fix for immobilizer issue?

[Daniel Bare]

Continued from above...

6. Applied a couple pieces of marine grade heat shrink to the fuse holder leads.
7. Soldered the new fuse holder to the tinned tabs, this took some heat...
8. Heat up heat shrink.
View attachment 1311063

9. Job done, car fired right up!

Total time 1 hour, cost, $4.95.

Excellent work. I have the same recurring immobilizer/charred fuse issue as others, so I will be doing this within the week, as opposed to $400+ for a possibly discontinued fuse box that has an inevitable fatal flaw built in. Toyota should supply an upgrade for free as most 100s are hitting this fatal flaw prior to 300k miles, which is when LC’s are supposed to just be hitting puberty. Thanks for the pics too.

 

[sacman]

You should also double check the ground wire from the battery terminal. In my case, it's barely connected enough to unlock the car but when the starter started cranking, it's not enough contact to provide the high current demand.

 

[medtro]

You should also double check the ground wire from the battery terminal. In my case, it's barely connected enough to unlock the car but when the starter started cranking, it's not enough contact to provide the high current demand.

Is this before or after you tapped the starter relay?

 

[Tele65]

Thanks for the thread! Just had the same problem, corroded fuse. Will see if it reoccurs.

 

[BigZPatt]

No issues since last post. This past weekend, went deep into the Upper Greys River Road (40+ miles) with my Hundy and a pack of 20 amp fuses. Zero failure.

However, everytime I insert my key, I held my breath... Never had any immobilizer issues until 252K.
Had the classic throttle body, 2000 tranny issue, starter issue and now this...

I am contacting alarm installers in Denver and SLC to see if they can bypass the factory immobilizer.

Will keep everyone posted. Best Regards.

What was the 2000 Tranny Issue you referenced?

 

[harrislc100]

I’ve had my 01 LC for about a year now. (196k) a few weeks ago, I started having the crank/not start issue. Looked on here and saw the immobilizer issues. Found out pretty quickly that it is definitely the immobilizer. Took it to my shop and the easiest/most reliable fix is to replace the fuse box. I hate spending the $$ but I’m happy to know that’ll fix it.

 

[Unca Charlie]

I’ve had my 01 LC for about a year now. (196k) a few weeks ago, I started having the crank/not start issue. Looked on here and saw the immobilizer issues. Found out pretty quickly that it is definitely the immobilizer. Took it to my shop and the easiest/most reliable fix is to replace the fuse box. I hate spending the $$ but I’m happy to know that’ll fix it.

I guess I'm the only one that didn't have to replace the fuse box for this issue. Odd that I'm the only one that had the signal amplifier go out on the jgnition assembly. $120 fix. Sure glad I didn;t replace the fuse box first.

 

[aedavis]

Update: I'm the original poster here, and I've had my 2001 LC jumpered with a spade connector since 2013. It hasn't given me any further issues. It currently has 225,000 miles.

 

[steelefuegen]

Update: I'm the original poster here, and I've had my 2001 LC jumpered with a spade connector since 2013. It hasn't given me any further issues. It currently has 225,000 miles.

How did you set up the jumper? I'm new to a lot of electrical fixes and I am confused as to what the jumper is and how it is set up in place of the fuse? Do you have and pictures? Thanks for the help!

 

[aedavis]

How did you set up the jumper? I'm new to a lot of electrical fixes and I am confused as to what the jumper is and how it is set up in place of the fuse? Do you have and pictures? Thanks for the help!

I'm using a spade connector in place of the 20 amp EFI fuse - one of these:



In case this spade connector / jumper ever stopped working, I rigged a wire from the positive battery terminal that I can plug into the EFI fuse location, to provide 12V directly to the fuse, but I haven't had to use it yet since the jumper has been working. In the following picture, you can see the jumper wire hanging off the positive terminal in the upper left (large yellow circle), and on the bottom left of the picture (in the small yellow circle) is the jumper/spade plugged into the fuse block, in place of the EFI fuse.

 

[HRTROB]

I just experienced this problem on my '02 LX. First symptom was the engine died while I was backing out of the driveway while shifting the transmission from R to D. It started then died again. After the second re-start it ran fine. I have an old battery in there and thought the voltage drop might have caused the engine to stall so I charged it and it ran fine for a couple of days. Then today it wouldn't start, it cranks forever but wouldn't turn over. A quick search here on Mud pointed me to the EFI fuse. The immoblizer light was blinking so I knew it was either the key or the fuse. When I pulled the fuse off, one leg was black and the plastic was slightly melted. The female side where this blacked fuse leg goes to (the side closest to the fender) looked oxidized as well, while the other side (closest to the engine) looked pristine. I tried to add tension to the contacts using a small flat blade screwdriver, but the plastic "neck" or tower that surrounds the fuse slot snapped around the area near the fender side slot, indicating that the plastic might have gotten brittle due to the heat on that side of the fuse.

Anyway I went ahead and put in a fresh 20A fuse and it started right up. But as soon as I wiggled the fuse, the engine died. Right now I added some more tension on the contacts and the engine no longer dies when wiggling the fuse. I'll have to do a more permanent fix though because this problem is a huge safety issue and I'm very lucky the engine didn't die yesterday while I was driving on the highway. The bypass method with a new relay and fuseholder won't work for me since the side that the kit plugs into is the problematic side on mine. I'm thinking of removing the neck and tabs completely to expose the metal prongs, then instead of soldering a fuse holder onto those prongs, I'd solder the fuse holder leads to two spade connectors that will insert into the metal prongs in the fuse box. Do you guys think this is a good idea or should I just solder directly to the prongs?

 

[HRTROB]

Okay so I managed to pull out the bad fuse contact from the fuse terminal. I believe this is the constant +12V side. As mentioned in my previous post, the contact on the other side looked pristine so I left it alone. I cleaned the bad contact as best I could including the prong on the fuse box itself and went for a test drive. The engine doesn’t stall when wiggling the fuse, but after a 10 minute drive the fuse contact was very hot, indicating high resistance. I ended up soldering together two fuse holder contacts that I ripped apart from a universal mini fuse holder. One side to grab onto the prong on the fuse box, and the other for the fuse. It worked, that side of the fuse no longer gets hot at all even after a 20 minute drive.

Fuse contact removed from fuse box.

New contact installed. Made up of two female fuse holder contacts soldered together. It no longer gets hot when car is running.

 

[johnschell]

Looks like it's my turn on this merry-go-round. Had the immobilizer issue happen in February 2020, but at the time I didn't know what it was - just that my 2004 / 245k mostly all-stock LC wouldn't start. The engine would crank, but never fire up. We were in a parking garage and at the time I thought it might have been the battery, the starter, or the security system. Fortunately, after about an hour or so, it started back up and we drove home, seemingly to forget about the issue, even taking the LC cross country and up to the PNW since then.

Yesterday morning, I was on my way out the door for an appointment, and lo and behold, the same issue. I waited it out for a couple minutes, tried again, but since I was risking being late, I borrowed my SO's car and left. Got home later in the morning, tried it again and nothing. Battery is three months old, so that isn't it. Gas tank is 1/2 full, fuel pump seemingly turns on, etc. CEL light, all dash lights look normal. Code reader said I had an EVAP issue, but I think the might be from the last time I read the code, before I replaced the O2 sensor last year... I cleared it and it hasn't returned.

Only "work" I had done recently was changing the oil on Monday and greasing the U-joints, etc last weekend.

Anyhow, I pulled up mud and went to town reading up on the immobilizer issue. And here I am.

I have a 25 amp fuse in the EFI slot, which I am going to replace with a 30amp today. Going to check the gas cap. Going to leave the key in the ignition to the ON position for 15 minutes. I am dreading taking it to a mechanic because everything I've read here suggests that non-specialized mechanics misdiagnose the issue to the tune of hundreds or thousands of dollars.

If all else fails, I am going to put a paperclip in the fuse position and cross my fingers.

Will update ASAP.

 

[highonpottery]

Knocking on wood as I mention this, but I haven't had this issue come up on our Cruiser since 2016. The last time it happened, all I did was take pliers and bend the 20A fuse prongs just a tiny bit, so they had more tension for better contact. Hopefully something simple like that can get others going again when this happens. Good luck everyone.

 

[johnschell]

Looks like it's my turn on this merry-go-round. Had the immobilizer issue happen in February 2020, but at the time I didn't know what it was - just that my 2004 / 245k mostly all-stock LC wouldn't start. The engine would crank, but never fire up. We were in a parking garage and at the time I thought it might have been the battery, the starter, or the security system. Fortunately, after about an hour or so, it started back up and we drove home, seemingly to forget about the issue, even taking the LC cross country and up to the PNW since then.

Yesterday morning, I was on my way out the door for an appointment, and lo and behold, the same issue. I waited it out for a couple minutes, tried again, but since I was risking being late, I borrowed my SO's car and left. Got home later in the morning, tried it again and nothing. Battery is three months old, so that isn't it. Gas tank is 1/2 full, fuel pump seemingly turns on, etc. CEL light, all dash lights look normal. Code reader said I had an EVAP issue, but I think the might be from the last time I read the code, before I replaced the O2 sensor last year... I cleared it and it hasn't returned.

Only "work" I had done recently was changing the oil on Monday and greasing the U-joints, etc last weekend.

Anyhow, I pulled up mud and went to town reading up on the immobilizer issue. And here I am.

I have a 25 amp fuse in the EFI slot, which I am going to replace with a 30amp today. Going to check the gas cap. Going to leave the key in the ignition to the ON position for 15 minutes. I am dreading taking it to a mechanic because everything I've read here suggests that non-specialized mechanics misdiagnose the issue to the tune of hundreds or thousands of dollars.

If all else fails, I am going to put a paperclip in the fuse position and cross my fingers.

Will update ASAP.

Couple of self updates..The fuses came in so I went and replaced the EFI 25amp with the 30amp and literally nothing changed. However, having my SO in the cab to turn the key led me to something else which I didn't noticed earlier - there is a spinning / whining noise coming from around mid-engine just next to the steering column. It's difficult to describe the sound, but seems like something is just spinning and/or not connecting? I don't know - my knowledge starts to run thin here. This sound was only on when the key was in the ON position and seemed to stop when it was cranking. I think.

this link should go to the quick video I recorded of the sound. LC 100 SOUND

In addition, I noticed that the security light shuts off as I expect it should, so assuming that rules out the EFI / Immobilizer issue.

Any help / guidance would be greatly appreciated.

Thank you!

 

[johnschell]

Update. Still DOA. Cranks strong but nothing else for over a week now. Disconnect battery negative - nothing. Disconnected the positive and when I connected it, I got what I thought was a start, but nothing came of it and it went back to crank no start..

Narrowing it down further the only thing I did differently, was that on Sunday, I filled up the tank for the first time since June and had my tires rotated the week before last. Nothing else.

 

[flintknapper]

Update. Still DOA. Cranks strong but nothing else for over a week now. Disconnect battery negative - nothing. Disconnected the positive and when I connected it, I got what I thought was a start, but nothing came of it and it went back to crank no start..

Narrowing it down further the only thing I did differently, was that on Sunday, I filled up the tank for the first time since June and had my tires rotated the week before last. Nothing else.

So....IF the security light goes out immediately when you insert the key AND it doesn't blink when cranking the engine then you don't have an immobilizer issue related to the fuse box.

My inclination would then be to check fuel pressure. The fuel pump does NOT run on these vehicles until the engine is cranking, so by installing a banjo bolt adapter you could then use a fuel pressure gauge to check and see what (if any) pressure you have. You need a minimum of about 45 psi.

Instead of fitting an adapter...I opted to just install a good quality mechanical pressure gauge and leave it in place.

 

[medtro]

Update. Still DOA. Cranks strong but nothing else for over a week now. Disconnect battery negative - nothing. Disconnected the positive and when I connected it, I got what I thought was a start, but nothing came of it and it went back to crank no start..

Narrowing it down further the only thing I did differently, was that on Sunday, I filled up the tank for the first time since June and had my tires rotated the week before last. Nothing else.

Do you have spark? Try starting with starting fluid if you have spark.

 

[johnschell]

So....IF the security light goes out immediately when you insert the key AND it doesn't blink when cranking the engine then you don't have an immobilizer issue related to the fuse box.

My inclination would then be to check fuel pressure. The fuel pump does NOT run on these vehicles until the engine is cranking, so by installing a banjo bolt adapter you could then use a fuel pressure gauge to check and see what (if any) pressure you have. You need a minimum of about 45 psi.

Instead of fitting an adapter...I opted to just install a good quality mechanical pressure gauge and leave it in place.

View attachment 2848932
View attachment 2849005

Thanks for the response - yes, based on what I've read in the threads posted about the issue, everything I'm experiencing points away from the immobilizer / fuse / fusebox being the issue and more toward the fuel pump (security lights, CEL / Dash Lights, and and replaced fuses, etc)

Adding the fuel pressure gauge is a bit above my ability at the moment, not to mention, living in Los Angeles, mine is parked on a relatively busy street, across the street, and a couple of houses down, so it's not an idea place to get any good work done at the moment.

 

[johnschell]

Do you have spark? Try starting with starting fluid if you have spark.

Unfortunately, this is where my knowledge wears thin - if I had to guess, I'd venture that I have spark as the truck has been running flawlessly since the day I got it (with only that one hiccup I mentioned above which happened for an hour, nearly two years ago), even taking it on a 200 mile round trip drive Sunday and it starting up no problem Monday morning when I had to move it out of the street sweeping zone... but that's the confusing part. No signs of anything wrong, even keeping with 15mpg on the highway the entire time.

That said, I will be heading to AutoZone tomorrow to pick up some starting fluid.

Other that that, any idea what could cause it to stop so suddenly? I'd always assumed that if a pump is failing, it'll happen over time and not on one day and off the next, literally 16 hours later with no signs and no use in between. I almost suspect that fact that since I filled the tank for the first time since June (my driving is very limited so 50-60 bucks to get me to 1/2 a tank every couple of weeks is normal), I'd inadvertently kicked up some debris in the tank which clogged the filter, but when I attempted to start it this past Tuesday, it didn't even sputter - it just wouldn't start in the same way it's not starting now. Nothings changed since the first attempt. So I just assume something died. But I have no idea what.

Also, I almost wish it was the relay because your bypass comes so highly rated and looks like such a slick piece of DIY engineering. I might actually pick one up anyway, to keep in my toolbox.

Thanks so much for your help