Can't get Trooper Battery to take a charge! ECM?

wahtahwahtah Member Posts: 2
edited May 2014 in Honda
I'm having a problem getting the battery to charge. I have replaced it, as well as the alt, twice. cleaned alt ground, replaced batt connections and even followed the wires back to ecm. It shows that their is power going in to the ecm. Where do I look from here?


  • wahtahwahtah Member Posts: 2
    I need to know if thiers anything else I should check before I have to wright a big check for ecm. I Replaced alt, bat connections, battery,and cleanned alt ground. ANY SUGGESTIONS WILL HELP
  • boxtrooperboxtrooper Member Posts: 843
    Can someone here provide an elctrical diagram of the charging system on watah's (what year is it?) Trooper?
    The charing system usually consists of the alternator and a regulator. Sometimes the regulator is inside the alternator, sometimes it is external. Do you know where your regulator is?
    Some charging systems need a signal to go ahead and start charging, this signal can come from a switch or a relay. I think the purpose is to not energize the field winding of the alternator unless it is turing and so can generate more power to prevent the field winding from draining the battery. You need an electrical diagram showing the connections on the alternator, if it has an enable input, follow the wiring diagram to see what eneble comes from.
    Sorry, I don't have a Trooper manual to look this stuff up. I read about the enable signal when looking at aftermarket alternators for potentially replacing an alternator on another vehicle with a higher capacity version. Here is some online stuff I just searched for:
    These people might be able to talk alternator tech very well to help:
    While you're talking with them ask what model fits the Isuzu Trooper and how high an output can be fitted into a Trooper as a bolt in replacement.
  • transducertransducer Member Posts: 7
    does anyone know where the voltage regulator is located on a 96 dodge neon???
  • steverstever Guest Posts: 52,454
    Unlikely, since this is an Isuzu discussion!

    Try the Dodge/Plymouth Neon discussion. Good luck!

    Steve, Host
  • longbrdlongbrd Member Posts: 3
    My 1988 Trooper began acting erratically so I tuned it up, set timing and it ran great. The next morning it was back to running poorly, loss of power and backfiring. I had it towed to a local Japanese car specialist who informed me the ECU was dead. He said there wasn't much I could do and I have had it sitting for a month while I figured out what to do with it? Saw today on the net where a company will rebuild your ECU with a lifetime guarantee or sell you a new one for $500. Has anyone ever changed their ECU? Is it a simple plug in or is it more involved? The rebuild is $299, so I would like to feel comfortable about doing this. Any suggestions or recommendations? My family and I love this truck and I would hate to have to junk it.
  • atfdmikeatfdmike Member Posts: 414
    Hi Boxtrooper, I have been waiting to see if Watah gave any specifics on his vehicle. His carspace profile only shows a Honda, so I won't be of much help to him by way of looking up info. I think you nailed the answer with your reply, he just needs to know the schematic for his particular vehicle.
  • atfdmikeatfdmike Member Posts: 414
    Hi, did your "car specialist" get any codes out of the ECM (ECU) when he checked it? Replacing an ECM is relatively easy but expensive for the part itself. Most reputable rebuilders warranty their unit for a brief period. The ECM relies on several inputs in order to work correctly. Any one of the sensors could also be at fault. You can check your ecm yourself: To access trouble codes, a test lead (white wire) and ground lead (black wire) are branched from the wiring harness under the center console near the ECM. With the ignition "ON" connect these two leads together. The "Check Engine" light will begin to flash code 12. Code 12 consists of one flash, a short pause, then two flashes. After a longer pause, code 12 will repeat two more times. This check indicates that the on-board diagnostic system is functioning. If no other codes are present, the cycle will repeat until the ignition is switched "OFF."
    I have posted a picture at :!v=

    good luck.
  • atfdmikeatfdmike Member Posts: 414
    Hi again, I probably should have added to my previous post that if your check engine light does not perform as I described, flashing a 12 code, then you can assume that it (the ECM) is defective. Just make sure that the fuses are good and the dash check engine light does light up when tested. If you go with a new or rebuild ECM, remember that it is an electronic device and must not be exposed to static electricity or mis treated while installing. It does have at least one connector that disconnects it from the wiring harness, and these are generally easy to figure out how to remove. Let us know how you make out. Best!
  • longbrdlongbrd Member Posts: 3
    Thank's for the added info.I plan on checking it out this weekend and will let you know what I come up with.
  • longbrdlongbrd Member Posts: 3
    Checked the ECM and it flashed as if OK, with no problem codes and no check engine light on. Trooper idles great but when hitting the gas sputters and has a general lack of power. Seems like the timing isn't advancing. I do have a hole in the flex exhaust pipe but would not think this would effect the engine in such a manner - just create a loud exhaust noise. Now I 'd hate to go the new ECM route is it is not the case. Any suggestions other then drive it over a cliff are welcome. Thanks for your guidance with the ECM.
  • tcollinstcollins Member Posts: 5
    Quick question. I have had battery charging problems With my 94 passport. About 2 years ago the alternater was replaced and was fine (a poorly installed alarm system was removed as well). About a week ago I had to get it replaced again. My brake and battery light were on together and the battery would not stay charged. It finally went dead on the highway. The odd thing was that (before it died) it did weird things. At low idle it was fine, but around 2.5+ rpm the battery system lit up. The alternater was replaced less than a week ago and just started to flare up AGAIN!!! Am I missing something?!?! Also to note, the battery is only 4 months old as well. ECM, wiring, battery cables? Please help :sick:
  • paisanpaisan Member Posts: 21,181
    Did they charge the battery before cranking it up? I killed 2 alternators and a battery when I swapped the alternator and didn't charge the (now dead battery) and figured the alternator would re-charge it.

  • atfdmikeatfdmike Member Posts: 414
    The symptoms of multiple dash lights coming on is typical for Isuzu's with alternator problems. I have had the experience of buying a rebuilt alternator and having it go bad the next day, so don't discount that you may have another bad alternator. It should have some kind of warranty. Good luck
  • tcollinstcollins Member Posts: 5
    As far as i know they did charge it. The alternator is a brand new one, and the one before this one was fine for almost 2 years. The car ran fine for a couple of days so it makes me suspicious of everything. It just makes me think that it's something more.
  • atfdmikeatfdmike Member Posts: 414
    I think you have to have the new alternator checked to see if it is working properly or not. Best place to start, I believe. One owners opinion.
  • tcollinstcollins Member Posts: 5
    I had the alternator checked before I got the new one. Two places said that it was operating fine. I got it replaced anyway just to make sure. But now this one is doing the same thing. I had it checked at a local store and they gave me the same thing. "It runs fine".... but still the problem persists
  • tcollinstcollins Member Posts: 5
    anymore ideas anyone?
  • atfdmikeatfdmike Member Posts: 414
    Have you tried the Honda Passport forum?? Maybe someone there has experienced your problem and dealt with it.
  • tcollinstcollins Member Posts: 5
    i would if there was one.
    plus the izuzu rodeo and the honda passport are almost exactly the same car, same owners (and haynes) manual and same components
  • brightguybrightguy Member Posts: 5
    I cleaned the two plugs attached to the fire wall, going to cruse control, My 97 pontiac had no power to start the car even with 12v at both ends. After cleaning inside both large plugs started right up and my intermittant hu.d display seemed to clear up too. :)
  • rawood321rawood321 Member Posts: 2
    What you are describing is exactly how my 1991 Trooper is acting. I did an entire tune up on it, but I still had the "loss of power" issue. Did you ever resolve your issue by changing the ECM, or did it end up being something else?
  • mentalboymentalboy Member Posts: 2
    Hi. I purchased my trooper 3 years ago. It had about 150k... was lady driven, well maintained, never taken off road. I have been very careful with her. She's never abused and is regularly maintained. She just clicked over 200k.
    I noticed on my last trip down-island, that her power was down. It hasn't gotten any worse, and she still pulls 75mph (about 120Km/hr) on the flats without any problem, but as soon as there is any uphill grade, she sucks. Can't figure it out, and I've mentioned the problem to several mechanics, and they can't figure it out either.
    Do I smell an engine overhaul or rebuild?
    Please help!!
    Thank you so much.
    Paul, Alert Bay, BC, Canada
  • ozjackozjack Member Posts: 1
    Hi, I have the aussie version of the Trooper, Holden Jackaroo. I have a troublesome electrical fault. The car is a 1989 2.6 efi manual.
    The battery is not getting a charge. I had the auto sparky go over it and he reckons the problem is around the relay area from a possible ignition feed. The alt is working fine, the battery is fine as tried and tested at the workshop, the alt was even removed from the car and tested independently. When I run the meter over the battery only 11.35 volts and under load 11.29 volts. Clearly not enough. The car starts second turn of the engine when the battery is charged. I had some rewiring done to the fan and an ignition feed was created as the original was no good.
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