblazer/Envoy gatherings?
We haven't been as active as the midwest or east coast crews. I run offroad trail rides and campouts from time to time, but you have to be lifted to get anywhere I go. I have all the tools and have helped about ten local members put in lift kits and other repairs, but almost none of them still have their trucks or stayed in the area (those darn Marines). I think the last meet we had was a BBQ in Mission Bay. Always looking for an organizer, if you're volunteering. You anywhere near North County?
 

signalnc

Member
Dec 28, 2012
249
just to add my 2 cents 'cause I can't keep my mouth shut--I had put in some autolite double platinum spark plugs and I lost 2 coil packs within 2 months after I did that. not sure if they were the cause but I replaced them with the ac delco's
 

mark'stb

Member
Dec 17, 2011
94
I had the terminal for the 12 volt back out of my aldl connecter. Had to replace the terminal.
 

David11946

Original poster
Member
Apr 24, 2012
14
New York
Thank you for all the input guys. I actually have a lot of work to do on my TB (a little road rash and some minor repairs here and there due to daily grind and travel. I bought a lot of pieces such as new headlights and LED tail lights, a couple of overhead consoles and there's a lowering kit I'm looking at picking up next week). I hope that I can try to also contribute info to the website in the future with any of my planned mods. Hopefully, I can be as helpful as many of you guys have been to me.

I was also one of the old Trailvoy.com members and I wondered what had happened there (Roadie cleared that up for me....Thanks for the link, Roadie). Maybe I can post some pics of my TB soon.

Thanks again!
 

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