PT Cruiser Forum  
Advertisements
       

Go Back   PT Cruiser Forum > General Forums > Tech & Performance Forum

PT Cruiser Forum

Advertisements
No grounds at OBD ii plug pins 4&5

 
Like Tree8Likes
  • 4 Post By rckstein
  • 1 Post By JoeX
  • 3 Post By betterred

Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 19 May 2017, 09:36 pm
Fresh Cruiser
 
Join Date: Apr 2009
Location: Driveway & Highway
Posts: 14
Question No grounds at OBD ii plug pins 4&5

2006 PT 2.4 non turbo

Re: At the OBD II test plug on vehicle....

I do have voltage (12v) at pin 16 relative to a alternate body ground but I have no continuity from either pins 4 or 5 to body ground nor 12v between pin 16 and pins 4 or 5 with or without key on.

Looks like behind the OBD II plug that 4 and 5 join up then proceed as a single black wire to never never wire harness-land...

The whole discovery started when a check engine light was thrown which at the same time stopped sending signals to control cooling fan.

Everything else on vehicle works.

Can't read codes with code reader without chassis or signal grounds(@4&5).

Question1: Do I tap into the ground wires (4&5) to establish good parallel grounds with existing and hopefully get Code reader to pull off the codes that can shed some light ?

I gather I have a grounding issue or a (ECM PCM ECU) unit issue ... Obviously would hope to only have to address a ground issue.

Question2 : Does anyone know where the 4&5 grounds terminate next downstream of the OBDii plug so I can check to that point? I am guessing the ground may pass through one of the 4 plugs through the (ECM PCM ECU) unit ?... But only guessing.

Thanks in advance for any help!
Reply With Quote
  #2 (permalink)  
Old 19 May 2017, 10:34 pm
rckstein's Avatar
Banned
 
Join Date: Dec 2010
Location: Texas
Posts: 15,518
Default Re: No grounds at OBD ii plug pins 4&5

This diagram shows that pins 4 & 5 in the Data Link connector go to ground G102, which is located in the left front fender. These are the easiest grounds to get to, but you will have to remove the battery and air box.





Quote:
Originally Posted by LionPT View Post
Check & clean these ground wires behind the air box.

Do you have a copy of the Service Manual? It also has the wiring diagram.

If not, you can download a copy of it from this website:

JustCloud : OEM Service Manuals

The only one you need to download is:

2006-2010 OEM Svc Manual.zip

You will need WinZip to open the file, but you can also download a free version of that from the internet.

Welcome to the forum

Last edited by rckstein; 20 May 2017 at 02:52 am.
Reply With Quote
  #3 (permalink)  
Old 20 May 2017, 02:48 am
Senior Cruiser
 
Join Date: Jan 2014
Location: SW PA
Posts: 1,336
Default Re: No grounds at OBD ii plug pins 4&5

Do your self a favor, remove the ground with several wires attached to it and cut the small wires off. Get several new eyelets and strip the wires back about 5/8 inch, I inserted two wires into each eyelet then soldered them to make the best connection.
I also removed and did the same with larger eyelet but I was able to reuse the larger eyelet.
All my sensor grounding problems were fixed by above procedure.
rsrocket1 likes this.
__________________
Addicted to Mopar You can tell how old I am..
65 Dodge Coronet 6 cyl 2dr Post
66 Ply Satellite with 273 engine swap to 69 340 4spd
70 340 4spd Dart Swinger "Those were the days my friend"
73 Charger SE
Had a few Vetts on the way 69, 85
Several Neons some flips
01 Sebring flip
Cruiser's 01, 220K Gone to a new home
Cruiser 03 133K Gone to a new home
Cruiser 06 110K Project Gone to new Home
Cruiser 05 Ltd 120,809 bought with broken belt Oct2015
May 16 Resurrected to once again roam the streets.

20 Miles South Of Pittsburgh
Reply With Quote
  #4 (permalink)  
Old 27 May 2017, 11:37 am
Fresh Cruiser
 
Join Date: Apr 2009
Location: Driveway & Highway
Posts: 14
Default Re: No grounds at OBD ii plug pins 4&5

rckstein - Thanks for the links and diagrams/photos .. Much appreciated !!

JoeX - The small wires in that cluster were corroded and easily detached. They did require reconnecting. Checked remaining wires at that ground point along with the ground point where the battery (-) connects to as well. All good now !

BTW - In the process it was discovered that (since my check engine light would still not reset "i.e. P0481"and cooling fan still did not operate), the fused B+ (A16 10RD/BR) between the TIPM and the Cooling Fan Module had a high resistance. I checked the B+ wire between (within and just prior to) the two termination points so the issue in the wire appeared to be buried in the wiring harness in between. This is strange because (unless I missed it) I did not see a splice in the wire diagram (thxs again rckstein for manual links!) and that is a heavy gage wire to have a break/weak point in it. Note: It did not have any resistance to ground just within the wire.

What is also important to note in my troubleshooting is that I was getting a 12V reading to the high and low speed relays but would not fire off the fan (due to the high resistance or whatever was causing the high resistance in the B+ feed from TIPM) but could run the fan direct from battery. This can make you start to feel like you are loosing it . I believe the manual does note in various troubleshooting sections to check resistances in wires (but "reading" the manual is like peeking at the answers isn't it ..? )...

In any case, I reestablished a good B+ (A16 10 RD/BR) feed between the TIPM and the main fan connector (DK Gray 4 wire connector bottom Left front cooling fan assy) and P0481 is gone and fan operates on the hi and low speeds when it is suppose to !!

Thanks again rckstein and JoeX for you help and advice !

P.S. - As you can tell I would never make a livable living repairing vehicles and I must be bored
Reply With Quote
  #5 (permalink)  
Old 27 May 2017, 12:26 pm
rckstein's Avatar
Banned
 
Join Date: Dec 2010
Location: Texas
Posts: 15,518
Default Re: No grounds at OBD ii plug pins 4&5

Glad to hear you got your PT fixed
Reply With Quote
  #6 (permalink)  
Old 27 May 2017, 01:06 pm
Senior Cruiser
 
Join Date: Jan 2014
Location: SW PA
Posts: 1,336
Default Re: No grounds at OBD ii plug pins 4&5

So simple but so difficult when you cannot actually see what broke. You have restored my thoughts of humanity and THANKS for posting the fix..

Cruize on and on... See you down the highway..
__________________
Addicted to Mopar You can tell how old I am..
65 Dodge Coronet 6 cyl 2dr Post
66 Ply Satellite with 273 engine swap to 69 340 4spd
70 340 4spd Dart Swinger "Those were the days my friend"
73 Charger SE
Had a few Vetts on the way 69, 85
Several Neons some flips
01 Sebring flip
Cruiser's 01, 220K Gone to a new home
Cruiser 03 133K Gone to a new home
Cruiser 06 110K Project Gone to new Home
Cruiser 05 Ltd 120,809 bought with broken belt Oct2015
May 16 Resurrected to once again roam the streets.

20 Miles South Of Pittsburgh
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
no grounds = transmission problems? cdefn General PT Cruiser Discussions 4 21 Jan 2016 04:32 pm
Chrysler OEM Grounds Effect installation instructions JoeCruiser Exterior Accessories Forum 2 18 Jan 2013 02:07 pm
New wire harness kit has 2 constant and 2 grounds? fishkiller12672 Sound and Security Forum 4 28 Oct 2011 10:36 am
Where are all the grounds located on the PT clark6 Tech & Performance Forum 5 17 Mar 2011 02:42 pm


All times are GMT -5. The time now is 09:12 am.




Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.
vB.Sponsors