Dead OBD2 Port?
01-26-2012, 06:28 AM
#1
Registered User
Thread Starter
Join Date: Jan 2012
Location: Northern Colorado
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Dead OBD2 Port?
Has anyone ever had a problem with a dead OBD2 port? I can't get any of the scanners at my local auto parts stores to even hook up to the port (recognize that they are connected to the truck). I need to pull a CEL code to figure out why my truck is idling like crap. Does anyone know the procedure for using the "Diagnostics" box under the hood to pull a CEL code instead? Any help would be greatly appreciated.
01-26-2012, 08:57 AM
#2
If it's got the "Diagnostics" box it probably has OBDI, not OBDII(despite having an ODBII port). Which I assume means it's a pre-96 model with a 3VZ-E.
Anyways checking the codes is going to be the same on all models with an OBDI "Diagnostics" box. You short/jump the check connectors with a paperclip, and basically count the number of times the CEL blinks/flashes.
And if it's got a 3VZ-E then the codes for it are in the 93 PU FSM
http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf
There's a possibility that you do have OBDII, IF it's not a 3VZ-E(despite having the "Diagnostics" box). Then you could also possibly have a dead OBDII port.
Anyways checking the codes is going to be the same on all models with an OBDI "Diagnostics" box. You short/jump the check connectors with a paperclip, and basically count the number of times the CEL blinks/flashes.
And if it's got a 3VZ-E then the codes for it are in the 93 PU FSM
http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf
There's a possibility that you do have OBDII, IF it's not a 3VZ-E(despite having the "Diagnostics" box). Then you could also possibly have a dead OBDII port.
HINT:
If your display shows ”UNABLE TO CONNECT TO VEHICLE”
when you have connected the cable of the OBD II scan tool or
TOYOTA hand−held tester to DLC3, turned the ignition switch
ON and operated the scan tool, there is a problem on the vehicle
side or tool side.
If your display shows ”UNABLE TO CONNECT TO VEHICLE”
when you have connected the cable of the OBD II scan tool or
TOYOTA hand−held tester to DLC3, turned the ignition switch
ON and operated the scan tool, there is a problem on the vehicle
side or tool side.
- If communication is normal when the tool is connected to
another vehicle, inspect DLC3 on the original vehicle. - If communication is still not possible when the tool is connected
to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the
tool’s instruction manual.
Last edited by MudHippy; 01-26-2012 at 09:27 AM.
01-26-2012, 03:56 PM
#4
Contributing Member
Join Date: Nov 2010
Location: Columbia River Gorge, Oregon...east side
Posts: 5,125
Likes: 0
Received 2 Likes
on
2 Posts
Check the OBD fuse in the engine compartment fuse box.
My 95.5 3.4L has the diagnostic box on the attached to the manifold and also the OBDII under the dash that works just fine.
My 95.5 3.4L has the diagnostic box on the attached to the manifold and also the OBDII under the dash that works just fine.
01-26-2012, 04:59 PM
#5
So what's the diagnostic box do on an OBDII system? Is it even wired to anything? I can't find any references to it having any use on an engine with OBDII. Am I not looking hard enough?
01-26-2012, 05:25 PM
#6
Contributing Member
Join Date: Nov 2010
Location: Columbia River Gorge, Oregon...east side
Posts: 5,125
Likes: 0
Received 2 Likes
on
2 Posts
Looking into the FSM: The Diagnostic box (DLC1) under the hood is used to check ignition timing.....and what else?
http://www.ncttora.com/fsm/1996/SIL/...gntim/insp.pdf
Yikes....this is my post 666 since becoming a member here.
Last edited by rworegon; 01-26-2012 at 05:36 PM.
01-26-2012, 06:03 PM
#7
Looking into the FSM: The Diagnostic box (DLC1) under the hood is used to check ignition timing.....and what else?
http://www.ncttora.com/fsm/1996/SIL/...gntim/insp.pdf
http://www.ncttora.com/fsm/1996/SIL/...gntim/insp.pdf
Trending Topics
01-26-2012, 06:18 PM
#8
Contributing Member
Join Date: Nov 2010
Location: Columbia River Gorge, Oregon...east side
Posts: 5,125
Likes: 0
Received 2 Likes
on
2 Posts
Oh, according to page DI-10 here:
http://www.ncttora.com/fsm/1996/SIL/...zfe/preche.pdf
you then continue on page IG-1, Ignition section:
http://www.ncttora.com/fsm/1996/SIL/.../ignsy/ovi.pdf
Sorry, OP for the OBD diagnostic port detour.
Did you get your OBDII port working??
http://www.ncttora.com/fsm/1996/SIL/...zfe/preche.pdf
you then continue on page IG-1, Ignition section:
http://www.ncttora.com/fsm/1996/SIL/.../ignsy/ovi.pdf
Sorry, OP for the OBD diagnostic port detour.
Did you get your OBDII port working??
01-26-2012, 06:40 PM
#9
Kick panel fuses... 
One of the things the diagnostic port in the engine bay is used fer is to read/reset the SRS (airbag) system codes...since those cannot be read/reset via the ODBII port.
One of the things the diagnostic port in the engine bay is used fer is to read/reset the SRS (airbag) system codes...since those cannot be read/reset via the ODBII port.
01-31-2012, 04:04 PM
#11
BUT, you can read/reset them using an OBDII scan tool(atleast the one Toyota uses). See pages DI-365 through DI-367 for the details.
http://www.ncttora.com/fsm/T-100/199...T100%20FSM.pdf
So yeah, I wonder what happened with the OP here? Finally got some decent advice in the last couple of posts before this one(though I can't see how disconnecting the battery would work, or how/why Toyota doesn't recommend doing that if it does). Anyhow, maybe he needed the advice, maybe he didn't...
Last edited by MudHippy; 01-31-2012 at 04:32 PM.
02-17-2012, 02:25 PM
#12
Registered User
Thread Starter
Join Date: Jan 2012
Location: Northern Colorado
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Still lookin into the dead port, there is no power to the terminals int the port. The truck had a new engine put in it before I bought it, and i'm suspecting that they never hooked it up.
02-17-2012, 10:26 PM
#14
From my 1998 FSM...
Pin 16 (violet-1998...not sure what color it would be on yer T-100 since you haven't told us) should be 12V power which is fused via the ODB2 fuse which gits it's power via a black/green wire from the EFI 15A fuse. The EFI fuse gits it's power via a white/red wire from the 100A Alt fuse which gits it's power from the battery via a white wire from the positive post.
Pin 4 (black/white) should be ground which is connected to the right kick panel. Yer data lines are Pin 5 (brown) and Pin 7 (white, shielded).
02-18-2012, 12:22 PM
#15
Registered User
Thread Starter
Join Date: Jan 2012
Location: Northern Colorado
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
alright, after actually taking 5 min to look it over, there was just no fuse in there at all. Actually no fuses in the entire lefthand bank of 4. It says one of them is supposed to be blank but not all. How has my truck been running well without these 3 fuses in there?
02-19-2012, 06:29 AM
#16
Has anyone ever had a problem with a dead OBD2 port? I can't get any of the scanners at my local auto parts stores to even hook up to the port (recognize that they are connected to the truck). I need to pull a CEL code to figure out why my truck is idling like crap. Does anyone know the procedure for using the "Diagnostics" box under the hood to pull a CEL code instead? Any help would be greatly appreciated.
Last edited by BamZipPow; 02-19-2012 at 06:30 AM.
02-19-2012, 06:56 AM
#17
Registered User
Thread Starter
Join Date: Jan 2012
Location: Northern Colorado
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
I put new fuses in there yesterday as soon as I realized the problem. I now have a functioning OBD 2 port, which by the way was able to narrow my original problem (erratic cold idle thread) down to a short between the ECT and brakelight circuits that I now need to find. The little "put your seat belt on guy" light now flashes at me when I turn the truck on too. Other than those 2 things there is no noticeable difference in how my truck is running.That seems extremely strange to me, those fuses are supposed to power the ECU. I would think the truck wouldnt run without any power to ECU? or at least run really terribly so that it is obvious there is a problem.
Last edited by FoCo_4_Low; 02-19-2012 at 06:57 AM.
02-19-2012, 07:00 AM
#18
It may take the ECU about 150 miles to determine the proper fuel trims based on yer driving habits.
How good are yer plugs/wires? Are you using the proper spark plugs? Dual ground electrodes? I went with the NGK Platinum Laser plugs...
You should consider gitting an Ultragauge...
How good are yer plugs/wires? Are you using the proper spark plugs? Dual ground electrodes? I went with the NGK Platinum Laser plugs...
You should consider gitting an Ultragauge...
02-19-2012, 07:34 AM
#19
Registered User
Thread Starter
Join Date: Jan 2012
Location: Northern Colorado
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
The plugs are Denso- with the dual electrodes and have <40,000 on them so they are tops. Haven't taken them out lately to check what they look like, might be worth doing. The wires are doing alright but will be due for replacement in the next year or two here. That Ultragauge does look really useful, might have to get one when I have a little extra $$ to drop (only $70 bucks right now though. not bad!).
10-17-2012, 06:03 PM
#20
obd port not working in my 98 4runner too,also the fuel pump keeps priming endlessly
obd port pins are ok 4 and 5 are ground 7 is signal from ecu and 16 is b+ all ok,mine runs fine but every morning the cel comes on .
bad ecu?
obd port pins are ok 4 and 5 are ground 7 is signal from ecu and 16 is b+ all ok,mine runs fine but every morning the cel comes on .
bad ecu?
Thread
Thread Starter
Forum
Replies
Last Post
zombie_barbarossa
95.5-2004 Tacomas & 96-2002 4Runners
3
10-02-2015 10:54 PM
