My immobilizer fix (1 Viewer)

[medtro]

This kit would work on an 2006, right?

Yes.

Troubleshooting instructions for newer UZJ100/LX470, post #117.

 

[2006 LX470]

Yes.

Troubleshooting instructions for newer UZJ100/LX470, post #117.

Thank you for the super quick reply. I will keep some wire with me and try it next time I experience the no start issue. Appreciate it

 

[medtro]

Thank you for the super quick reply. I will keep some wire with me and try it next time I experience the no start issue. Appreciate it

You may want to practice how to remove the relay before hand. Some of them can be stubborn, may need some kind of picker to release the tab.

 

[Hokie99]

Have had mine in my sons 1998 Lc for 3.5 years, works flawlessly. Thanks a lot @medtro

 

[BullElk]

Have had mine in my sons 1998 Lc for 3.5 years, works flawlessly. Thanks a lot @medtro

You must have traded your avatar for his bypass kit.

 

[Jackland]

Seeking some clarification on the safety of going from the F terminal to the battery. This is currently the wife's daily, I don't need anything smoking, potentially damaging something else, etc. Anyone run it like this temporarily, like say a couple weeks or so and not had any issues? Thanks!!

 

[Exiled]

A good friend of mine bought his 2000 UZJ100 with the @medtro immobilizer kit already installed on it by the previous owner (who knows how long before the sales) and my buddy ran it for like six months like that with no issues. Not advocating these shenanigans, just passing along the experience!

 

[Jackland]

A good friend of mine bought his 2000 UZJ100 with the @medtro immobilizer kit already installed on it by the previous owner (who knows how long before the sales) and my buddy ran it for like six months like that with no issues. Not advocating these shenanigans, just passing along the experience!

Thx for your reply. I’ve got pretty high confidence in the “fix” cause basically it looks like we’re making new connections without paying $500 for a new box. Was curious about going direct to battery from the F terminal. Is this just intended to be an emergency kinda thing or am I ok letting the wife drive around with it like that until I can my hands on the kit?

 

[kevgentile]

Thx for your reply. I’ve got pretty high confidence in the “fix” cause basically it looks like we’re making new connections without paying $500 for a new box. Was curious about going direct to battery from the F terminal. Is this just intended to be an emergency kinda thing or am I ok letting the wife drive around with it like that until I can my hands on the kit?

You'd probably be ok if you ran a fused jumper short term, but it would require you to disconnect it after every cycle to prevent battery drain.
The traditional circuit energizes the relay once the key is inserted. With a jumper in place of the relay you're essentially providing a constant 12v with key out.

You can pull the fuse box out and repair it in an afternoon. I just did mine last week. It's a bit of a paint to separate the box so I dremeled out the retainers and used screws to refasten the halves. Worked out well and retained the oem set-up with no jumpers or bypasses.

 

[Jackland]

You'd probably be ok if you ran a fused jumper short term, but it would require you to disconnect it after every cycle to prevent battery drain.
The traditional circuit energizes the relay once the key is inserted. With a jumper in place of the relay you're essentially providing a constant 12v with key out.

You can pull the fuse box out and repair it in an afternoon. I just did mine last week. It's a bit of a paint to separate the box so I dremeled out the retainers and used screws to refasten the halves. Worked out well and retained the oem set-up with no jumpers or bypasses.

So what did your repair entail, just tightening up the receptacles (or whatever they are called) that the blades of the EFI relay go into?

 

[kevgentile]

So what did your repair entail, just tightening up the receptacles (or whatever they are called) that the blades of the EFI relay go into?

Went thru and crimped every terminal, swapped out the efi fuse terminals with 2 from one of the unused fuse blanks, and thru some solder in on the efi fuse terminals.

Only had a few terms that were loose but did them all as a precaution. The efi terminal "A" was the worst, which of course feeds the power to the relay. Didn't burn up anything but definitely had a very loose contact causing an intermittent voltage drop

 

[Jackland]

Went thru and crimped every terminal, swapped out the efi fuse terminals with 2 from one of the unused fuse blanks, and thru some solder in on the efi fuse terminals.

Only had a few terms that were lose but did them all as a precaution. The efi terminal "A" was the worst, which of course feeds the power to the relay. Didn't burn up anything but definitely had a very lose contact causing an intermittent voltage drop

Thanks!

 

[Jackland]

Bypass ordered, but couldn’t help myself…..jumper from F to battery, switched to stop the draw when off.

 

[DIRTBIKEUSA]

I got the famous crank but not start immobilizer problem. I replaced the 20A EFI fuse with a 30A fuse and it started right away. However, it was a temporary fix. I had the same problem again 4 days later. This is what I did to get the engine started. It has been working with no problem for close to 4 weeks now, I thought I would share this with the group.

Fuse terminals: A, B
EFI relay terminals: C, D, E, F

View attachment 1311409

With the EFI fuse in place and relay removed, I ran a wire from the battery positive terminal to terminal F, engine started with no problem. This tells me problem was at upstream or bad relay.

PS: This is a good wire to have in the car for emergency fix.

View attachment 1311410

Factory EFI relay tested good. Next, I shorted terminals E and F, engine cranked but not started. This tells me the power from terminal E was not good enough to start the engine. With the help of voltmeter, I found out there was 0.44V voltage drop between the battery and terminal E with factory 20A fuse in place. Voltage drop was 0.14V with 30A fuse. The engine wouldn't start even with 0.14V voltage drop. I came up with the following to bypass the internal circuit between terminals B & E in order to reduce the voltage drop between the battery and terminal F.

I used a Tyco V23234-A1001-X043 Mini Relay 12V. Make sure the relay you use has suppression protection if you are going to do this, otherwise this could cause damage to your ECM.

Wiring diagram:
Terminal A to 20A inline fuse to terminal 87 of Bosch relay
Terminal F to terminal 30 of Bosch relay
Terminal C to terminal 85 of Bosch relay
Terminal D to terminal 86 of Bosch relay
No connection for terminals B and E

Factory EFI relay can be used in this setup. I used Bosch relay because I want the relay to sit flat in the fuse box. I also put a piece of high density foam between the fuse box cover and Bosch relay to "secure" it better in place.

View attachment 1311417
View attachment 1311418

Dealing with this same issue now! Thank you kind member for forwarding me to it!

 

[Jackland]

Dealing with this same issue now! Thank you kind member for forwarding me to it!

Got this bypass last fall. No issues whatsoever of course. Yea, you can pull the box, repair it, or get a new one, but for me this was ideal given the cost/time between the two options. Dude shipped it pronto. Highly recommend.

 

[Bigjaytexan]

I agree that terminal B is bad. I was able to reduce the voltage drop by poking terminal B with sharp object.

I know this is old thread, but i have a 1998 Lexus lx470 and have drove it about 5k miles no issues, recently had a extra key cut and programed it worked to start etc, drove it about 50 miles since new key, (I'm still using the old key just wanted an extra key) drove it home the other day parked all good, then about hr later needed to leave again and no start, first thing i did was check for fuel not fuel when turning over, so figured the fuel pump went, bought a new delphi pump and replaced it, still no fuel, then hooked to obd2 scanner and no communication? checked fuses, all good? any ideas?

 

[Jackland]

I know this is old thread, but i have a 1998 Lexus lx470 and have drove it about 5k miles no issues, recently had a extra key cut and programed it worked to start etc, drove it about 50 miles since new key, (I'm still using the old key just wanted an extra key) drove it home the other day parked all good, then about hr later needed to leave again and no start, first thing i did was check for fuel not fuel when turning over, so figured the fuel pump went, bought a new delphi pump and replaced it, still no fuel, then hooked to obd2 scanner and no communication? checked fuses, all good? any ideas?

Have you done the tap tap on the EFI fuse? It sounds like the engine is cranking, correct? Just no start? I was able to prove the EFI fuse (the big dog) was an issue by removing it and installing a temporary jumper. I actually made my "loop" pretty big, ran it into the car and turned the switch on and off (so it wouldn't drain the battery) while I was waiting on this gentlemen's bypass thing. You can scroll back up through this thread, you'll see which terminals you put either end of your jumper in. If it cranks, you've identified your problem.

 

[medtro]

I know this is old thread, but i have a 1998 Lexus lx470 and have drove it about 5k miles no issues, recently had a extra key cut and programed it worked to start etc, drove it about 50 miles since new key, (I'm still using the old key just wanted an extra key) drove it home the other day parked all good, then about hr later needed to leave again and no start, first thing i did was check for fuel not fuel when turning over, so figured the fuel pump went, bought a new delphi pump and replaced it, still no fuel, then hooked to obd2 scanner and no communication? checked fuses, all good? any ideas?

How did you verify fuel pump is not working?

Will it start with starting fluid?

Do you have spark?

Do you have flashing security light while the engine cranks?

 

[Import Driver]

Yes.

Troubleshooting instructions for newer UZJ100/LX470, post #117.

About a month ago my 2006 had a no start issue. After about 5 minutes, it started right up. A week later, random no start. I went inside, started researching, 15 minutes I went back out and it started right up. Since then I've found the post "Troubleshooting instructions for newer UZJ100/LX470, post #117.", made a jumper wire to do the test once it happens again, and removed/reinstalled the relay just to make sure I could get it out. Then I waited for it to happen again... and waited... and waited...

FINALLY!!! Today no start in my driveway! I've never been so happy about a no start. I popped the hood, tapped the relay mentioned in post #117, and the truck started right up.

So I'm guessing its just a relay going bad? Does that make sense?

 

[medtro]

About a month ago my 2006 had a no start issue. After about 5 minutes, it started right up. A week later, random no start. I went inside, started researching, 15 minutes I went back out and it started right up. Since then I've found the post "Troubleshooting instructions for newer UZJ100/LX470, post #117.", made a jumper wire to do the test once it happens again, and removed/reinstalled the relay just to make sure I could get it out. Then I waited for it to happen again... and waited... and waited...

FINALLY!!! Today no start in my driveway! I've never been so happy about a no start. I popped the hood, tapped the relay mentioned in post #117, and the truck started right up.

So I'm guessing its just a relay going bad? Does that make sense?

Yes, it makes sense.