Explorer OBD2 Harness Re-work

[904Bronco]

Garry will get around to answering you eventually...

He is typically 3-4 months out with Explorer work, as he has a real full time job as well

Doug

 

[onpier55]

O2 sensers. Which one goes on passenger side and which one goes on drivers side. Thanks in advance.

 

[millerpz]

The drivers side O2 is part of the main harness, while the pass side goes into the transmission connector (but you will likely remove and shorten so it too is only off of the main harness). The rear O2's also go through the transmission connector but get removed. Front are green (96-98) or Grey (99-01), while the rear are always blue. When the harness is laid out its a lot more obvious.

 

[Shelbyluvv]

Hey all, new guy here. I am in the process of swapping a 48 Ford F1 onto a 1998 Explorer 5.0, AWD chassis. In my research I was lead to this forum. Great info and tech advice. Thanks for having me.

 

[Rocko1012]

EFI Eplorer information needed.

Can stock Bronco Gauge Cluster be used? Where can i get diagram/information of exactly needs to be in each harness? (ENG/Firewall) HARNESSES. OBII connecter needed? CEL in dash? Will be running a 98 Explorer EFI, Stock Tank on 1977, Manual Steering converted to power. I am missing ECM, Can a 2001 ECM work with 98 Harness?
All comments and information is appreciated.

Ron

 

[sykanr0ng]

1. Can stock Bronco Gauge Cluster be used?
2. CEL in dash?
3. I am missing ECM, Can a 2001 ECM work with 98 Harness?
All comments and information is appreciated.

Ron

1. Yes, the speedo reads off the transfer case, need to use Bronco senders for the other gauges.
2. It has been done in the dash, and in the gauge cluster also.
3. There were changes every year, so it is much easier to keep the year of the harness and PCM the same.

 

[904Bronco]

1. Yes, the speedo reads off the transfer case, need to use Bronco senders for the other gauges.
2. It has been done in the dash, and in the gauge cluster also.
3. There were changes every year, so it is much easier to keep the year of the harness and PCM the same.

98 Explorer should still have a return fuel line
01 does not

Best to go with Sykanr0ng's recommendations of ECU and Harness being from the same year.

 

[millerpz]

It may be possible, but as others have said, I would avoid the hassle.

For a '98 harness, you would want a PCM code of: NRT1, EDS1, or PCC1. The '98 is a desirable year as its already setup for the most improved version of the 4r70w used behind a 5.0l and it still retains the return fuel system.

 

[sykanr0ng]

It may be possible, but as others have said, I would avoid the hassle.

For a '98 harness, you would want a PCM code of: NRT1, EDS1, or PCC1. The '98 is a desirable year as its already setup for the most improved version of the 4r70w used behind a 5.0l and it still retains the return fuel system.

Just did a search on eBay:
PCC1: one for $25 free shipping and one for $16.03 free shipping.

I would buy both, it is good to have a spare.

 

[904Bronco]

Just did a search on eBay:
PCC1: one for $25 free shipping and one for $16.03 free shipping.

I would buy both, it is good to have a spare.

I agree.

These are going to go the way of the Mustang ECU, which are going for $200-$300 now. Good to have spares... Seems like it is the 1st thing that is pulled out of a Explorer/Mountaineer now at the local PnP

 

[toddz69]

X3 on the spare ECMs. I am having EFIGuy do a harness for me now and also doing a spare ECU for me at the time. It probably wouldn't hurt to get 2-3 more done at the same time to have a lot of spares. I'm thankful my A9P is still working well in my original swap and I have a spare for it as well.

Todd Z.

 

[garberz]

I’ve done a few of the now. I’ve always had Garry do the PCM’s two at a time.

Mark

 

[Rocko1012]

Look at attached pictures and let me know if we need anything else. I also have complete engine Harness, still on engine at moment. Running Manual 3speed stock. Would like to keep original guage setup. I have looked at EFI GUY videos extensively, Need tpo know exactly what needs to be deleted from harnesses, I like to understand the process, first modify engine harness as needed, second firewall harness is set up to run power (relays and such)? 98 Explorer,

 

[millerpz]

Pic 1 & 3 look to be good for the body harness. Pic 2 looks to be the alternator harness this goes along with the engine harness. Most of what's there on the body harness will get removed. You mainly need the wiring that runs from the big fuse box to the c115 plug (this plug is the main connection to the engine harness). Most of the rest gets removed. To complete a body harness, you also want the wiring pig tail's and plugs for the OBD2 sensor (under driver dash) and the inertia switch (pass kick panel), but many other ford's of that era can and will interchange.

If you have the engine harness, that's good. If you are running the 4r70w, then you would want it's harness too. These connect to each other in another large square plug at the transmission (looks alot like the c115 plug).

Those are the 3 harness assembly's you need: engine (including alt), body and possibly Trans (only needed if using 4r70w).

Over all, the most extensive of the modifications will occur in the body harness. The engine and Trans harnesses are more minor.

 

[EFI Guy]

millerpz gave a great answer, but I'll expand on it just a bit.

If you are not running a 4r70w and you don't have the transmission harness, you will need to find a green o2 sensor plug to add to your engine harness.

It's also a good idea to run a VSS with a manual transmission, but it's not 100% required. The OSS plug from a transmission harness can be used for it.

The rest of the wiring going to the transmission can be removed.

The engine/transmission harnesses together don't have to be modified at all, but you will be left with a bunch of extra plugs and wiring if you don't. All that really happens to the engine harness is moving an o2 sensor plug from the transmission harness to the engine harness, the rest is just removing unused wiring.

Post #2 gives PCM pin numbers of every circuit that can be removed.

 

[Papa Turdly]

Sorry for the following questions, but I hate wiring and want to make sure I understand what I am doing before I continue on. I have watched the video #2 for the firewall harness a few times (through the explanation of the wires about 41 minutes) and have questions on the following wires on the C115 for a ‘97 harness with 4r70w behind it.

The pink wire that is pin #13
The blue with yellow stripe wire that is pin #20
The pink with yellow stripe wire that is pin #30
The red with gray stripe wire that is pin #31
And the two black with gray stripe grounds in pin #34 & #42 go inside the cab or towards the relay side?

Thanks again, I appreciate any help/guidance!

 

[EFI Guy]

I don't like to use c115 pin numbers due to variation. But I'm guessing your pink wire has an orange stripe and goes to pin 33 on the PCM? If so, that is VSS-. If you're keeping VSS then wire that to its own dedicated ground. I usually recommend removing VSS and tuning it out with a 4r70w unless 2wd only. I recommend keeping it with a manual trans.

Pink with yellow gets removed from both sides of the harness unless you are going to wire in the AC WOT cut out relay. I always remove it but I posted diagrams for how to use it a few pages back.

Blue/yellow gets removed from the firewall harness. If you are not using a 4r70w then it gets removed from the engine harness too.

I'm not aware of a red/grey, but if you meant grey/red, remove it from the firewall side, leave it in the engine harness.

I run the other ground wires near the relay pack and ground them under the hood.

 

[Papa Turdly]

Alrighty, I think I got a little ahead of myself when removing the rear o2 sensors and relocating the front o2 from the 4r70w harness. What pins from the pcm connector control the “passenger” side front o2 sensor?

On a side note, if I failed to grab the inertia switch and obd2 port from my ‘97 Mercury Mountaineer donor, can I buy “new” ones that will work, or am I better off going to the junkyard and finding some to remove?

Thank you again for the great videos and tech, I would have had ZERO interest in keeping the distruborless and obd2 set up when swapping into my Comanche.

 

[toddz69]

On a side note, if I failed to grab the inertia switch and obd2 port from my ‘97 Mercury Mountaineer donor, can I buy “new” ones that will work, or am I better off going to the junkyard and finding some to remove?

With the plentiful nature of both of those items at the u-jerk-it's, I wouldn't buy anything new. Besides, those type of items sometimes just fall into my pockets while I'm walking around in the yards too .

Todd Z.

 

[Papa Turdly]

With the plentiful nature of both of those items at the u-jerk-it's, I wouldn't buy anything new. Besides, those type of items sometimes just fall into my pockets while I'm walking around in the yards too .

Todd Z.

We don’t have many of the u-pulls around, so I will have to see what I can come up with from the local junk yards.

After further de-pinning of the pcm connector, I have determined (hopefully correct) that the following wires/pins are for the passenger side front o2 sensor:

PCM # 60 is grayish w/blue
PCM # 93 is red w/white
PCM # 91 is grey with pink or red (this wire is spliced into 4)
The last wire is blue w/pink and goes to the C115, which I assume goes to the o2 heater relay? This wire is also splice into 4 ends, 1 or which is i the driver side o2 and the other 3 went to the transmission connector.

Am I close? Lol