A story about slaying electrical gremlins.


Incomplete Idiot
So, I've got a 2003 Montero Limited. She's great, but as with most she's got a few problems. This is a tale about one of them, and like all good mysteries it actually begins on a dark, stormy night...

A little background on this poor girl's previous life...basically it sucked. Corporate lease, 5 total previous owners, last owner's choice mechanics were total hacks. You know that insanity that drives people to get the feels for abused animals, well, I've got a pinch of that for vehicles, and I'm sure Sarah McLachlan was humming in my head when I saw this poor rig. I just had to rescue it from these abusive bastards, nurse it back to health, and set it free to the life of mountains and sandy shores it was build and bred for. Anyways, as it relates to this tale, here's how I found the battery and fuse boxes once I got her home:


Broken battery box, corrosion everywhere, velcro lashing holding two fuse boxes closed, and a cheapo battery. Basic fixes included epoxying the battery box back together, cleaning and painting rusty hold-down components, and cleaning up all the visible corrosion. All things electrical seemed good. 14.3v on start-up, stayed between 13.8 and 14.1 while driving, above battery voltage under heavy load (low 13v or so). Battery consistent 12.7v, load tested fine at work. Good...I can focus on other stuff, right? Well, then comes a problem...

I first noticed it one dark and stormy night after coming to a stop. The Montero's idle dropped really low, shuddered, and stalled. It started right back up, but I immediately noticed a problem with the vehicle's voltage. I have a plug-in digital volt meter that I keep plugged into the center console's 12v outlet, and what I noticed was that the voltage would drop down to 12.5v or less when I wasn't on the skinny pedal. I turned off the a/c, fan, and rear defroster and the voltage climbed back up to ~14.0v, both when driving or idling at a stop. I chocked it up to maybe having a bad ground or hidden corrosion that kept the vehicle's alternator from keeping up under a full load (hot, rainy night meant I had almost everything on: a/c, wiper, lights, rear defrost, etc.). Told myself I'd take care of it later, turned off the a/c, and made it home with no more troubles. Looked around a little and saw that simple things like having a bad serpentine belt can manifest during rainy conditions, slipping more than normal. It doesn't turn the pulley, thus voltage drops, thus stalling. Ok, that sounds logical. Maybe I just need a new belt.

Problem summarized: Montero's voltage drops below 12.5v at idle (in drive, not park) with a/c and other accessories on causing the vehicle to stall.

So what did I do? Change the belt? Uh, well...we loaded the kids, a fridge, and a few hundred pounds of camping gear into the rig and went on a 500-mile dirt road trip. I told myself, "It'll be fine. Just don't use the A/C."

Monty Tree.jpg


Incomplete Idiot
That family road trip is a tale for another thread, but as it pertains to this story suffice it to say we made it home safe, sound, and very satisfied. Four straight days of dense fog and rain meant that we were forced to put more volts on tap than I planned, but with a steady eye on the voltage meter we kept the Montero moving. Problem not solved, but not worse.

Well, at least until about a week ago. One morning as I was backing out of the driveway I felt a shudder, and then later at a stop sign, a stall. No rain, no a/c, just headlights and the voltage can't keep up when idling at a stop (in drive). Limped her into work with some creative coasting, avoiding full stops at almost all cost with my mind wondering "what now?" First thought went to corrosion, grounds, connections, anything I could check while at work during breaks. Here's what I found:


I cut back the heat shrink on the positive cable to find some pretty thick corrosion penetrating into the wire strand and crimp connection. Also, the fusible link that comes off the positive post was in terrible shape. Not only was it corroded, but the yellow ABS fusible link was missing it's plastic cap (how does that even happen?!). The negative cable's terminal looks like it's been replaced...and I'm not sure if what they replaced it with was meant to go on a vehicle's battery. You can see the teeth marks from the metal snips they used to "shape" the terminal to fit. Whether it's related to the stalling issue or not I realized I need to get new terminals for both wires. But being at work with no access to proper terminals or heavy gauge crimping tools I just did what I could to try to get home.


I cleaned everything back down to the brass and copper nature intended, and tried using some spray on battery terminal cleaner to get what I could out of the positive cable. I completely disassembled the fusible link box, cleaning every metal contact point inside and out before applying that red terminal protector paint stuff in the slim hopes that it would prevent me from having to take that box apart again (13-year old plastic does not like to be touched, and will let you know by cracking in that face of your careful attempts to pry). A few more things I saw...


Well, epoxy might fix your battery box, but 10 miles on Bald Mountain Jeep Trail will probably break it again. I'm sure my battery has not appreciated bouncing around under the hood for who knows how many days now. I rechecked the battery with a load tester and all seems ok...but, I don't know. Anybody who's read Montypower's build thread knows that a battery can throw you for a loop. I'll be keeping my eye on that Duralast guy, for I suspect his name ain't all in keeping with his durability. I also cleaned the negative ground point under the fuse box. Still had the factory paint under that flat brass connector (?), but I took it down to the metal and reattached everything.

Problem solved? Well, let's just say it got better and got me home, but it's not fixed. It's not stalling at a stop with a few accessories on (ie. lights), but with a/c and full fan, you bet'cha. All that stuff definitely needed doing (and a few things more), but the problem still comes back under heavy electrical load. Voltage drops down to 12.5v and then follows the rpms.

When I first started looking for a Gen3 Montero late last year I came across a green and tan one. It was the first green one I had seen in my internet searching, and as I was scrolling through the pictures I came across a front view picture of the vehicle. I have four sons, the oldest of whom is five, so we watch a good bit of kids movies around the house. Well, one movie came immediately into my mind as I saw this green Monty from the front. You know how once you notice how something looks like something else you kinda can't help seeing that something else everytime you look at that something? Well when I look at my Montero I think, "Montero's are kinda like onions...layers, Donkey. They have layers." And mine has layers of problems that I'm slowly pulling back.



Incomplete Idiot
At my work I'm young enough to be everybody's kid. I'm the only one under forty so I'm the shop's token whipper-snapper or whatever they call it. They quip at me with puberty jokes and I hit back with social security filing forms in their lockers. We have a good time. But being young(er) means that I'm assumed to be the designated IT professional, born with an innate knowledge of all things computer. Alas though, I ain't their huckleberry. I was born somewhere just before they started handing out computer degrees with birth certificates. I can still remember a time before the internet was a common thing (and cell phones too for that matter), and as the internet became everything to everybody I just wasn't into it. Needless to say when it comes to computer stuff I've got an old timer's brain in a Millennial's body (God, I hate that label). "Just Google/Youtube it" is a bitter medicine that I'm slowly coming around to understand and appreciate. When those words enter my brain the response is probably something similar to what a Millennial hears when told "That's what libraries are for!" Whichever side of the technological divide you're standing on, the common hiccup is "I know there's probably an answer in there somewhere, I just don't know how to find it."

And so, back to the story: in my efforts to identify the electrical gremlins preying upon my poor, misunderstood Japanese ogre I find myself looking to an unfamiliar ally...Al Gore's famous "the Internet." Don't get me wrong. I use the web like everybody else for everything from bills to emails to Facetube and Netflix, etc. My hesitations with the internet isn't from that kind of stuff, it's from something I'll explain like this: If you don't know nothin' about something, like say life stages of a tutsi fly, and you go into a library to find some info, at least you've got the peace of mind that if they've got a book about tutsi flies it is probably pretty accurate in the info it's putting out. They don't just let anybody print out their fancies about stuff, bind it up, and stick it on the shelves. Publishers, citations, the Dewey Decimal System, etc. are all at work to ensure that only the smartypants people's published works get on the shelf and into the hands of me, the tutsi fly know-nuthin. But with the internet, well, I think we can all agree that it's a little harder to know the electrical engineers from the 12-year olds pretending to be so. The digital "shelves" are full of who knows what...especially when you're a "total noob."

And if you haven't guessed by now, I am a complete Mitsubishi noob, and to only a little bit lesser degree a mechanical novice. If working on cars was karate I'd be like that guy that won some free lessons at a car show, showed up for two classes, loved it, but when he found out it actually cost a bunch of money decided to go home and watch Bruce Lee movies to further his MMA ambitions. A little background on me, well, I'm married with four young boys...so basically I'm dirt poor most of the time, but happy almost all of the time. I've owned a Jeep Cherokee since I went to college a decade ago, and fell in love with it despite it constantly acting up here and running funny there. Having no money meant trying to figure it out and fix it myself. No mechanical background meant turning to forums full of genuine Jeep sages mixed together with high school heretics, as well as finding out how helpful/harmful Youtube could be. After 10+ years of that, mixed with me ending up in the maintenance guy career path and I'd say I can Bruce Lee with the best of them ("them" being the other Rex Kwon Do wannabes).


Well, now enter the Montero. Four kids are too much (legally) for an XJ to haul around camping and galvanting, and being a poor man I can't afford the Toyota tax, so forget the Land Cruiser. Where to go, and lo and behold into view comes this thing. She's big, and a little ugly from some angles, but them there are birthing hips fit for carrying my youngins. It's got that function before form kinda attraction going on, and after growing on me for a few months we pulled the trigger on our '03 Limited. I knew it needed some work, but realizing I couldn't afford a pristine example, and figuring from my experience with my Cherokee that everything I needed to know was hidden somewhere in the bowels of the internet, I felt good about it. She needed a good home and we needed a good conductor for our many adventures. Little did I know how much deeper and harder to find would good info on these, shall we say, "not quite as common as a Jeep XJ" Mitsubishis be.

If there really is a generational divide, where on one side you've got old timers that understand everything mechanical and the other side whipper-snappers that have the computer stuff all sorted, then I feel like I was born somewhere between the two. Problem is, it was more in a valley between the two, not really up to speed on either. But if I look at this on the bright side, maybe this gremlin-laden Montero is the means to a metaphorical mountain top that will help me get a good look around. That's what this overlanding stuff is all about, right? Not so much the destination, but the journey. I think our Montero is therefore the perfect overlanding vehicle for us, current electrical gremlins and all.



Overlanding Nurse
Bee-yoo-tiful! :luxhello:

I'm a learn-as-you-go guy myself, and have certainly learned a lot from my Gen III. It hasn't been about problems so much as about solutions...understanding the nature of the beast: a 15 year old rig that gets pounded pretty hard on occasion. I'm consistently amazed at how well she takes it, how competent she is, how comfy and capable to the double-duty role of overland rambler and family wagon. Plus, now that both daughters are driving, it tickles me that the Mighty Mitsu is their first and favorite choice of the four vehicles in our family, even over mom's Volvo!

You've got the skills and, perhaps more importantly, the insight and sense of humor. I look forward to following you and the family along on your adventures!


New member
No more electrical. Anything but electrical please, I just can't take it. And I think you have a failing alternator voltage regulator...


Expedition Leader
Subscribed. I have a Gen 2.5, but enough electrical issues to share if you need more :)


Incomplete Idiot
Well, been trying to find the time to post an update. Here goes...

The internet hasn't been much help with things, but it did provide me with a copy of the Factory Service Manual. It, in a round-about way has shed a lot of light on how this machine is supposed to work. I dove into it with my lists of issues in the hopes that I could WebMD style cure things. My two main symptoms included: low idle speed (450 rpm when warmed up idling in drive) and low voltage (< 12.6v) idling at a stop (in drive with the a/c & fan on max) leading to stalls. I couldn't find a section entitled "How To Fix John's Stalling Montero" so I just had to start poking around and hope to stumble onto something promising. Pretty much anything idle or electrical-related was considered as a possible fix. Here's a basic nutshell of all that has occured:

  • Cleaned Throttle Body (13Aa-11)
  • Checked Throttle Actuator Control Motor operation (13Aa-24) - ok.
  • Checked Throttle Position Sensor (13Aa-18) - ok.
  • Checked MFI Relay, Throttle Actuator Control Motor Relay, and Fuel Pump Relay (13Aa-16) - ok.
  • Replaced drive belt, checked Tensioner indicator marks (ok), cleaned odd tacky rubber (?) off idler pulleys (11A-5)
  • Checked Evaporative Emission Purge Solenoid (17-62) - ok.
  • Checked and cleaned EGR Valve (17-63) - ok.
  • Refreshed all engine bay Ground Points (70-4 thru 70-7).
  • Replaced positive & negative battery cable terminals and repaired broken battery box (again).
  • Checked "Idle-up" operation (55A-125) - ok.
  • Attempted to check for A/C Switch 2 Signal (13Ad-70), which is the signal that your A/C computer sends to your PCM telling it that the A/C is on and therefore idle needs to increase...test failed due to misprint in FSM, giving me 4 MIL codes.

Here's where a little bit of dumb luck came my way. The four MIL codes were P0183, P0113, P0108, and P2138. Putting those into Google with Montero attached took me to the first useful thread I've come across: http://www.justanswer.com/mitsubish...o-limited-2004-montero-limited-dies-when.html. There I met an '04 Montero owner with the same problem as me and Doug, ASE Certified Technician. He'd directed the owner down most of the diagnostic procedures I'd performed, and when they got to looking for "A/C Switch 2 Signal" the owner reported the same MIL codes...due to the FSM having a typo (you can't start the vehicle with the D-134 connector unplugged). This owner's issue turned out to be engine load related, and a transmission fluid flush solved his issue. Apparently the combined load of the A/C compressor and transmission when in gear (due to improper fluid) caused the Montero to bog down and stall. Not an idle or electrical issue directly...but a transmission (torque converter) issue. Never would have thought of that...I just don't understand how "Max A/C" and normal A/C can cause the idle to be behaving so differently since the compressor load would be "on" in either case. I don't think these compressors stage or anything...they're either on or off. Makes me lean more towards a communication issue for me...I really hope I don't have a bad PCM!

So here's where my Montero stands as of today: After all the basic maintenance and refresh stuff I did the electrical voltage is much more consistent, but the idle is still lower than the FSM says is normal (700 rpm +/- 100), and I still get the stalling when idling in drive with the a/c on max. I can run the A/C on a lower setting with no issues, but not on max. And I still haven't ruled out the Alternator being an additional problem. Here's the list of things remaining to do:

  • Check for A/C Switch 2 Signal by "backprobing" PCM connector D-134 (13Ad-70)...I really hope I don't have a bad PCM.
  • Check Alternator with Generator Voltage Drop Test (16-5), Output Current Test (16-6), and Regulated Voltage Test (16-8).
  • Have transmission fluid professionally flushed and refilled with Diamond SP-III

Wish me luck...I feel like I'm getting closer, but repairs will have to wait another week or two. We've got another trip to take, this time down to the beaches of North Carolina's Outer Banks, haha. We'll just have to survive without "Max A/C"...:)


Expedition Leader
The generator tests are pretty easy to do. In my case, they never revealed any issues other than high voltage (15+ volts). Regarding the Idle, have you just adjusted the idle at warm mode?


Incomplete Idiot
Adjust the idle...How do you do that? I never saw anything like that in the FSM. Everything I could gather pointed to the PCM controlling everything with the idle...and short of having a MUT-III scanner there isn't much I can do there.


Expedition Leader
Adjust the idle...How do you do that? I never saw anything like that in the FSM. Everything I could gather pointed to the PCM controlling everything with the idle...and short of having a MUT-III scanner there isn't much I can do there.
13A-49. There's a little grayish flat cap near the throttle body on top of the intake. Pop the cap off, put a long skinny regular tip screwdriver in there, and a quarter turn one way or the other will bring that idle speed right up. There is a whole procedure for doing it the right way on that page reference, but step #6 is the important one.

Edit: For me, I removed and cleaned the idle air speed controller thing, and then cleaned the throttle body really thoroughly with throttle body cleaner spray and rags. Made a huge difference.


Incomplete Idiot
I'll check for that later. Thanks for the tip. I'm pretty sure though that after 2003 when they went to the 3.8 everything idle related became logic based and computer controlled. I don't have any of your typical mechanical idle devices (IAC motor, TPS, etc.). The throttle body itself is completely drive by wire...no mechanical linkage. The computer tells everything what to do based on a myriad of sensor inputs.

I'll check the FSM and my engine bay later today to make sure though. It'd be wonderful if it were that easy. :)


Incomplete Idiot
13A-49. There's a little grayish flat cap near the throttle body on top of the intake. Pop the cap off, put a long skinny regular tip screwdriver in there, and a quarter turn one way or the other will bring that idle speed right up. There is a whole procedure for doing it the right way on that page reference, but step #6 is the important one.
I checked into it and as I feared we're reading from two different FSMs about two different animals, my 3.8L w/all its electronic sorcery and your 3.5L w/all its mechanical dodads. My PCM runs the show paying close attention to the ECT (engine coolant temperature) sensor, various air flow readings, barometric pressure, the phase of the moon, and real-time Mitsubishi stock index performance to determine what to tell the Throttle Actuator what to do. (Maybe my low idle is related to Mitsubishi's current corporate woes...or maybe it's depressed that the new Pajero will probably not be coming to the States, who knows).