Alchem1st

iTrader: (2)

Hey guys, I've just finished swapping a Lancer ECU into my Mirage flashed with Tephra v7; and what a difference it's made to the idle quality and just general operation!
So here's the how to on swapping these ECU's into a 97-02 manual transmission Mirage or an Evo 4-6.


First, this is the list of known differences between an Evo 5 ECU pinout and an Evo 8 ECU pinout:

Pin 8 and 22 are reversed between Evo 5 and Evo 8. (doesn't apply due to using a Lancer ECU)
Pin 9 Purge solenoid doesn't exist on Evo 5
Pin 20 is blank on Evo 8. Rad/AC fan high on Evo 5.
Pin 24 AC control unit on Evo 8. Blank on Evo 5.
Pin 32 AC fan relay high on Evo 8. Blank on Evo 5.
Pin 34 AC fan relay low on Evo 8. Blank on Evo 5.
Pin 35 IC spray on Evo 8. Blank on Evo 5. (possibly wire this in to the IC sprayer motor)
Pin 40 blank on Evo 8. Alarm W/L on Evo 5.
Pin 43 clutch swith on Evo 8. Blank on Evo 5. (check to see if this wire exists. should be lg in color)
Pin 44 IC spray auto on Evo 8. Blank on Evo 5. (again, possibly wire this up)
Pin 51 immobiliser on Evo 8. Blank on Evo 5. (will be disabled)
Pin 54 rear o2 heater on Evo 8. Blank on Evo 5. (will be disabled)
Pin 55 IC spray relay on Evo 8. Blank on Evo 5. (again, possibly wire this up)
Pin 56 blank on Evo 8. Diagnostic port on Evo 5.
Pin 75 rear o2 on Evo 8. Blank on Evo 5.
Pin 87 ACD/AYC signal on Evo 8. Idle switch on Evo 5.
Pin 91 IC spray manual on Evo 8. Ground on Evo 5. (I think this is where the ic sprayer switch goes. Not sure if it's a switched ground or if it needs to receive power to trigger)



So here's what I did to make everything work on my car:

Cut ECU pin 21 in the wiring harness and cap off the harness side. (Alternatively, unpin the connector and heatshrink the original wire to keep from having to cut your harness.
Then pin in a wire cut from another ECU plug. This saves you from having a cut up harness and preserves your original wiring if you ever wanted to go back to stock for some reason.)
From the ECU side, pin 21 now needs to run to the engine bay to the fan control module. It's the fan trigger wire. You have to get a fan control module and the wiring pigtails from an
02-07 Lancer. (Evo 7-9's and some Outlanders also have this module) Most of the threads discussing Evo 7/8 ECU upgrades in Evo 4-6's say to swap pin 20 to pin 32 and pin 21 to pin 34.
This doesn't actually work to trigger the fans. (at least it doesn't work for me) The best way to make your radiator fans work is to add the Evo 7-9 fan controller. More on this in a moment.

Remove pin 20 and heatshrink. (I didn't want to cut this wiring, so I unpinned the connector and heatshrunk it.)
Remove pin 32 and heatshrink. (I didn't want to cut this wiring, so I unpinned the connector and heatshrunk it.)
Remove pin 34 and heatshrink. (I didn't want to cut this wiring, so I unpinned the connector and heatshrunk it.)
Remove pin 87 and heatshrink. (I didn't want to cut this wiring, so I unpinned the connector and heatshrunk it.)
Remove pin 91 and heatshrink. (I didn't want to cut this wiring, so I unpinned the connector and heatshrunk it.)


If using an Evo 7/8 ECU, swap pins 8 and 22. If you don't do this your car won't start. If you're using a Lancer ECU with an Evo 8 map DO NOT switch pins 8 and 22 or your car won't start.
Pin 8 is your fuel pump relay on a Mirage or Evo 4-6 and Pin 22 is your AC compressor relay. On an Evo 7-9 these pins are reversed for some reason, but on a Lancer they are the same as
a Mirage.


Ok! That should be all you need to do on the ECU wiring side of things! Now we need to add the fan control module we talked about earlier. 5G Mirage's and Evo 4-6's use a 12V trigger from pin
20 on the ECU to trigger the AC fan and the radiator fan. When the ECU wants the fans to turn on it energizes this wire and the fans come on. Evo 4-6's also have a radiator fan low mode
from Pin 21, but we don't have this to worry about. It's the reason we capped off this pin earlier though. So you need to grab the fan controller and the wiring pigtails from an 02-07 Lancer.
(Again, Evo 7-9's and some Outlanders also have this module) The fan control module has three plugs on it: two fan outputs and one input. The large input connector has three pins on it.
Black is a chassis ground. Ground this wherever is most convenient. Blue is a 12V source straight from the battery. (Stock it's hooked to a fusible link, but as I connected mine straight to
the battery terminal I added a fuse holder just to be safe.) The middle and much smaller 18Ga wire is the control wire. It needs to connect up to Pin 21 on the ECU. (You added a wire there
earlier right?) The fan control module needs to be mounted in a position similar to how it was on the car you removed it from. You can just get the fan from your donor car as well to make
mounting easier, but if you're turbo then I recommend getting an Evo 7-9 fan. The Evo fan has nine blades vs the Lancer fan that only has four. You may experience overheating with the Lancer
fan; so be aware of the difference. The metal side of the fan control module contains a thermometer that sends temperature information back to your shiny new ECU, so it needs to be in a
position to get an accurate temperature reading. Using a Lancer or Evo fan also has the benefit of not needing a rewire since your Mirage/Evo 4-6 fan has a different connector. I'm using an Evo 8 fan
in my build but maintaining the Evo 4 fan that mounts on the front of the radiator support. If you go the same route as me you'll need to cut the AC fan harness that came with your fan control
module and splice on a connector that will work for your AC fan. (Again, it's a different connector. That's the only reason you need to do this. It's only two wires, so it's pretty simple) If you're
non turbo and have plenty of room in your engine bay, just use both fans from the Lancer and you'll be fine.


Once you have the two fans wired up and the fan control module input wired up you should be done! You'll need tuning to make your car run properly on Tephra as it's stock coding is meant for
a bone stock Evo 7-9. (depending on which rom you selected) I have some trouble with P0340 and P0335 CEL's on the 94170715 Tephra rom (for a USDM VIII), but switching to 96530706 Tephra rom
(for an AUDM Evo VIII) fixed those two codes. I also was getting P0443 Evaporative Emission Control System Purge Control Valve Circuit and P0090 Fuel Pressure Solenoid Circuit codes which are both
related to my IV engine not having EGR equipement. If you don't have EGR equipment on the engine you're using, you follow the same method as the Evo 8/9 to remove those two codes. I also was
getting a P0243 Turbocharger Wastegate Solenoid 1 Circuit code, but it went away on it's own. (Probably due to me having an aftermarket 3 port boost controller) Your mileage on that code may
vary if you're using one of these ECU's on a non turbo engine. You also need to remember to disable the immobilizer. Once I got these all taken care of the car runs perfect! That should be all you
need to do! Hope you guys found this how to useful! Thanks to Brandon Bushrod and Edwin Fumero (Mirageforums members) for helping me with troubleshooting! Something else to note is that if you
have an 01-02 Mirage Automatic, you don't need to do this swap as you already have an SH2 ECU that is basically the same as an Evo 9 ECU, and should be able to be flashed with an Evo 9 rom from
what I understand. You'll need to verify this yourself though or you risk bricking your ECU. Hope this helps some of you guys out with your swaps!

94AWDcoupe

iTrader: (125)

good post

Rovin Raj

Good post. But unfortunately i did not get the info i wanted. After swapping ecu. (afaik ecu pins are all same) my fans run 24/7 when i start the car. It does not off. But if i on my AC the fan goes off. 😂 what should i modify.

Alchem1st

iTrader: (2)

Did you install the fan control module or are you trying to use the later SH2 ECU without it? You have to have it for the fans to work properly.

Rovin Raj

i am trying to run it without the fan controller. Maybe edit in ecu flash or something. I sent you a pm.

Alchem1st

iTrader: (2)

Ah yeah I dunno man. I don't see how it would work since that output wire is a data signal and not a 12V on and off like the older style ECU uses. The fan controller itself has two fan outputs and on main connector with three wires. The heavy gauge wires are power and ground, and the small wire in between them is the data signal in from the ECU and that's about it! Pretty easy to wire.

Tim M

Wow...that is a detailed how to! Thanks.

black_out

9/10 times when I have these come in stuck on it's the fan control module mounted on the fan. I'd take a scan tool and look at coolant temp and check for codes though. I've only had one with a shorted temp sensor reading high temps keeping it on.