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Car Forum / Mitsubishi Cars / June 2004Diagnostic Scanner???
Is there an "non-dealership" diagnostic scanner that I can purchase to read diagnostic codes for my 1.8L Mitsubishi engine in my 1991 Plymouth Laser? Craig Yes, but do you really need one. My son has the exact same car, and we've been down this road. Caution, follow these instructions at your own risk, they may damage your car if you do it incorrectly. You can get the codes out of the ECU by attaching a voltmeter to pin 1 of the OBD output connector, and grounding pin 12 (ignition key in "RUN" postion). The ECU then outputs a series of pulses, that indicate the error code. The connector is located by the left kick panel, by the fuse block (may have a black protective cover on it). As the connector pins face you, with the keyway on the top row of pins, pin one is on the top row, extreme right. Pin 12 is on the lower row, extreme left. Be aware that if the output is a constant high signal, the manual says to replace the ECU. But at this point you'd already guessed this, because the care won't run. And that's a whole nother issue. Under this condition, some (most) ECU's can be repaired (done it three times already on three different ECU's). You should be aware that ECU's of this vintage (in Mitsu world) are world renowned for there failures. If yours is still working, I would suggest that you get it upgraded ASAP. If you know your way around a soldering iron, the repair will be less than $5.00,US, including parts Any shop manual for this car will have the instructions and the codes listed in it. If you don't have one (or can't borrow one) check with your local library. Even with a scan tool, you'll need the manual to decode the scanner output. OBD for this vintage is not industry standard, and every manufacturer had a different set of codes, and ways of getting at them. By the way, what is your problem? Oh and another thing, there are after market data loggers available for this ECU, if your interested. > Is there an "non-dealership" diagnostic scanner that I can purchase to > read diagnostic codes for my 1.8L Mitsubishi engine in my 1991 > Plymouth Laser? > > Craig >By the way, what is your problem? The problem is thatthe car has started without a problem since new and the other day it would not start. I did some diagnostics on the fuel delivery system, and I was able to manually power up the fuel pump, but it would not pump via turning on the ignition key. So... I checked the resistance on the EFI control relay (or whatever it is called) and some of the readings were off a bit. I purchased a new relay and it did not correct the problem. The car still cranks but does not start. As soon as it stops raining here, I plan to check out the coil and spark generation and do more testing on the fuel pump. It just seemed strange that the car would run fine one day and not start (but will crank) the next. It seems as though it might be electrical. I do have the service manual and I did find the codes (by pulse) so I plan to go out and purchase an analog voltmeter to decipher these pulses. If the ECU turns out to be bad, where may I ask, did you find info on how to repair one? Thanks for the info. Any suggestions would be appreciated. >Oh and another thing, there are after market data loggers available for this >ECU, if your interested. [quoted text clipped - 4 lines] >> >> Craig UPDATE Tonight I checked for spark at the plugs and there was none. I checked out the coil and the primary, secondary, and insulation resistance was fine. While I was in there, I went ahead and replaced the cap and rotor because they were worn. I then tried to start the car - it cranked but did not start or even sputter. Then I went to the ECM to see if I could get any diagnostic codes from it. I connected an analog voltmeter to pins 1 and 12 and turned the ignition to on and I got no reading at all. I thought that maybe the voltmeter might not be working so I tested it on a battery and it read 12.7 volts. I tried again, still nothing. I tried a digital voltmeter on the lowest scale. I got a less than 1v reading with no pulsing of any kind. According to the book, when the ECM is bad it is supposed to remain at 12v. When the ECM is functioning properly, it should pulse evenly on and off. I then checked all fuse links and fuses under the hood and they all looked fine. ANY suggestions????? >>By the way, what is your problem? > [quoted text clipped - 24 lines] >>> >>> Craig Boy, your description of the problem sure points to the ECu. That is the exact way my sons car went, twice. I say twice, cuase we went to the auto wrecker, got a salvaged module, didn't get it upgraded, and it failed the same way three months later. After I bought the third module, I compared it to the failed modules, found the problem, then repaired all three before installing one in my sons car. The problem is the electrolytic capacitors. There are three or four of them. They tend to fail and leak electrolyte onto the PCB. The fix (if your module is still working), is to just replace them. If your module has failed, usually just replacing the caps, and repairing any corroded traces, is all that is needed. After the repair, wash the board, and reseal it with a conformal coating (clear lacquer spray paint works OK) I'll be damned if I can find that web site that gives the instructions on how to do it. It was a good site, they even had pictures. Someone on this news group could probably help here. One of the modules my son had (the last one) had a black hole blown into the PCB by the exploding cap. I cleaned out the carbon, replaced the traces with wires then sealed the PCB with conformal coating, that was last year, still no problems. > >By the way, what is your problem? > [quoted text clipped - 24 lines] > >> > >> Craig Thanks, I will take it (the ECM) out in the morning and examine it. If anyone knows of the web site please post the URL here. If I find it via a search engine I will also post it. >Boy, your description of the problem sure points to the ECu. That is the >exact way my sons car went, twice. [quoted text clipped - 46 lines] >> >> >> >> Craig I just did a parts search online and .......... OUCH $1055 !!!! for a new ECU Now I know why Nirodac repairs his!! >Thanks, >I will take it (the ECM) out in the morning and examine it. If anyone >knows of the web site please post the URL here. If I find it via a >search engine I will also post it. I found the website -- Thanks so much for letting me know about this. Wish me luck!! http://www.tmo.com/howto/ecu1g/caps.htm >I just did a parts search online and .......... >OUCH [quoted text clipped - 7 lines] >>knows of the web site please post the URL here. If I find it via a >>search engine I will also post it. Yep, that's the site. Read the entire post before doing anything. Even if the caps aren't leaking and everything looks good, check the big fat trace under the 100 uf capacitor. On two of my ECU's there appeared to be a cut in the trace, which was then covered over with a spot of paint, I suspect from the factory. I rejoined the trace and it work again. That is a 5 volt power rail that goes to just about every chip on the ECU board. Using your new meter, you can measure different points along the bus to ensure that power is reaching the chips. And do check the ECU code output FIRST. If nothing is coming out of the test point, then it's your ECU. If the test point has a steady constant pulse stream, then the ECU is probably OK. Remember the ignition must be in the run position to power the ECU for code outputs. Good Luck and let us know how you made out. > I found the website -- Thanks so much for letting me know about this. > Wish me luck!! [quoted text clipped - 12 lines] > >>knows of the web site please post the URL here. If I find it via a > >>search engine I will also post it. OOOps, should have read all the previous posts before mouthing off. I see that you have checked the ECU for output. Yep, that's the site. Read the entire post before doing anything. Even if the caps aren't leaking and everything looks good, check the big fat trace under the 100 uf capacitor. On two of my ECU's there appeared to be a cut in the trace, which was then covered over with a spot of paint, I suspect from the factory. I rejoined the trace and it work again. That is a 5 volt power rail that goes to just about every chip on the ECU board. Using your new meter, you can measure different points along the bus to ensure that power is reaching the chips. And do check the ECU code output FIRST. If nothing is coming out of the test point, then it's your ECU. If the test point has a steady constant pulse stream, then the ECU is probably OK. Remember the ignition must be in the run position to power the ECU for code outputs. Good Luck and let us know how you made out. "I'm a Movie" <c..osb.o..rn@.ep.ix.n.et> wrote in message news:0j45c0d7r1rlcc22t1ti6c00ej1jj16dvu@4ax.com... > > I found the website -- Thanks so much for letting me know about this. > Wish me luck!! > > http://www.tmo.com/howto/ecu1g/caps.htm > > > On Sun, 06 Jun 2004 03:19:45 GMT, I'm a Movie > <c..osb.o..rn@.ep.ix.n.et> wrote: > > > > > > > > >On Sun, 06 Jun 2004 03:13:47 GMT, I'm a Movie > ><c..osb.o..rn@.ep.ix.n.et> wrote: > > > > > >I just did a parts search online and .......... > >OUCH > > > >$1055 !!!! for a new ECU > > > >Now I know why Nirodac repairs his!! > > > >>Thanks, > >>I will take it (the ECM) out in the morning and examine it. If anyone > >>knows of the web site please post the URL here. If I find it via a > >>search engine I will also post it. > >> > > > >>>> > >>> > |
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