95.5-2004 Tacomas & 96-2002 4Runners 4th gen pickups and 3rd gen 4Runners

obd2 port not working with scanner + fuel pump keeps priming= bad ECU?

Old Oct 17, 2012 | 05:41 PM
  #1  
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obd2 port not working with scanner + fuel pump keeps priming= bad ECU?

yep
tested before the obd2 port with several scanner tools and all of them shows error in connecting,all wires in the obd port are good 4 and 5 are grounds 7 is signal from ecu and 16 is b+ constant,also the fuel pump keeps priming all wires and relays are ok cam sensor test good.all ecu wires and pins are ok and seems to be stock.

can it be that the ecu is bad?
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Old Oct 18, 2012 | 04:37 AM
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From: DFW TEXAS BABY!
Might be worth seeing if you can borrow another ECU to test out if possible.
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Old Oct 18, 2012 | 03:37 PM
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my uncle have a 2000 limited but the part number of the ecu is different, and if im not wrong some electrical components are different. i was going to test it but i have my doubts and i dont want to damage anything.
meanwhile i made a reset switch (temporary band aid) for the efi fuse with a NC switch if the CEL comes on i hit it and it goes away,is not an every day occurrence but in case it appears i dont have to pop the hood and take out the efi fuse, now i can make it from the inside.
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Old Oct 18, 2012 | 04:24 PM
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i thought the ecu was the same for the limited and sr5.

the limited uses the center plug on the ecu, while the sr5 does not, like mine.

i have a 2000 4runner engine.

Last edited by donomite49; Oct 18, 2012 at 04:25 PM.
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Old Oct 18, 2012 | 06:51 PM
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i was searching the web and found that ,different years different ecu
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Old Oct 10, 2015 | 06:08 PM
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Big update here
finally solved 3 years later!!!!

well today i finally fixed this electrical headache !! no more running pump while switch in on pos and now the obd reader works!!!

the culprit in my case was that the po bypassed the neutral safety switch by energizing the starter relay from the efi fuse so thats why the pump never stop priming and the obd port never worked ,so i undo the jumper and it works.
BUT!!! now it wont crank because theres no signal going to the starter relay wich means that maybe the neutral safety switch is cloged with dry grease or maybe the factory alarm which i removed was causing the problem,anyway im taking out the nss and clean it if this dont fix it im going to make a new line from ignition switch to starter relay and its done!!!

right now is starting great with a push button wired to the starter relay but i dont want to have that funky dance to start it.
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Old Oct 19, 2015 | 10:36 AM
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Finally working great
odb port working and starting via ignition switch,perfect!!!
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Old Oct 20, 2015 | 05:27 AM
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90% of the time it's a wiring problem. Glad you got it sorted.
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