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99 ECM Connector Pin Out

F

fzsk4p

NAXJA Forum User
Location
America
Been going nuts trying to find the C1,2 and 3 ECM pinouts for the 98-99 OBD2 connectors.

Looked at Morris info center and searched here and on the interweb.

Once saw a simple picture of each ECM connector with the pin location/function and wire color. Darned if I can find it now......

Anybody remember seeing one of those diagrams ? I would sure appreciate a link or picture.

Thanks
 
Thanks Mud, that is what I was looking for.

Converting to OBD2 in order to take advantage of the data logging and custom ECM programming available now in a stroker equipped vehicle.

Have a mystery connector up by the TB, IAC, IAT area of the harness that I am trying to figure out what it does.

3 wires, one being a Purple (Violet)White that goes up the Black C1. Don`t see that color combo in the chart so perhaps what I looking for is a 98 pin out.

I do have the Gray/Black in C1- 8 and the chart list`s it as being the crank signal connector.

Looks like 98 and 99 might be different ??

Need to do some probing with the meter.
 
Last edited:
fzsk4p said:
Thanks Mud, that is what I was looking for.

Converting to OBD2 in order to take advantage of the data logging and custom ECM programming available now in a stroker equipped vehicle.

Have a mystery connector up by the TB, IAC, IAT area of the harness that I am trying to figure out what it does.

3 wires, one being a Purple (Violet)White that goes up the Black C1. Don`t see that color combo in the chart so perhaps what I looking for is a 98 pin out.

What are the other 2 wire colors at that connector?

I do have the Gray/Black in C1- 8 and the chart list`s it as being the crank signal connector.

Looks like 98 and 99 might be different ??

Need to do some probing with the meter.
Click to expand...

98 and 99 PCM pinouts should be the same, with a few exceptions for options not available in '98.

What year XJ did you get this harness from?
 
Thanks for responding Sidewinder.

Had a chance to do a little probing.

Pretty sure what I am looking at the crank sensor connector.

C1-8 is the sensor signal with the Grey/Black

C1-17 is 5 volt supply with what is supposed to be a Orange but mine is Violet/White. The V/WHT was throwing me off.......

The other wire is Black/Blue which I have not found yet. Harness is still taped up in that region. My guess is that it will be sensor ground and common throughout. FWIW the seal around the sensor is brown instead of the usual green or black.

Thanks
 
fzsk4p said:
Thanks for responding Sidewinder.

Had a chance to do a little probing.

Pretty sure what I am looking at the crank sensor connector.

C1-8 is the sensor signal with the Grey/Black

C1-17 is 5 volt supply with what is supposed to be a Orange but mine is Violet/White. The V/WHT was throwing me off.......

The other wire is Black/Blue which I have not found yet. Harness is still taped up in that region. My guess is that it will be sensor ground and common throughout. FWIW the seal around the sensor is brown instead of the usual green or black.

Thanks
Click to expand...

What year XJ harness is this? Is it in fact an XJ harness?

The '99 does not have a three pin connector wth the color codes you state in that area, or anywhere in the engine bay for that matter.

Keep in mind that you are trying to go from an OBD I protocol to a OBD II protocol, and that the XJ OBD II CCD Bus requires two termination and one bias circuit(s) inorder to function. The instrument cluster in the XJ OBD II has a termination and bias circuit and the PCM has a termination circuit. The OBD II protocol CCD Bus will not work without these circuits.

See schematic below.

What say you?

DLC.jpg
 
Thanks again Sidewinder.
I looked at the diagnostic port and it matches up perfectly with your drawing. The harness is from a 99 4 door Sport with 4WD.

Keep in mind that you are trying to go from an OBD I protocol to a OBD II protocol, and that the XJ OBD II CCD Bus requires two termination and one bias circuit(s) inorder to function. The instrument cluster in the XJ OBD II has a termination and bias circuit and the PCM has a termination circuit. The OBD II protocol CCD Bus will not work without these circuits.

This I need to work on to gather the information so I understand it. My intail impression was that so long as the diagnostic port was powered, grounded. Has the SCI and the CCD bus from the ECM (C3) it would "talk".

Here is a couple pictures with the offending connector on the right. Then a broader overview of the area of the harness.





Now to be honest and frank what I am doing is retrofitting this harness into a lowly OBD1 YJ.


I chose the XJ harness because the PDC is in about the same position as the YJ/TJ but the ECM being on the drivers side front fender gives me a longer main trunk line for packaging. Plan is to take advantage of the longer wires and mount the ECM in the cabin.

The YJ is set up with stand alone gauges so I need no communication with the ECM in that regard. No AC, cruise etc and best of all in Michigan with are not burdened with emissions laws. Meaning all the emissions stuff can be eliminated.

The plan is to give the ECM the inputs it needs to run and allow it to talk via the diagnostic port via the twisted wire. Everything else will be pared away. Of course the cal that is flashed into the ECM will "block" the missing components/functions so as not to be throwing code after code..

It will be a bit of a challenge integrating the two systems for ignition switch, fuel system, reverse lights, dash power and the like but the YJ is pretty simple and I have rewired it once already.
 
Last edited:
fzsk4p said:
Thanks again Sidewinder.
I looked at the diagnostic port and it matches up perfectly with your drawing. The harness is from a 99 4 door Sport with 4WD.

Keep in mind that you are trying to go from an OBD I protocol to a OBD II protocol, and that the XJ OBD II CCD Bus requires two termination and one bias circuit(s) inorder to function. The instrument cluster in the XJ OBD II has a termination and bias circuit and the PCM has a termination circuit. The OBD II protocol CCD Bus will not work without these circuits.

This I need to work on to gather the information so I understand it. My intail impression was that so long as the diagnostic port was powered, grounded. Has the SCI and the CCD bus from the ECM (C3) it would "talk".

Here is a couple pictures with the offending connector on the right. Then a broader overview of the area of the harness.





Now to be honest and frank what I am doing is retrofitting this harness into a lowly OBD1 YJ.


I chose the XJ harness because the PDC is in about the same position as the YJ/TJ but the ECM being on the drivers side front fender gives me a longer main trunk line for packaging. Plan is to take advantage of the longer wires and mount the ECM in the cabin.

The YJ is set up with stand alone gauges so I need no communication with the ECM in that regard. No AC, cruise etc and best of all in Michigan with are not burdened with emissions laws. Meaning all the emissions stuff can be eliminated.

The plan is to give the ECM the inputs it needs to run and allow it to talk via the diagnostic port via the twisted wire. Everything else will be pared away. Of course the cal that is flashed into the ECM will "block" the missing components/functions so as not to be throwing code after code..

It will be a bit of a challenge integrating the two systems for ignition switch, fuel system, reverse lights, dash power and the like but the YJ is pretty simple and I have rewired it once already.
Click to expand...

Those fuel injector connectors look strange. I hate to keep harping on this but are you sure that harness came from a '99 XJ. Did you remove the harness from the '99 doner XJ?
 
Well, I removed it myself and the XJ had the side marker lights on the fender rather then integrated with the headlights, which I think came out in 96/97 revision.

The door tag said 99.........

Sheesh, I hope I don`t have some goofy mongrel because needless to say there is a lot of wire tracing to do.



NINJA EDIT.. Compared the injector connectors with an OBD1 YJ harness I have and they are the same. Then compared to a cut up TJ harness that a friend gave me and I do see a difference.

Could I be having a case of CRS on the model years ? Is there an "earlier" OBD2 XJ harness that had OBD1 style parts in it in regards to wire colors and connector shapes ??
 
Last edited:
Yeah, I just looked at my rig (99 xj) and I dont have those wires in that area. I also checked a 97 FSM and there is no wires with that color in that area. Can you take a picture of the PDC that is attached to that harness?

fzsk4p said:
Well, I removed it myself and the XJ had the side marker lights on the fender rather then integrated with the headlights, which I think came out in 96/97 revision.

The door tag said 99.........
Click to expand...

exterior.jpg


Did it look like that?
 
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sidewaysstarion said:
Yeah, I just looked at my rig (99 xj) and I dont have those wires in that area. I also checked a 97 FSM and there is no wires with that color in that area. Can you take a picture of the PDC that is attached to that harness?
Click to expand...







Hope this helps to ID what in the heck I ended up with.........
 
Looking at the connectors and the PDC I have a feeling you grabbed a 96 XJ engine harness.
here is a 96 throttle body.
maxresdefault.jpg


96 is a bastard year that used alot of early model sensors on a late model computer.
 
You are a well versed XJ owner. Suspect the CRS did kick in and you are indeed correct.

Now having said that, one thing I was aware of going into this swap is that the TB (for example) connectors were different for OBD2. As I looked up some of the common sensors to see what I might have to replace to match up to the new harness. Flat terminals vs. pins as an example.

Went and compared the CTS, TPS and IAC connectors this "new" harness has with what is listed for a 99XJ.

Here is TPS
Example 93 OBD1
http://shop.advanceautoparts.com/p/...8470345-P?searchTerm=sensor+throttle+position#

Example 99 XJ OBD2
http://shop.advanceautoparts.com/p/...8480649-P?searchTerm=sensor+throttle+position#

Sure enough I think you are correct. I snagged a 96. Having said that, might this be a blessing in disguise as now all my current sensors will mate up. Or are there enough serious fundamental differences in the electrical architecture of the 96 vs. the 99 that I should start over ? :explosion

I can probe wires and so long as they in the right cavities it should work, right ?

Dam and to think I froze my butt off stripping the XJ harness thinking I was golden.......
 
For your application, the a 96 harness is the perfect harness because it will work with your early model sensors and it is also setup to drive the OBD1 tach where the later years the cluster was all CCD buss. If you did grab the 96 computer, you're probably going to want to replace that with a 97-01 computer. If you try and flash a 96 computer with an SCT it will brick the ecu and the programmer.

But the nice thing about the JTEC is the pinout is the same for all of the years, just some pins are populated and others aren't.
 
sidewaysstarion said:
For your application, the a 96 harness is the perfect harness because it will work with your early model sensors and it is also setup to drive the OBD1 tach where the later years the cluster was all CCD buss. If you did grab the 96 computer, you're probably going to want to replace that with a 97-01 computer. If you try and flash a 96 computer with an SCT it will brick the ecu and the programmer.

But the nice thing about the JTEC is the pinout is the same for all of the years, just some pins are populated and others aren't.
Click to expand...

Thanks again SW.
I have to admit that I feel like a real butthole for having wasted folk`s time by giving them wrong model years of the harness. There at the pick and pull all the OBD2 Cherokees started looking the same after a while.

Knew I wanted OBD2, a dist. harness, and one that was unmolested. After looking at about 10 vehicles and doing the comparisons, well you know.........:bunny:

So now I am reading your comment and thinking, darn boy you did good by picking up that mongrel 96 harness.......:rof:

Fortunate that all the vultures had stripped the OBD2 ECM`s so I did not blow $$ on an ECM that will not work They did have OBD1 SBEC ECM`s if anyone wants one.

On to a 96 shop manual for colors and such.
 
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