My immobilizer fix (2 Viewers)

[4WDarren]

@medtro Just wanted to say thank-you for starting this thread! Once again, I am indebted to the fine folks on this forum for such resources.

Recently had this issue on my 2001 LX at 153,000 mi. 20A fuse was not blown, but before I pulled it out to inspect further, I gave it (and the relay) a little wiggle & push and sure enough, she fired right up. From the top side, the relay and fuse connections all looked fine, everything still fits tight, no burn marks, etc. Based on this thread, I guess the issue lies deeper within the box, but I really don't feel like ripping it apart, or spending the $700 for a new one.

Not sure how long it will take to happen again, but I think I'll be putting in an order or making my own to have on hand when it does!

 

[kelly saad]

Yes, power source.

Will this cause the check engine light to turn on? My terminal eventually went bad, so I ran it directly to the battery, and immediately the engine light came on. Any ideas?

 

[medtro]

Will this cause the check engine light to turn on? My terminal eventually went bad, so I ran it directly to the battery, and immediately the engine light came on. Any ideas?

Start reading from post #70 if you are getting P1600 code.

 

[medtro]

Connecting it to battery will not cause check engine light to turn on. My guess is you have P1600 code after reviewing your picture. Fused 12V to E should take care of the problem.

 

[RoughOne]

Been over 3 years since My Immobilizer issue. My Fix which cost a couple dollars (small power wire) is holding up just fine! Ghetto rigged with No battery drain issues whatsoever.

 

[udubfl]

Well, my 01 LC (213k) started and died at a tire shop when they were trying to drive it up to the lift. It was cranking but no start. Had it towed back to my house this afternoon and went through the diagnostics.

I think I figured it out for now. 20amp EFI fuse was basically melted in its place. Had hard time taking it off but eventually it did. EFI relay seems okay (did the Medtro test) for now. So, I have ordered a new fuse box (82720-60023) along with a new EFI relay (85915-30050) from dealership. My wife drives this one and soon my kiddo will be driving it, so didn't want this thing to fail on them and figured it would be good for another 200K.

In the meantime, I am reusing the EFI relay until I can install the new parts. Since terminal A is unusable, I went ahead and connected it directly to the battery. LC started when testing it. So, will check up on it tomorrow. As always, appreciative of this forum.

Color coded my wires because it just helps me see it better from one end to another end

Had to cut out a slot in the fuse box so that the hot wire didn't get kinked. Wrapped it in wiring tape to give a little more protection from vibration. Figured i'm tossing this box next week so cutting it a little won't hurt. Having an existing screw wing-nut made it simple to connect to battery.

 

[BullElk]

I am curious. Did this work?

After nearly a year, I can now confirm that No SIr, this contraption by the previous owner did not prevent the EFI fuse from melting this evening. I just finished the permanent fix for this as I did for my other 2000 LX.........Thanks to the help from @medtro.

 

[thetoyotaman]

Thanks @medtro for this thread. Our 2000 LX470 wouldn't start this afternoon so I performed the test from battery to F terminal to confirm the problem and then with some wiring supplies in the garage wired up the relay as outlined. Thank you!!!!

 

[YungTexx]

I have read the thread from the very beginning and would like to thank this entire community for amazing expertise and values.

My issue:

I have not run any diagnostics but my (new) 1999 LC with 265k miles cranked but no start this morning (2/8/22). I have put 1000 miles on it in 2 weeks after buying in Tennessee and driving home to Texas.

Over the week I have observed a few electrical issues but deemed them nothing major.

Observations:
1) EFI made violent and consistent clicking noise one day after turning car off and locking. This happened a week ago and never happened again.
2) Two nights ago battery light and abs light came on after 1mile round trip to store and home. Radio also flicked on and off repeatedly and headlights dimmed.
3) truck has once or twice “beeped” at me as if key is still in ignition or head lights are still on after beginning to exit.

Things I know: fuel pump has been replaced least year along with spark plugs and coils. Battery is 2020 and has plenty of voltage (unsure on exact amount)

I have used this a daily since acquiring but I let it sit for a day after the battery light and abs light scared me Sunday evening. I originally thought it was an alternator issue and had appointment this morning for fort worth Texas LC specialist to see (but alas I never made it) so, like I said, let it sit for a day.

Any reason to believe this is a bigger issue than just EFI?

 

[YungTexx]

I have read the thread from the very beginning and would like to thank this entire community for amazing expertise and values.

My issue:

I have not run any diagnostics but my (new) 1999 LC with 265k miles cranked but no start this morning (2/8/22). I have put 1000 miles on it in 2 weeks after buying in Tennessee and driving home to Texas.

Over the week I have observed a few electrical issues but deemed them nothing major.

Observations:
1) EFI made violent and consistent clicking noise one day after turning car off and locking. This happened a week ago and never happened again.
2) Two nights ago battery light and abs light came on after 1mile round trip to store and home. Radio also flicked on and off repeatedly and headlights dimmed.
3) truck has once or twice “beeped” at me as if key is still in ignition or head lights are still on after beginning to exit.

Things I know: fuel pump has been replaced least year along with spark plugs and coils. Battery is 2020 and has plenty of voltage (unsure on exact amount)

I have used this a daily since acquiring but I let it sit for a day after the battery light and abs light scared me Sunday evening. I originally thought it was an alternator issue and had appointment this morning for fort worth Texas LC specialist to see (but alas I never made it) so, like I said, let it sit for a day.

Any reason to believe this is a bigger issue than just EFI?

Also should be noted. I have spoken to PO is 2nd owner and I have no reason to believe he is lying when he said a crank but no start issue has never happened (but still skeptical)…

Another thing to consider: On my purchase date and first day road trip home I drove through 5 hours of torrential downpour but observed ZERO issues my second day of driving in dry condition other than a loud clicking in radio head unit.

 

[YungTexx]

Also should be noted. I have spoken to PO is 2nd owner and I have no reason to believe he is lying when he said a crank but no start issue has never happened (but still skeptical)…

Another thing to consider: On my purchase date and first day road trip home I drove through 5 hours of torrential downpour but observed ZERO issues my second day of driving in dry condition other than a loud clicking in radio head unit.

apologies, should also be noted that the security light next to the clock blinked red this morning while cranking.

I’m wondering if this is all connected or separate issues.

 

[medtro]

apologies, should also be noted that the security light next to the clock blinked red this morning while cranking.

I’m wondering if this is all connected or separate issues.

I think the culprit is 5 hours of torrential downpour. You may have water intrusion. If you still have this blinking security light after all the fuse blocks dried up, then you may need this fix.

 

[YungTexx]

I think the culprit is 5 hours of torrential downpour. You may have water intrusion. If you still have this blinking security light after all the fuse blocks dried up, then you may need this fix.

Perhaps. However, it has been one week of dry and 70+ degrees with daily commuting.

Upon reading this entire thread, I will try using the nonelectric key and perform voltage tests this evening and return.

Can we go ahead and move forward with purchasing the kit anyways? I’ve read too much to think my cruiser is immune in any way. Thank you.

 

[medtro]

Perhaps. However, it has been one week of dry and 70+ degrees with daily commuting.

Upon reading this entire thread, I will try using the nonelectric key and perform voltage tests this evening and return.

Can we go ahead and move forward with purchasing the kit anyways? I’ve read too much to think my cruiser is immune in any way. Thank you.

If you think it is dry enough, please follow troubleshooting instructions in post #51. This is not a valid test if your security light doesn't flash while engine cranks.

 

[bangbang001]

@medtro I have an 02 Lx and today I got no start after I parked and tried to start up. Security light stays on while cranking but no start. I removed the ECD main relay and ran a wire from the battery to D accidentally instead of F and the truck started. I then tried to jump E and F and it cranks but no start, I also tried a wire from the battery to F and no start but cranking and security light was on while cranking. When jumping E And F should you still use a wire from battery to F also? The truck will start with a wire from battery to D, what should I do next? Can I drive around without the relay and have a wire from the battery to D?
Thanks for any advice.

 

[medtro]

@medtro I have an 02 Lx and today I got no start after I parked and tried to start up. Security light stays on while cranking but no start

Did the the security light flash or stay on?

I removed the ECD main relay and ran a wire from the battery to D accidentally instead of F and the truck started. I then tried to jump E and F and it cranks but no start, I also tried a wire from the battery to F and no start but cranking and security light was on while cranking.

It looks like you may have a new variant or delta problem. Is the "Check Engine Light" on with key at ON position (do not start) and:

• stock fuse and relay inserted?
• relay removed, wire from battery connected to F?

When jumping E And F should you still use a wire from battery to F also?

No need to have wire from battery when jumping E & F.

The truck will start with a wire from battery to D, what should I do next? Can I drive around without the relay and have a wire from the battery to D?
Thanks for any advice.

I don't know why it starts with wire connected to D. I guess your next step is to figure out why it starts with wire connected to D. There is no fuse protection with connection like this, bad thing can happen with no fuse protection. Drive at your own risk. Disconnect wire to D when engine is shut off if you choose to drive it.

 

[tkorade]

After much troubleshooting on my 2004 100 series I have another resolution to the crank no start.
Used truck new to me after 3 owners, last one was a construction company with 235000 miles.

Problem started and the initial indication was loss of programing for the keys. After doing the all key lost procedure and re adding the keys in truck ran fine for months.

Did the crank no start again and I was able to get the immobilizer resynced by doing the lock the truck from the inside close the door and use the master key to unlock from the drivers side holding the key in the unlock position for 30 seconds. At this point the truck ran but the ECU still had a B2796 No Communication in Immobilizer System and could not be cleared.

Week later crank issue again and the system could not be programed. So pulled the whole dash apart to get to the immobilizer and replaced it (no sign of water intrusion around the immobilizer). Programmed all the keys and the truck worked for about 10 starts and then the B2796 again, immobilizer was fried.

Started tracing wires found most run to cowl side junction block (p/n 82731-60060) and that had corrosion inside the block. Replaced the block and the immobilizer, reprogramed the keys and everything is working great.

My working theory is after looking at the windshield it is not a factory Toyota one. Broken and it allowed rain to intrude then replaced or the replacement is not sealed correctly? Shopping around for a good glass place around us and will probably have it replaced so I know it is done right.
I hope this can help out others with this symptom.

 

[medtro]

Week later crank issue again and the system could not be programed. So pulled the whole dash apart to get to the immobilizer and replaced it (no sign of water intrusion around the immobilizer). Programmed all the keys and the truck worked for about 10 starts and then the B2796 again, immobilizer was fried.

Can you please post the immobilizer part number?

 

[harrydunn]

Not quite the same model number but I believe this relay will work like the x043? Trying to research if it has suppression protection.

Amazon product ASIN B079BKHX82

 

[harrydunn]

Disregard. I'm not seeing a diode in the schematic for the 036.