4G94 MPI SOHC Pajero owners ECU Fix

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Jivonski's picture
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Ok so its not really a fix for the ecu but its better than having to be stuck with a non working Pajero or stuck staring at the ridiculous price for a replacement ECU that only seems to be located in Russia. Read to the end as to another route you may choose apart from what i did. 



Short History:

I purchased a 2003 Pajero iO H77W Automatic with a 4G94 MPI SOHC engine that wasnt starting. After extensive checks it came to being a badignition driver on the ECU that wasnt allowing me to get spark from the coils. I went through everything before landing to ECU being the fault. I purchased new crank and cam sensors changed the plugs, coils and even checked all the wiring but the ECu was the culprit. Went online to source the ECu and i can seem to find it available in Russia for a very high price which i wasnt willing to pay, so i went on a hunt to get it fixed. Did some research and found some info to probable fixes but none worked in repairing the ECU. I then did some digging and found that the American lancer ES, LS and OZ Rally uses the same engine. I made a post earlier in this forum if it can work to see if anyone had thought of the same and could have guided me in the right direction but no replies or hints, so i decided to face it head first blindly without any knowledge as to my first step. After some rsearch i found that the 2002 and 2003 Model lancer ECU for the same engine isnt equppied with an immobiliser and thats where i started. 


Guidlines on what i did:

I checked through ebay and found quite a handful of ECUs for the 02-03 Lancer Automatic at varying prices but ranging from $30 to $200 US. 

I ended up prchasing this one:


after checking it out i realised that my wireloom ecu plugs are different for this partcular ECu and i would need the wireloom ECU plugs for this ECu if i was ever gonna get it work. 

So i headed back to ebay and i found this:

Once i recieved these items now i set out to get the vehicle working.

Note: the reason my original Pajero ECU died is because the previous owner purchased a cheap coil that was faulty which in turn damaged the ignition drive on the ECu so i had to purchased new coils which are fairly cheap on Amazon or Autozone.

This is the parts after i recieved them.

I then went online to find any pin out diagram that can help me, which was easier said than done, but for ease of anybody else wanting to do this here are the diagrams i used and it worked out fine for me.

This is the Pajero iO pinout diagram (Note: pins 7 and 59 i did not connect as i dont know where to connect them or what they are meant for but my vehicle works fine without them, if anybody knows let me know)

The following diagrams are for the Lancer ECU and also the EVO 7 ECU its similar in alot of ways and helped me alot.

Those are the diagrams i used and it worked out easy for me.

Basically the plug section that have all the pin number for M/T and A/T just match them, M/T is the exact same as the Pajero ECU stock plugs, so on the pinout diagram match just what you see for M/T to A/T, which brings me to my next point, after doing this i realised that the manual 4G94 ECu cudve worked without me chaned the harness plugs, just two wires i wudve had to switch which is the fuel pump relay wire and the ac fan wire (pay attention to those two as it still needs to be switched in the A/T ecu wiring as well for the Pajero).

I was unfortunate to discover that the manual Lancer ECU uses the same plugs as the Pajero after i had already ordered the automatic ECU because the Pajero uses a TCM to control the transmission unlike the Lancer the uses a built in TCM in the ECU to control the transmission. So if anybody ever wants to do this i would recommend using the mnual ECU as it is way less work.


This is my finished wireloom

And now everything works great!!! 


Good Luck to anybody doing this, cheers.



PIN 7 and PIN 59 on The Pajero iO pinout connects to PIN 77 and PIN 89 on the Lancer 4G94 ECU, this definitely needs to be connected with an automatic Pajero 4G94 in order for the transmission to shift gears, the mystery has been solved (at least for me lol)

Guyana, South America - West Indies fever

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awesome work

awesome work on this.

knowing that the TCU is separate from the ECU, and only uses 2 wires to interconnect will make manual to auto conversion alot easier

Eustace Martin
Eustace Martin's picture
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Hey bro if you could email me

Hey bro if you could email me at mcdonaldmartin22@gmail.com I would be estatic. Í have hopes to do the same with my ecu. I have 3 pajeros one of them is exactly like yours.


I have a pajero io gdi 1998 4g93 engine h76w.

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Very good work. I also have a

Very good work. I also have a Pajero with a 4G94 engine which has 2 minor problems that seem to be related to a mulfunctioning ECU MR507582.

1: It does not activate the fuel pump relay. I think it should be activated when starting the engine but since the 12V comes from another relay that is being activated when the switch is turned on, I just use a jumper wire instead so the fuel pump will be turned on at the same time the switch is turned on.

2: It does not activate the EGR stepper motor or solenoid if you like, the ECU generates a P0403 error code and the engine light turns on. I replaced the EGR solenoid  but still the same.

I tried to find another ECU with the same part number but couldnt, I only found one with part number MD362114 from an older engine model 4G93 and I wonder if I can use it.


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I could be mistaken

Megazip.net is showing the MR507582 as available...


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