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Okay so I was having issues with my ls400 before but I think I solved them and then made it a million times worse lol. I ended up getting an ecu replacement bc mine was beyond repair (leaking capacitors and missing races or traces or whatever they’re called. Then I tried jumping my car and I accidentally jumped it with 55 *****ing volts please do not ask how just help me please. Now I keep blowing fuses. I blew a multitude in the fuse box in the car and the efi fuse in the engine fuse box. I replaced the blown ones and now I just keep blowing 3 fuses:
Radio no. 2
efi fuse
ign fuse
when I take the efi relay out I do now blow the efi fuse but still blow the ign and radio no. 2 fuses.
help!!!!
That's a touch situation you're going to have to unplug modules and/or connectors throughout the car until you isolate the what is causing the short. Disconnect the battery and put an ohm meter on the battery cables, keep checking the resistance as you are unplugging things.
Going to be a challenge figuring this one out. Best bet is to get comfortable with a multimeter and electrical prints for your car. Looking through your past post I saw you mention a 94 so I looked at prints based off of that. I'm also assuming that when jumping you attempted to start the car with that voltage level. Are the fuses popping as soon as you put them in or with the key in a certain position? The prints I'm looking at are kind of blurry so I cant make out all the details. For the EFI fuse the main item that goes to is the fuel pump ecu. Removing the relay and it not blowing pretty much narrows it to that. Radio no. 2 feeds the radio, amp, auto antenna, power mirror switch and mirrors, air conditioning. IGN goes to the airbag sensor assembly, a charge warning light, and the ECU. If im reading the prints right the radio2 fuse should be popping when you turn the key to accessory. The other two should only blow when the key is in the on position.
Could try pulling all of the fuses that were blown originally out, if you remember them, and put them back one at a time checking to see if / when one pops as that will likely be a circuit with an issue on it. Honestly you probably took out a bunch of stuff and might be in for a hell of a fix.
As is the diagram below, those 3 fuse lines are all connected to reverse polarity protection diodes in each units. The fuse Radio No. 2 is supplying +B to the audio units. Both EFI and IGN fuses are supplying +B to the ECU.
All these units have protection diodes which pass through the reverse current and are damaged when the battery is reversed. A skilled guy would fix those replacing diodes and also fix the related circuits but dealers just replace units and charge the customer some big $$$.
That's a touch situation you're going to have to unplug modules and/or connectors throughout the car until you isolate the what is causing the short. Disconnect the battery and put an ohm meter on the battery cables, keep checking the resistance as you are unplugging things.
what am I looking for when testing the resistance? Like is there a specific range it’s supposed to be?
Going to be a challenge figuring this one out. Best bet is to get comfortable with a multimeter and electrical prints for your car. Looking through your past post I saw you mention a 94 so I looked at prints based off of that. I'm also assuming that when jumping you attempted to start the car with that voltage level. Are the fuses popping as soon as you put them in or with the key in a certain position? The prints I'm looking at are kind of blurry so I cant make out all the details. For the EFI fuse the main item that goes to is the fuel pump ecu. Removing the relay and it not blowing pretty much narrows it to that. Radio no. 2 feeds the radio, amp, auto antenna, power mirror switch and mirrors, air conditioning. IGN goes to the airbag sensor assembly, a charge warning light, and the ECU. If im reading the prints right the radio2 fuse should be popping when you turn the key to accessory. The other two should only blow when the key is in the on position.
Could try pulling all of the fuses that were blown originally out, if you remember them, and put them back one at a time checking to see if / when one pops as that will likely be a circuit with an issue on it. Honestly you probably took out a bunch of stuff and might be in for a hell of a fix.
exciting thank you. This car has been a never ending problem for me (this one’s definitely my fault tho lmao)
Going to be a challenge figuring this one out. Best bet is to get comfortable with a multimeter and electrical prints for your car. Looking through your past post I saw you mention a 94 so I looked at prints based off of that. I'm also assuming that when jumping you attempted to start the car with that voltage level. Are the fuses popping as soon as you put them in or with the key in a certain position? The prints I'm looking at are kind of blurry so I cant make out all the details. For the EFI fuse the main item that goes to is the fuel pump ecu. Removing the relay and it not blowing pretty much narrows it to that. Radio no. 2 feeds the radio, amp, auto antenna, power mirror switch and mirrors, air conditioning. IGN goes to the airbag sensor assembly, a charge warning light, and the ECU. If im reading the prints right the radio2 fuse should be popping when you turn the key to accessory. The other two should only blow when the key is in the on position.
Could try pulling all of the fuses that were blown originally out, if you remember them, and put them back one at a time checking to see if / when one pops as that will likely be a circuit with an issue on it. Honestly you probably took out a bunch of stuff and might be in for a hell of a fix.
what do I check for the ign fuse? I’m mainly focused on efi and ign and I unplugged the efi relay and the efi fuse did not blow.
what do I check for the ign fuse? I’m mainly focused on efi and ign and I unplugged the efi relay and the efi fuse did not blow.
With how the issue started I would probably unplug everything from the ecu and see if the fuse pops then. Checking resistance values with a meter through all 3 circuits is going to be the only way to track the issues down. To be blunt with you, the 3 circuits your having trouble with all supply power to something with fairly sensitive electronic components. Hitting them with more than 4 times their rated voltage has likely fried multiple items and will probably need someone very skilled to find and correct everything.
02-02-24, 07:34 PM
Keeps blowing fuses
