whlimi

iTrader: (11)

I was running a cali spec ECM in my 3.5 swapped 99. I had 14 codes, most of them emissions related (damn cali spec) and TCM codes (running SSV4).

Got myself a 95 5spd ECM from the junk yard and decided I would take the plunge and swap it into my 99. After an EU and SSV4 install, I'm happy to say that it was a fairly easy modifaction and took about an hour and a half most of which was spend tracing wires to double check the 99 FSM.

The advantages are obvious. No more codes apart from EGR (will solve this) and the P1320 because of the EU. This mod is great for those 3.5 swapped 99s looking to erase some codes. I can finally replace my broken keys without paying for the reprogramming and if I ever choose to do so, I can run a JWT or Technosquare ECM without paying the extra bucks for a 99.


Since I'm running the SSV4, I did not pay any attention to the automatic transmission communication wires running to the ECM. You might have to make a few more changes to get it to work with an auto.

This writeup will work for a 5spd.

Here's what you need to do:

- Disconnect the negative terminal of your battery
- Pull out the ECM and disconnect the harness. Familiarize yourself with the orientation of the harness and the pinout sheet you're referring to.
- Pry the white locking tabs up to unlock the pins. I used a small flat head screwdriver.
- I removed the Pins by yanking on the wire a la Pmohr. No wires or pins were damaged this way. (Make sure the white tab is unlocked or you will damage the wire/pin)

Pin swap:

Fuel Pump Relay - switch B/P wire from 117 to 11. What you need to know about this pin is that it's larger than the socket in location 11. It's the only pin that was not a direct swap. You will either need to acquire a smaller pin from another harness or use a redundant one from the 99 ECM. I used the NATS pin NATS is pin 17 (Orange wire). Remove the NATS pin and relocate it to 11. Cut the NATS Orange wire leaving enough wire so that you can splice into it. Remove 117 B/P and splice it into the NATS wire now located 11. You have successfully moved 117 to 11.

PNP Switch - Wire colour is G/W Manual Transmission or R/G Automatic Transmission located at 27. We need to swap it over to 22.

CKPS REF and CMPS - This was super easy. All you need to do is swap the locations between the two sensor's pinout locations. Originally on the 99, CKPS is at 46 and 47 and CMPS is at 44 and 48. We need to swap it so that CKPS is at 44 and 48 and CMPS is at 46 and 47.

Rear O2 - Not necessary but will get rid of the code. Red wire Located at 107. You need to move it to 105.

Reconnect harness to 95 ECM. (I think you can run 95-98 but I'm not positive and will let the Guru's chime in)

Swap completed

During the course of your modification, you might be a bit overwhelmed by how tightly packed all the wires are. If you cant get to a wire, trace it down, locate it near the bottom of the harness and you can pull it up and yank it from there. When inserting the pins, make sure it's all the way in. Most of the time once it's in, it will resist being pulled out again.

Double check everything and reconnect the negative terminal to the battery.

Your security light will remain on when the car is running but will not effect anything. You will have an EGR code.

I suggest you verify pinout locations yourself with a multimeter and not solely rely on this writeup. Better safe than sorry.

****** I will not be held responsible for any damage caused to your car due to preforming this modification. You do so at your own risk. *****

Juscruzn

iTrader: (3)

Again, THANKS!!!

What's a EU?

Also I PM'ed you to ask another question...

whlimi

iTrader: (11)

EU=Emanage Ultimate (Piggyback)

Juscruzn

iTrader: (3)

So the FSM is wrong with only one of the pins you moved?

The '99 diagram shows pin 27 for PNP switch, sould be pin 22, right?

whlimi

iTrader: (11)

Are you asking if you only need to move one pin?

The PNP is located at pin 27 on a 99. The 99 FSM is correct when referring to this. In the 95 FSM, PNP is located at pin 22. So we need to move it from 27 to 22.

pmohr

iTrader: (26)

Awesome.

Looks like I'll be adding a '99 ECU pinout chart to my sticky in AM after all.

Juscruzn

iTrader: (3)

Never mind. Needed to zoom in on the .pdf

What about the rumor that the '99 FSM is incorrect?

pmohr

iTrader: (26)

Did you compare his pinouts to the FSM?

He states that the CKPS REF is on pins 46/47 and CPS is 44/48, the FSM states the opposite.

whlimi

iTrader: (11)

It's the way things are worded. For example pins 44 and 48 are for the CKPS Phase....no such sensor exists. And 46 and 47 are for CMPS REF. Again no such sensor. Its supposed to say CKPS REF at 46 and 47 and CMPS Phase at 44 and 48. Swap the pins around and it's the same as a 95-98.

Another way to think of it is if you took the signal wire form the CKPS REF (under crank pulley) and connected it to the CMPS sensor on the timing cover and took the CMPS signal wire and connected it to the CKPS REF sensor. Same result as switching pin locations.

Juscruzn

iTrader: (3)

Very good explaination! Thanks. It all makes sense now!

whlimi

iTrader: (11)

Looking at the FSM, it's seems possible to do this mod in an auto as well. Just requires a lot more work.
98-99 Autos have one communication line (LAN) that runs to the ECM. 95-97 autos have several communication lines. (Off the top of my head, check FSM to verify years)

I do not know how a 99 TCM will react when it cant communicate with the ECM. If the TCM is able to control the transmission without the communication line then this will not be necessary. If not, then the following measures might help:

- What you need to do is find a 95-97 TCM along with the TCM harness pigtail.
- You will need to look in the AT section of a 95-97 FSM and refer to the TCM pinout. From there you will have to patch up the 99 TCM harness wires to the 95-97 pigtail that you acquired with the 95-97 TCM. (These will be all the wires responsible for for controlling the TCM such as shift/lockup solenoids, revolution sensor, tranny fluid temp sensor, TPS, power, ground, etc...)
- You will need several wires with pins to run from the 95-97 pigtail to the newly swapped ECM. These will be the TCM communication wires. They will have to be pinned in the ECM harness in the appropriate locations (Refer to EC section of 95-97 FSM for TCM communication wires pinout locations)

This has not been tested and is based on theory. I would have loved to test this out but it's just not feasible for me to go out and gather all the parts when I wont be using it anyway.

ls1forlife

Glad everything worked for you, does anyone know about swapping a 5spd into a auto 95 max? When theheels turn it idles high(around 1200-2000 depending). I dont have a 5spd ecu but i unplugged the tcm and it didnt fix anything. Is it just trying to keep the torque converter spinning?

pmohr

iTrader: (26)

Either get a 5MT ECU or learn to live with the driveability quirks you'll have with a 4AT ECU. No way around it, really.

ls1forlife

thanks a lot really appreciate it. Does the year matter much? or will a OBDII ecu work? Its really hard to find a 95' 5 spd ecu around my location

Kevlo911

iTrader: (36)

Good work man!!!!

whlimi

iTrader: (11)

All 4th Gens are OBDII. The next best thing to a 95 5spd would be a 95 auto in terms of getting rid of emissions related codes but you will have to deal with the way the auto ECM controls the IACV, and the SES light for the missing TCM. I believe the 96 will throw a code for the fuel pump but if you can live with an SES light and pass emissions in your area then a 96 5 spd is also an option.

ls1forlife

Mine is a 1995 nissan maxima, it is obdI. It has its original ECU with the TCM unplugged. I dont care about the SES or the CEL, i just want the idle to stay at 700 rpm. it will raise the idle soon as the wheel speed sensors tell the ecu its moving. Im guessing to either run the trans pump or keep the converter spinning? Either way, the auto is long gone, and i want to be able to drive it with out the hasle

whlimi

iTrader: (11)

Your 95 max is OBDII. The connector is located on the passenger side next to the ECM and not under the dash next to the fuse box.
As far as dealing with the idle issues of the auto ECM, you can try throwing in a 96 5sd since you dont mind the check engine light.

ls1forlife

Oh great thank you! I have another connection where the obd port in on normal obdII cars? i just thought that was a obdI port. So any 4th gen 5spd ECU will work? Local yards just dont have them just auto

pmohr

iTrader: (26)

...no. Had you searched, you would've found this:


There isn't any port where the 'normal cars' have one, but there is a CONSULT connector in the fuse box, if that's what you're referring to.

No, not any 4th gen 5MT ECU. Obviously the '99s won't work, everything else will, but some will throw a CEL.

ls1forlife

thanks a lot for the help. Ill try and find a 95 5spd ecu, but doubt ill even find a 5spd ecu for any year..

Juscruzn

iTrader: (3)

Junk yard!

Mazda Nissan Heaven
(817) 563-2277
6711 Oak Crest Dr E, Fort Worth, TX 76140

Has them for $90, not sure if they ship.

Or car-parts.com

ls1forlife

thanks a million! im being told its my ECM? always thought they were 1 in the same?

adriena

iTrader: (6)

I have a vq35 swap on my 99 and a 96 ecu with a 99 harness with this swap. but I'm pretty sure my harness may be bad. Would I just be able to buy a 95 to 98 engine harness plug that right up to everything connect it to my 96 ecu in my 99 and have it run without switching any pins, or would it be best to find another 99 engine harness and do this swap? already had this done for me because I was not comfortable dealing with electrical, but recently there's no power to my ECU, well at least I think so since my CEL light will not illuminate, the ECU will not allow a scan tool to read it, it just says error, just trying to figure out the best solution to getting my car started while still thinking about performance down the road.

CS_AR

Thanks for the information. I just bought a 99 I30 automatic with a bad ECM. I would like to convert it to use a 95, 96, or 97, ECM, TCM, and EGR (if needed) setup. There are many 97 models in the salvage yards for pulling the parts.

We have a 95 Maxima 5-spd that is a lot of fun.

MAXIMA_STYLE

iTrader: (21)

Not to be a noob and bump an old thread but this is vital information for many people so BUMP,this should be stickied,forgive me if it is,as i havent seen it there....

Maximeltman

iTrader: (11)

Thanks!

max1008

Wow I've searched concerning ecm and this never came up. Have many tried this with their 99?

MAXIMA_STYLE

iTrader: (21)

No idea how many have done this swap, i got a 99 se-l cali spec car with fed spec engine and i got a fed spec 97 5 pd ecu sitting waiting for me to be brave enough to ripped some wiring apart....but im sure it cant be too hard...

deloa84

iTrader: (5)

I am doing a late bump but I am venturing to do this ecm swap today. I actually got lucky and found nice 95 5 speed ecm I am about to put in my 3.5 swap.

95crackedhead

Bump for a sticky.

Anyone know if trim level matters? I have a '99 SE 5 speed and dont want to deal with reprogramming the NAT$ security. I'm currently locked out of starting my car.

ECM swap seems much easier right now.

deloa84

iTrader: (5)

Nope don't matter. Mine is a 99 SE 5speed as well... As long as you follow this writeup you will be ok. Read my thread on how to get rid of the EGR code to pass emissions and you're good to go!!

darrick

Praise the Lord !!!!!!!! this is great news.

deloa84

iTrader: (5)

Here is my thread. Makes a great addition to this writeup... EER soon to be sticky??
http://forums.maxima.org/4th-generat...-swap-yay.html

95crackedhead

My '99 is a cali spec, so should I get a '95 cali spec ECU or shouldn't it matter?

deloa84

iTrader: (5)

Shouldn't matter. Looking at the FSM and wiring diagram for the ecu on a 95 they are the same on a cali/fed spec. The only difference is the design of the EVAP and that is it! As time goes on the differences between Cali and Fed change drastically but not for the 95 ecu. A good example is the Cali spec 99 which has 4 O2 sensors versus 2, a stepper design EGR, swirl control valves, precats... etc.

MAXIMA_STYLE

iTrader: (21)

You knkw ive had a fed spec ecu sitting in my hall fpr a year now... read this thread numerous time and still nervous about jumping into it....lol

95crackedhead

Already got d/l the 95 FSM. Thanks for the insight, delo. Will post back with an update on how it goes.

deloa84

iTrader: (5)

I know exactly what you mean. The more you read it the more nerve racking it is. I had no choice but to just do it since I was immobilized by the dam NATS and I was sick of it. Added plus is easier emissions. Once you get into it was not that bad but I had my buddy help me. Have someone give you a hand even if its just reading the instruction or their just there for moral support, it really helps. They say two heads are better than one. Found that to be true... lol

95crackedhead

Just wanted to let everyone know that I did this with great success. The car started the first time, and amazingly I have no CEL anymore. I even have the knock sensor unplugged with no codes.

I scanned the computer with an Actron code scanner and confirmed there are no stored codes.

I used a '95 Auto ECM that I picked up for cheap in the junkyard, even though my car is a stick. Still works fine. No codes for EGR, O2 or anything. I also don't know if the new ECM is Cali or Fed, but as one of the posters above said, it doesn't seem to matter. This is confirmed.

I haven't driven the car yet, because it is still misfiring, (suspect leaky fuel injector), but I did turn the steering wheel back and forth a few times. The idle does come up to around 1300 rpms, momentarily, but does settle back down a couple seconds later.

My original purpose was to bypass the NATS security and avoid a tow and a $180 reprogramming fee from the dealer. I was testing the fuel system and passed the 3 strikes and you're out deal with leaving the door locked when trying to start the car. Local locksmiths wanted upwards of $250 just to look at it. Insane. I recommend this to anybody who has a pick 'n pull type junkyard nearby and is in the same situation.