Hello I have been working on a project where I have become lost I have a 2003 Nissan Altima that had received a 2006 ecm and engine wiring harness. Thinking that this would be plug and play I didn't do much prep work and just slapped the harness on and went from there. I had to switch a connector where the harness goes into the body harness and I have tuning software to turn off the immobilizer system and I was able to get the fuel pump to turn on with key as well as get the car to crank but it won't fire I have no injector pulse and no spark. I spoke with a shop in Georgia called 2jr racing and they have successfully done this swap with a different car. I was told that the issue is where the harness connects into the other harnesses that make up the electrical system. So I pulled the 2006 harness off and plan to put the 2003 harness back on but adding in the changes for the 2006 ecm to function (different o2 sensor, MAF sensor, and power steering pressure sensor) as well as the 2006 ecm connector. I have already labeled all of the wires on the 2003 connector and I am ready to take the pins out and move them into the 2006 connector but I don't want to make this issue worse the car had been down for a year and I want to drive my creation again.

 

And what are we suposed to help you with exactly?

 

Any useful gidiance. Am I thinking about this the right way. Re pinning the existing 2003 harness to the 06 connector is just pull pins out and move them? Can I just let the changes connects to the connector?

 

Okay, I see where you're going now. I've put odd engine and transmission combinations in vehicles that never were factory options before so I can relate rather well.

Yes if you have correct wiring diagrams for both harnesses and everything on the engines and anything else they connected to you should be able to swap the connector ends as you are thinking.
I don't know what type of connector system your vehicle has but if its the more common pin and socket type if you have the right tool to release the pins and sockets from the bodies they are pretty easy to pop each wire and relating pin or socket out of one connector body and plug them back into the other without damaging anything.

The only other issue I can think of is if the two engines and their related sensors and control systems are not close enough to be directly compatible though just programing changes alone you may run into a problem there. If so then you would also have to get the correct matching sensors from the other vehicle that matches your ECU.

 

The engines are exactly the same the only reason for the swap is to tune the car. The 2003 computer is not able to be tuned but the 2006 is. The car has also received a manual trans. I was thinking about moving the trans connectors that aren't the same which I believe is only one I will post my references.

 

Here is the link to the wiring section of the fsm for the 2003 Altima
https://www.dropbox.com/s/uyjr7ivsooenieh/2003 wiring.pdf?dl=0
Here is the link to the wiring section of the fsm for the 2006 Altima
https://www.dropbox.com/s/a9pr1thvbnd9q85/2006 wiring.pdf?dl=0

I started stripping the MAF wiring out of the 2006 harness yesterday I did see that there is a splice shared with other wires do I need to take everything with that splice?

 

There are 1306 pages to the 2006 wiring manual. Can you help narrow the search down? Maybe snip the portion of the diagram about which you have a question.

As for a splice to other wires, that depends on what the other wires do. For example, in my Ford Fusion, the signal common ("SIGRTN") serves four sensors -- A/C high pressure, MAF/IAT, fuel tank pressure, and a rear vent. Three of the four are probably important. Then, you have to consider downstream effects of disconnecting any one of the returns. For example, if the A/C return is not attached, you get an A/C pressure error at the ECM/PCM (probably reads "high"). That will lead to the electric radiator fan going full speed all of the time.

To give an accurate answer to your question, one would need to know the exact circuit number for those "spliced" wires and then research all of the circuits/sensors involved.

John

 

I would suggest the nissan forums. Ask them the same questions and find out others responses. Aftermarket ecm's and ignition systems may be an option. Or return to the racing shop and actually see what was done. From experience : if this will be a daily driver the check engine light will always be lit. I have swapped them in my personal vehicles and ran them with ac pressure sensors and tcs's wired in the harness and duct taped to any safe place I could!

 

The harness is out of a car with the same body code, nissan just made a couple small changes in the wiring I abb currently making a custom harness using the 2003 harness as a base and adding the necessary changes from the 2006 (maf, A/F, and the power steering pressure sensor) other then that nothing changed besides where the harness connects into the other harnesses. By using the 2003 as a base I'm able to swap the ecu connectors and the car should start. Hopefully I will have the connectors swapped sometime this week.

 

i went back in my records and found the recall list for the altima then searched it on the web. should have gone to the net first . the very first listed recall is the cps. on a 2006 2.5l engine but these same cps's were used in almost every size engine in all countries through different years,just the part number on the outside changes. i know myself as an engine is swinging in the air- pushing and pulling occurs and the wiring on the engine is sometimes touched. the wires are brittle at the sensors leading into the block and like stated in the recall the cps heat fatigue and develop fractures that lead to open circuit leads and engine shuts off.
now the tcs is located normally in or around the intake air filter. if this is not connected the during attempts to start the engine it may seem to be dragging acting like a low battery. truth is the timing by either one of these sensors can change up to 50 degrees btdc. also raising the compression and blowing head gaskets. i've repaired a 1000 of 'em. failed cps led to damage.
also mid year next model year the wires may have the same colors/ tracers but changes are made in which component it powers. in the service manual listings for vin numbers and changes made and which of the jpanholt noted pages determine which wiring layout is the correct one. whew i hope i got all my leds, leads correct. just really attempting to help. a rat in the dash can cause marvels of problems!

 

I am very well aware of that issue this id's not my first time building this car I have had the engine in and out numerous times. I'm actually a mechanic and have seen a few failures of the crank and cam sensors they all caused a symptom similar to a miss snd they fail because they get oil through the sensor itself. As far as the condition of the wiring that's not an issue as much as the older designed sensors. I didn't have to replace my cam and crank until the car was at around 100,000 and on its third engine. I have spent over a year and a half putting the current build together with a 02 six speed out of a sentra build engine lightened fly wheel and a list of many mods. I'm not sure what I'm supposed to research.

 

Ec-106 is the start of the 2006 wiring diagrams. I am only concerned with the qr25de (4 cylinder) version of the car.
EC-96 is the start of the 2003 wiring diagrams again I am only concerned about the qr25de version.

 

Take both harnesses and lay thwm side by side. Start at the body connector and compare pin by pin. Move the circuits you need to. Mark off on your diagram which ones are complete. Do the same for ecm connectors. Follow this and you will have all the proper connections. When you are done and before you fire it up, check for codes. Fix as necessary.

 

Take both harnesses and lay thwm side by side. Start at the body connector and compare pin by pin. Move the circuits you need to. Mark off on your diagram which ones are complete. Do the same for ecm connectors. Follow this and you will have all the proper connections. When you are done and before you fire it up, check for codes. Fix as necessary.

Exact method I chose

 

Have you got this thing figured out?

 

I'm still working on getting things right. The ecm will not power on unless I apply ground to the ecm relay showing power to flow to the ecm one it is powered on I have codes for can communication
And I still have a no start condition. I do however have 12v at the coils as well as the injectors but no signal coming from the ecm to create spark and injector pulse. The immobilizer system is disabled via an Uprev supplied ROM. I believe the no start condition and lack of power until ground is applied is due to the can system not being satisfied. Any thoughts.

 

I'm still working on getting things right. The ecm will not power on unless I apply ground to the ecm relay showing power to flow to the ecm one it is powered on I have codes for can communication
And I still have a no start condition. I do however have 12v at the coils as well as the injectors but no signal coming from the ecm to create spark and injector pulse. The immobilizer system is disabled via an Uprev supplied ROM. I believe the no start condition and lack of power until ground is applied is due to the can system not being satisfied. Any thoughts.

Can you list all Pxxxx and Uxxxx codes?

Its possible you also will need to reflash this new ECM with a J2534 module. Or at leas tell it the VIN. I can only give the walk through using a Nissan consult3 factory scan tool. Ive personally never done it.

The diagram for the ECM-Main relay shows that the ECM needs to see 12V from the ignition switch through a 10A fuse labeled "1" (Possibly in the dash/instrument panel fuse block). From there its a red wire that travels down to pin 100 of the ECM labeled IGNSW. I would imagine the ECM needs to know a human requests the car turn on and uses the IGNSW circuit for that. Can you verify this?
-Jason

 

That was my thought as well I have checked the ignition wire on 100 and I have 12 volts. I will double check tomorrow morning when I get home from work along with the code.

 

The only other thing that I can think of is the CAN code is related to immobilizer system and since the ecm isn't seeing the module at all and not allowing anything to work?

 

This info may also be useful
-Jason




The immobilizer function of the NVIS (NATS) consists of the following:

• NATS ignition key
• NATS antenna amp. located in the ignition key cylinder
• Body control module (BCM)
• Engine control module (ECM)
• Security indicator lamp

NOTE: The communication between ECM and BCM uses the CAN communication system.

ECM Re-communicating Function
The following procedure can automatically perform re-communication of ECM and BCM, but only when the ECM has been replaced with a new one which has never been energized on-board.
(In this step, initialization procedure by CONSULT-II is not necessary.)

NOTE:

• When registering new Key IDs or replacing the ECM other than brand new, refer to CONSULT-II Operation Manual NATS-IVIS/NVIS.
• If multiple keys are attached to the key holder, separate them before work.
• Distinguish keys with unregistered key ID from those with registered ID.

1. Install ECM.
2. Using a registered key (*1), turn ignition switch to ON.

*1: To perform this step, use the key that has been used before performing ECM replacement.

1. Maintain ignition switch in ON position for at least 5 seconds .
2. Turn ignition switch to OFF.
3. Start engine. If engine can be started, procedure is completed.