Mitsubishi montero ecm location - 1998 Mitsubishi Montero Sport

Question edited for clarity and add maker.
Question moved to model category.

Yes it is the same vehicle but it will need programming to the vehicle it is going into, VIN Number, Mileage etc.

https://www.google.com/search?q=1998+Pajero+vs+1998+Montero

https://www.google.com/search?q=auto+electrician+near+me

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Question edited for clarity.

Try an auto electrician. They have better scan tool computers and there may be an underlying issue with ECM, BCM or the Security Module.

https://www.google.com/search?q=auto+electrician+near+me

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google where is the starter relay located on a 2001 mitsubishi montero sport ls 3.4 litre
There is an abundance of free info


https://www.justanswer.com/mitsubishi/4q9go-mitsubishi-montero-sport-2001-mitsubishi-montero.html

Question edited for clarity

Not easy to get to or change according to this.

https://www.justanswer.com/mitsubishi/5693h-crankshaft-position-sensor-located-2003-montero-is-diagram.html

More
https://www.google.com/search?q=2002+montero+sport+xls+2wd+3.5+v6+crankshaft+sensor+location

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Chestion edited to add full make and model.
Questions moved to the correct category.

Montero fuel filter
It's contained in the fuel tank with the fuel pump. You access it through panels in the floor of the vehicle.

Tools for replacing fuel filter on '01 Montero - Mitsubishi Forum

HOWEVER, this disagrees and shows it underneath! Click images tab.

https://www.google.com/search?q=2002+mitsubishi+montero+fuel+filter+location

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The ECM (aka PCM-Powertrain Control Module) is located under the passenger's side dsah, behind the lower kick panel.

code p0400 refers to exhaust gas recirculation (EGR) system--flow malfunction===causes--hoseleak/blockage, basic setting not carried out (if applicable)--wiring---EGR valve--EGR solenoid---ECM
As the EGR unit is susceptepable to corrosion. Check it out or replace it

I think they are located on the foot kick panel on the passenger side of vehicle.

check the jack pins condition, check for brakes, check the harnhes for broken wires, try an other ecm from a junked or salvage or borrowed and see if it makes any difference