QuestionQUESTION: Roland measured MAP harness at the violet wire and the others 0 voltage.Verified the low resistance,both plugs in #5 read 01.0 ASD fuse in 0.09,ASD relay jumper from terminal front to back 01.0,#1 fuse removed #5 registered 00.9 same numbers with Generrater and EGR 00.9
ANSWER: Hi Steve,
Are you saying that one or more of these measurements were taken with fuse #5 inserted in its socket but that the fuse did not blow immediately, in contrast to what you said that it had in the past?
If so, and the battery has not some how discharged, then I am puzzled because if indeed the resistance to ground of pin #53 of the fuse socket is showing 0.1 ohm then if the battery has any voltage on it the fuse should blow immediately. Check that there is 12v showing on the other pin of the fuse socket, and if you want to put at risk a fresh fuse put it in. But I would expect the fuse to blow instantly. Maybe we are misunderstanding each other.
If you haven't put a fuse in the socket, fine you don't have to experiment. But from what you tell me it appears that PCM will short out the fuse if you have both its plugs inserted when you do so. If you want to test my theory feel free to do so, after one last measurement of the resistance to ground of the #53 pin of its socket. If it doesn't blow, then turn the key to "run" and see if that blows the fuse. The conditions for this specific test would be to not have the ASD relay in its socket, nor would you want the jumper between the front and rear pin of the socket. Leave all the other plugs in whatever condition they are right now (except remove fuse 1 and remove the PCM plugs) because I am not clear yet as exactly what is going on.
If by chance the fuse doesn't blow, the turn off the key, insert fuse 1 and see if it blows. If it doesn't insert the rear PCM plug and see if it blows. If not, insert the front PCM plug and see it it blows. If not insert the ASD relay and turn the key to run and see if it blows. Let me know when it blows, if it does.
Roland
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QUESTION: Hi Roland I took the readings with the fuse out because yes it would blow as soon as I put it in.Everything measured 00.9 the last thing I measured was when I plugged the EGR in, # 5 read 00.9,(I plugged everything in then measured in the order you gave me,not the order I sent you then I went to the instruction of checking MAP sensor for the 5v and got nothing and also noticed one of the three was the orange and green I noticed when measuring the lavender and white wire so I wrote the follow up to give you a heads up . Thanks for all your time and your many efforts
ANSWER: Hi Steve,
Just one more time...if you unplug the two pcm plugs, and then measure the resistance to ground of the #53 fuse pin, will it then be over 200 ohms (e.g. no reading)?
If that is so, and because you have examined all those plugs that are powered when the PCM is plugged in, and you can only get an "over 200" reading with the PCM plugs removed, I lean toward the belief that the PCM is shorted out.
If you want to try one more time, and have a spare 20 amp fuse, then first remove fuse 1 and of convenient all the other sensor/injector/etc. plugs you have earlier removed, and also remove the two PCM plugs, then remove the internal jumper in the ASD socket and put the ASD back in. Then put in the 20 amp fuse. If we are on the right track the fuse won't blow. Then put in the front PCM plug and see if the fuse blows. Then put in the rear PCM plug and see if it blows. Then turn the key to "run" and see if the fuse blows. Of course stop as soon as the fuse blows and let me know when it blew.
Roland
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QUESTION: Hi Roland ,Well after unplugging everything that you mentioned,I put a 20amp fuse in fuse #5,took the jumpers off the ASD relay replaced with good relay also removed #1 fuse and it blew the fuse when I plugged the no.1 plug( Closest to the radiator)into the PCM.It was the first thing I plugged in
AnswerHi Steve.
That is PCM Plug No. 1 and it draws immediately on the fuse 5 at pin 46 so that would suggest that it is drawing more than 20 amps. It no doubt creates the 5 and 8 volt power supplies which I understand that you did have disconnected so those would not likely be the cause of the "overdraw" of current. So at this point I would recommend that you look for a replacement PCM at a wrecking yard or from an auto parts store or from the internet. You could measure the resistance between pins 46 and 50 of the PCM plug socket* just to verify it is a dead short (or at least leas than 0.6 ohms) to corroborate this analysis. You should be able to find a used one if a new replacement is expensive. If you got it out of a wrecking yard you could verify before you buy it that the resistance between its pin 46 and 50 is a lot higher than your present PCM shows.
Do let me know what you find.
Roland
*Pin 50 is one of the corner pins of the socket (look on the plug itself to view the pin numbers) and then count backwards across that same row to find pin spocket 46. This measurement will be worth doing so as to "prove" that the PCM is shorted even with nothing else drawing upon it.
