My immobilizer fix (3 Viewers)

[medtro]

Is the most complete fix to replace the entire fuse box?

In my opinion, both are complete fix. The first kit I built is still in the LX470 since 2016. More info in post #5.

 

[kuhyuan]

1999 kx470. 160K. Original owner

cranks strong but will not start, the Immobilizer light blinks with the key in ignition.

tried jumping battery positive to F terminal. Would not start, just cranks. Battery is strong and everything does work. No CEL lights. Was working fine and was parked in the drive way overnight and would not start the next day.

did get a p1600 code after doing the F terminal wire jump.

am I missing something? Is the wire gauge too small or the spade connector not making full contact?

any help is appreciated

 

[gregnash]

If the immobilizer light is still blinking with the key in the ignition then it is not programmed to the system. You need to program the fob/transponder to the system to get it to be able to crank otherwise it is considered an unrecognized key and thus they system does a starter kill on it (crank but no fire).

 

[medtro]

1999 kx470. 160K. Original owner

cranks strong but will not start, the Immobilizer light blinks with the key in ignition.

tried jumping battery positive to F terminal. Would not start, just cranks. Battery is strong and everything does work. No CEL lights. Was working fine and was parked in the drive way overnight and would not start the next day.

did get a p1600 code after doing the F terminal wire jump.

am I missing something? Is the wire gauge too small or the spade connector not making full contact?

any help is appreciated

Make sure the jumper wire has good connection to F terminal. You can hold the wire to F terminal and have a helper to check for blinking light or turn the key.

Make sure it is connected to F terminal. A few people has connected the jumper wire to a different terminal.

As for P1600, did you remove the EFI fuse? If not, it pointed to your EFI circuitry in the fuse box is fubar. Jumping it like this should not trigger P1600.

 

[medtro]

If the immobilizer light is still blinking with the key in the ignition then it is not programmed to the system. You need to program the fob/transponder to the system to get it to be able to crank otherwise it is considered an unrecognized key and thus they system does a starter kill on it (crank but no fire).

There is other reason for blinking light with programmed key too.

 

[gregnash]

There is other reason for blinking light with programmed key too.

For whatever reason I missed that he was attempting to jump the system via the F terminal, bypassing the immobilizer. May be a candidate for a new fuse box.. Look up "ChowCares" on YouTube, he's got a 99 LC that he recently posted a video on doing this because he had the intermittent problem of this happening. When he dissected the old box, he found that the terminal connections for the EFI were loose inside the box (not like rattling around loose) and were just loose enough that over time they corroded and melted the bits around them causing the short. No posted issues since he put in the new box, which looks to be all of a job, at the cost of about $450 for the new box.

 

[medtro]

For whatever reason I missed that he was attempting to jump the system via the F terminal, bypassing the immobilizer. May be a candidate for a new fuse box.. Look up "ChowCares" on YouTube, he's got a 99 LC that he recently posted a video on doing this because he had the intermittent problem of this happening. When he dissected the old box, he found that the terminal connections for the EFI were loose inside the box (not like rattling around loose) and were just loose enough that over time they corroded and melted the bits around them causing the short. No posted issues since he put in the new box, which looks to be all of a job, at the cost of about $450 for the new box.

I am pretty sure shorting is not the problem here.

The purpose of this thread is to fix the same problem without paying $450.

 

[kuhyuan]

Thanks for the help

Also any chance that the crankshaft position sensor may have gone bad?

That oem part is close to. $100

Don't want to waste money on parts that doesn't need replacing.

Can't get any trouble codes on my code reader other than the P1600 after I did the F terminal bypass.

There were no problems of any sort before parking the cruiser.
I'll take a another look at it tomorrow

 

[medtro]

Thanks for the help

Also any chance that the crankshaft position sensor may have gone bad?

That oem part is close to. $100

Don't want to waste money on parts that doesn't need replacing.

Can't get any trouble codes on my code reader other than the P1600 after I did the F terminal bypass.

There were no problems of any sort before parking the cruiser.
I'll take a another look at it tomorrow

Do you still have blinking light with key inserted and jumped to terminal F?

Crank position sensor can go bad and not start the car but that is separate from blinking light with key inserted. I have brand new Toyota crank position sensor if you want it for less than $100 or dealer price.

 

[kuhyuan]

I do remember the blinking light was on when I was trying to start the engine but another time it wasn’t on. Idk if it was doing it while I had the jumper wire attached.
I’ll get my dad to help me when I try the jumper wire again, I did take out the EFI fuse when I did it the first time
It’s at my parents house and I’ll try to look at it tomorrow or Saturday. Definitely will take your offer, if I do actually need a crankcase sensor

Thanks

 

[kuhyuan]

Just a update, it was a bad fuel pump. Not a Immobilizer issue.

thanks for everyones help

 

[maxbob002]

Just wanted to say thanks for posting this information. Bypassed the fuse box with the stock relay today and cranked fine.

 

[pawwright]

Do you still have blinking light with key inserted and jumped to terminal F?

Crank position sensor can go bad and not start the car but that is separate from blinking light with key inserted. I have brand new Toyota crank position sensor if you want it for less than $100 or dealer price.

I'm interested - can you PM the price, please?

 

[99cruiserr]

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

So would this relay/fuese issue make it crank and run sometimes, but not others? Sometimes my 99 LC will crank perfect, but other times I'll have to cycle the key 3-4 times. Sorry if this is the wrong spot for this question. Im new to the forum and still trying to navigate. THanks!!

 

[medtro]

So would this relay/fuese issue make it crank and run sometimes, but not others? Sometimes my 99 LC will crank perfect, but other times I'll have to cycle the key 3-4 times. Sorry if this is the wrong spot for this question. Im new to the forum and still trying to navigate. THanks!!

If you have crank and no start then the answer is yes.

 

[sacman]

I'm dealing with this issue right now but I can't find the pin diagram of the relay on my lexus 2003 LX470. The relay is ECD Main relay by Toyota 85915-30050/056700-7430 12V Denso

 

[medtro]

I'm dealing with this issue right now but I can't find the pin diagram of the relay on my lexus 2003 LX470. The relay is ECD Main relay by Toyota 85915-30050/056700-7430 12V Denso

It has been a while since I looked at one. Is there not a diagram on the relay?

 

[sacman]

There's a diagram but what I'm looking for is the pin diagram of the ECD relay.

 

[medtro]

There's a diagram but what I'm looking for is the pin diagram of the ECD relay.

Not sure what you are looking for if the diagram doesn't answer your question. Did you check the PM I sent you?

 

[joshuatarr]

Yes, once the p1600 code is fixed thanks again to your advice.

Hey Team P1600 -

Looking for some advice....

I have the '03 LX470 with an immobilizer bypass.

I recently installed a Group 49 Duracell battery from Sams, I really liked how it was bigger and more CCA's, etc, etc, even tho it wasn't the recommended battery.

After installing, the check engine light came on, later diagnosed as the P1600/ECM/Battery/EFI Fuse issue.

I cleared the code (like a dozen times) but it keeps coming back.

After reading through all the posts here (also like a dozen times and coloring all the photos I printed out), I think I need the same fix as @lexs470 had, which seems to be suppling 12V to Block E, which is currently blank on my rig.

Where should I rig the power from for the E terminal?

My hypothesis is that the 'stronger/newer' battery finished burning through the faulty fuse block taking out Terminal E which wasn't a problem previously. Is this plausible?