My immobilizer fix (3 Viewers)

[70 FJ40]

So problem has continued to be intermittent but on Monday night it lasted long enough for me to take more voltage readings and I was only getting 8.6 volts from terminal A. So now I have taken fused power directly from the battery and it seems to be working well since.

 

[850dualcab]

Hi, I have read this thread front to back.
I have had similar issues to everyone here but mainly the EFI fuse melting (poor connection at B).

I pulled the relay and checked it - seemed ok - after reading this not so sure. But in checking everything out I have found that I now have no voltage at the switching terminal of the relay (D terminal in Medtro's diagram)
Beats me - where do I start??

 

[lexs470]

So here's something to ease these diagram and wirings:

Going by the 2 terminals A and B of the fuse, and 4 terminals of the relay as per the attached diagram (fusebox1), this is what they correspond to:
A: Gets constant power , +12V : connect this to new relay pin 87
B: Gets constant power but gets fused power, +12V (leave this not connected when using new relay)
C: Ground ; connect this to new relay pin 85
D: Relay Trigger: Switched +12V, gets 12V when the ignition is turned ON and triggers the relay. connect this to new relay pin 86
E: needs constant +12V, should be getting power even when the vehicle is turned off. this feeds the Main computer, without power to this node, you'll get a P1600 Error even if using the bypass kit solution. not connected to new relay pins.
F: Requires +12V as a result of the relay being triggered. (this is the node where you apply direct battery power to see if the bypass solution will work or not) ; connect this to new relay pin 30

Also a on the ECM power Circuit diagram attached ( EFI master) , the EFI/ECD relay has nodes as 1,2,3,4. this is how to relate to our A,B,C,D nodes:
1 = F (+12V output)
3 = E (constant +12V)
4 = D (+12V switched / ignition)
2 = C (Ground)

Kindly update/edit if something is not correct.

 

[medtro]

Hi, I have read this thread front to back.
I have had similar issues to everyone here but mainly the EFI fuse melting (poor connection at B).View attachment 2006420
I pulled the relay and checked it - seemed ok - after reading this not so sure. But in checking everything out I have found that I now have no voltage at the switching terminal of the relay (D terminal in Medtro's diagram)
Beats me - where do I start??

Did you have the key turned to ON position? Either C or D (not both of them) should have voltage with key turn to set to ON. I don't have the car with me now so I can't verify which one.

 

[medtro]

So here's something to ease these diagram and wirings:

Going by the 2 terminals A and B of the fuse, and 4 terminals of the relay as per the attached diagram (fusebox1), this is what they correspond to:
A: Gets power once ignition is ON , +12V : connect this to new relay pin 87
B: Gets power when ignition is ON but gets fused power, +12V (leave this not connected when using new relay)
C: Ground ; connect this to new relay pin 85
D: Relay Trigger: Switched +12V, gets 12V when the ignition is turned ON and triggers the relay. connect this to new relay pin 86
E: needs constant +12V, should be getting power even when the vehicle is turned off. this feeds the Main computer, without power to this node, you'll get a P1600 Error even if using the bypass kit solution. not connected to new relay pins.
F: Requires +12V as a result of the relay being triggered. (this is the node where you apply direct battery power to see if the bypass solution will work or not) ; connect this to new relay pin 30

Also a on the ECM power Circuit diagram attached ( EFI master) , the EFI/ECD relay has nodes as 1,2,3,4. this is how to relate to our A,B,C,D nodes:
1 = F (+12V output)
3 = E (constant +12V)
4 = D (+12V switched / ignition)
2 = C (Ground)

Kindly update/edit if something is not correct.

View attachment 2006422

View attachment 2006428

My A & B are not switched by ignition key.

I also connected E to power pin on relay.

YMMV.

 

[850dualcab]

Pretty sure it was ON. Looking at the diagram i'll check the AM2 and IGN fuses tonight. Failing that i might have a dodgy wire perhaps

 

[BrittonJ85]

I have the same "crank but no start" issue. I've confirmed that I have spark from my new spark plugs and coils packs. I've also replaced the EFI fuse and relay.

I want to try this EFI trick but how do I know for sure that the EFI is the issue? What are other symptoms. When I pull the gas line off the fuel filter and crank the engine, fuel will spill out from the fuel filter.

Forward my video to 12:21 and see fuel come out the fuel filter.

 

[medtro]

If your security light blinks with your working key inserted, then you have this issue. I watched the video from your thread before and I believe you said engine light is ON with key ON. You probably don't have this problem if that is true. A quick test is to try to start the engine with 12V from battery connected to terminal F (see post #1).

I know you have fuel and new fuel pump. Perhaps the fuel pressure is not good. I have had 2 bad new fuel pumps in a row, I had to put in a 3rd fuel pump to correct the problem. You may want to check your coolant sensor too. There is a diagnostic section for no start problem in the FSM if you are not following that already.

 

[BrittonJ85]

If your security light blinks with your working key inserted, then you have this issue. I watched the video from your thread before and I believe you said engine light is ON with key ON. You probably don't have this problem if that is true. A quick test is to try to start the engine with 12V from battery connected to terminal F (see post #1).

I know you have fuel and new fuel pump. Perhaps the fuel pressure is not good. I have had 2 bad new fuel pumps in a row, I had to put in a 3rd fuel pump to correct the problem. You may want to check your coolant sensor too. There is a diagnostic section for no start problem in the FSM if you are not following that already.

Medtro, thanks for responding. After I insert the key, the key light goes off. Later this morning, I am going to try connecting terminal F to the battery positive terminal and see if she will fire up.

Thanks

 

[medtro]

Medtro, thanks for responding. After I insert the key, the key light goes off. Later this morning, I am going to try connecting terminal F to the battery positive terminal and see if she will fire up.

Thanks

It may fire up but it is definite a different issue.

 

[850dualcab]

So quick update. I had blown the ign fuse in the passenger kick pannel hence no swith wire 12v. Changed that and followed the wiring diagram advice and put in an aftermarket relay. WOW - it starts easier and doesnt stall after first starting when really cold (it use to). Also it had a little hesitation off idle and that is gone to! So I had been driving around with a poor connection across the EFi fuse for a while. Thanks so much for the information. Big thumbs up!

 

[BrittonJ85]

So quick update. I had blown the ign fuse in the passenger kick pannel hence no swith wire 12v. Changed that and followed the wiring diagram advice and put in an aftermarket relay. WOW - it starts easier and doesnt stall after first starting when really cold (it use to). Also it had a little hesitation off idle and that is gone to! So I had been driving around with a poor connection across the EFi fuse for a while. Thanks so much for the information. Big thumbs up!

I'm sorry to sound like "experienced", but does a 99 Land Cruiser have a passenger fuse kick panel? I ask because for the life of me, I cannot find it. I can only find the one on the driver side.

 

[semidriver]

This doesn’t work for me :/

 

[medtro]

This doesn’t work for me :/

What doesn't work? What is your symptom? What have you done? Please keep in mind this is not an universal fix for all no start problem. This fixes a unique no start problem. If you have the right symptom, this should fix the problem.

 

[semidriver]

What doesn't work? What is your symptom? What have you done? Please keep in mind this is not an universal fix for all no start problem. This fixes a unique no start problem. If you have the right symptom, this should fix the problem.

True I need to give more info.
I have one key that works great and starts the car, I have aftermarket key that I was able to cut and program to open and closed the door but I don’t know why i can’t program it to disable the immobilizer and start the car, so looking at this immobilizer bypass thread and did the relay thing. Everything stayed the same.

 

[medtro]

True I need to give more info.
I have one key that works great and starts the car, I have aftermarket key that I was able to cut and program to open and closed the door but I don’t know why i can’t program it to disable the immobilizer and start the car, so looking at this immobilizer bypass thread and did the relay thing. Everything stayed the same.

You are in the wrong thread. You need a different kind of bypass or fix your key. This bypass will NOT start your engine with your aftermarket key.

 

[medtro]

I'm sorry to sound like "experienced", but does a 99 Land Cruiser have a passenger fuse kick panel? I ask because for the life of me, I cannot find it. I can only find the one on the driver side.

May be it depends on which side is the passenger side. I am guessing it could be on the passenger side for this vehicle.

Picture from post #12,413

 

[JLT]

Male Terminal E fused straight from + battery using oem relay. All else wired the same. Works flawlessly now.

 

[Rolocado]

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

I just tried to jump Terminal D to the battery and sparks flew... any reason for that? Using a 14 AWG wire and a space connector....

 

[medtro]

I just tried to jump Terminal D to the battery and sparks flew... any reason for that? Using a 14 AWG wire and a space connector....

It is either ground or 12V but I don't remember which one. I am going to guess it is ground since you got sparks. What is the reason for jumping Terminal D to the battery?