My immobilizer fix (4 Viewers)

[Greenbean]

Are you sure you have this problem? Does your security light blink when you try to start the car?

My 2000 LC died on me today while driving. Tried four or more times and it finally fired back to life.

I made it back home,

I never saw the immobilizer light though.

Does that mean this kit won’t help?

 

[medtro]

My 2000 LC died on me today while driving. Tried four or more times and it finally fired back to life.

I made it back home,

I never saw the immobilizer light though.

Does that mean this kit won’t help?

Correct, if your security light didn't blink while cranking then you have a different problem.

 

[kevin2i]

Did the F to battery to get it going (after a few years of jiggling the fuse).
Instead of installing a new relay, I used the existing fuse box, but bypassed the fused current>relay. I inserted a jumper from “B” to “E”. This just takes the (fused) current directly to the relay.

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.

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 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

 

[lexs470]

Did anyone resolve the P1600 error after utilizing the kit ? Thanks.

 

[lexs470]

Did the F to battery to get it going (after a few years of jiggling the fuse).
Instead of installing a new relay, I used the existing fuse box, but bypassed the fused current>relay. I inserted a jumper from “B” to “E”. This just takes the (fused) current directly to the relay.

View attachment 1980858

Hi Kevin, I have a question, my fused locaiton B as per the diagram attached is not getting any current neither is location A. so i completely needed to bypass my fuse holder location for the EFI fuse.
Do you by any chance have the schematic/diagram for the EFI fuse that you can share. I'm guessing terminal F is the output 12V, terminal E where you got the power to is where the input of 12V is for the relay. that leaves terminals C and D, and I'd like to know what those two terminals are for. thanks in advance.

 

[lexs470]

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

Hi Medro,
have a question, because using this solution is is giving me a P1600 error code I'm trying to trouble shoot it.
Do you have the factory wiring diagram for the EFI relay which I'm guessing you used to figure out what the 4 terminals C,D,E, and F are to connect to with your kit.
Also, for Location A and B of the fuse, is A supposed to get the power input to the fuse and B is the ouput of the fuse ?
thanks much.

 

[lexs470]

posting a picture of how power should be applied to factory relay. based upon the kit by medtro,

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

your kit terminal E left out of your kit, as per the ECM diagram I'm attaching that needs a constant battery power which if it's not there is likely throwing the P1600 code for some. I still have to test that out.... but I wanted to discuss with you before I went any further. thanks again for your invaluable help here .

 

[lexs470]

I ended up rigging the same bypass but using the original relay. Worked like a charm. I was doing something and heard/felt the relay click and realized that the 11.5v was enough. I then rigged an inline fuse (same fuse type as the box) and put it all together and its working great. Thank you very much for the help and working through my confusion.

DrJMan, did you leave the terminal E blank ? if so did you ever get the P1600 code by leaving it blank or did you feed it power ? thanks.

 

[lexs470]

FYI. I ran power directly from the battery to that side of the fuse and the car starts fine but, you get a CEL ECM fault code.

I cleared it a few times and it came back right away. I put the fuse back in and the relay and the code went away.

I think the ECM powers that pole somehow and it doesn't like when it gets power directly from the battery.

I am going to disassemble the fuse box and get to that post inside and run an external fuse there.

In my case at least part of the issue is the female of the fuse holder not making good contact because it is unsupported somehow.

Hi Bob,
did you ever figure out the error you used to get when you were powering the bypass kit straight from the battery ? i'm getting the same error and like you said, the error goes away when i put the original relay back in. interesting thing is that i don't put in the EFI fuse back in, just the original relay without any EFI fuse and the CEL still goes away... stuck on this one...

 

[lexs470]

adding another diagram, showing that the BATT terminal of the ECM requires 12V as well. given in the bypass harness we are leaving terminal E blank, that leaves BATT of ECU needing the 12V that it doesn't hence throwing a P1600 code for me and a few others.
Waiting for someone who used the bypass kit, got the error code and fixed it so I can confirm my hypothesis. thanks and hoping this would help others as well.

 

[medtro]

Did the F to battery to get it going (after a few years of jiggling the fuse).
Instead of installing a new relay, I used the existing fuse box, but bypassed the fused current>relay. I inserted a jumper from “B” to “E”. This just takes the (fused) current directly to the relay.

View attachment 1980858

I don't think you bypassed anything but your jumper helps providing 12V to the relay.

 

[medtro]

Did anyone resolve the P1600 error after utilizing the kit ? Thanks.

See post #70.

 

[medtro]

Hi Medro,
have a question, because using this solution is is giving me a P1600 error code I'm trying to trouble shoot it.
Do you have the factory wiring diagram for the EFI relay which I'm guessing you used to figure out what the 4 terminals C,D,E, and F are to connect to with your kit.
Also, for Location A and B of the fuse, is A supposed to get the power input to the fuse and B is the ouput of the fuse ?
thanks much.

Yes and yes.

 

[medtro]

posting a picture of how power should be applied to factory relay. based upon the kit by medtro,



your kit terminal E left out of your kit, as per the ECM diagram I'm attaching that needs a constant battery power which if it's not there is likely throwing the P1600 code for some. I still have to test that out.... but I wanted to discuss with you before I went any further. thanks again for your invaluable help here .

View attachment 1981323

That should take care of the problem. My current kit has this covered.

 

[medtro]

adding another diagram, showing that the BATT terminal of the ECM requires 12V as well. given in the bypass harness we are leaving terminal E blank, that leaves BATT of ECU needing the 12V that it doesn't hence throwing a P1600 code for me and a few others.
Waiting for someone who used the bypass kit, got the error code and fixed it so I can confirm my hypothesis. thanks and hoping this would help others as well.

View attachment 1981409

Wrong diagram for the year.

 

[lexs470]

Wrong diagram for the year.

Thanks,
thanks.
as for the P1600 code, someone mentioned that you sent them an update wire etc to fix it. i'm guessing based upon the link you posted for the error code that somehow you have supplied node E which is left blank with a constant 12v source ? if so , where did you tap into for the constant 12v source to feed the left out node E.
I'm surprised not everyone using the kit ended up with the P1600 code given E is not used and that's what sourcing the BATT point on the ECM which if not present throws the error code. ?

 

[lexs470]

That should take care of the problem. My current kit has this covered.

thanks much, what is a good place to tap into the constant 12V, what about the to your kit that's feeding the relay, can we simply tap into the same source and feed terminal E.
In essense, I assume what we are doing is shorting terminals B and E with a fuse in between, or getting a constant feed of 12V from the battery to terminal E with a fuse in between ?
thanks again much appreciate this.

 

[lexs470]

P1600 TOYOTA ECM BATT Malfunction

thanks, perhaps for the clarification of others who read this thread, is it correct to point out that the E terminal where the original relay was connected and is left out in the pictures here for the solution (ofcourse corrected in your updated kit); E terminal is connected to the BATT node of ECM which requires a constant 12V power. and this error will be resolved by not leaving it emply but by feeding it constant 12V fused power source ?

 

[medtro]

Thanks,
thanks.
as for the P1600 code, someone mentioned that you sent them an update wire etc to fix it. i'm guessing based upon the link you posted for the error code that somehow you have supplied node E which is left blank with a constant 12v source ? if so , where did you tap into for the constant 12v source to feed the left out node E.
I'm surprised not everyone using the kit ended up with the P1600 code given E is not used and that's what sourcing the BATT point on the ECM which if not present throws the error code. ?

thanks much, what is a good place to tap into the constant 12V, what about the to your kit that's feeding the relay, can we simply tap into the same source and feed terminal E.
In essense, I assume what we are doing is shorting terminals B and E with a fuse in between, or getting a constant feed of 12V from the battery to terminal E with a fuse in between ?
thanks again much appreciate this.

Do you really need to have multiple posts to ask the same questions?

Not everyone ended up with P1600 even E is not connected to anything. Not all my kits have E left unconnected either. I have one owner reported with P1600 so far, and it is resolved with 12V supply to E.

I use the fuse holder to power terminal E.

 

[lexs470]

Do you really need to have multiple posts to ask the same questions?

Not everyone ended up with P1600 even E is not connected to anything. Not all my kits have E left unconnected either. I have one owner reported with P1600 so far, and it is resolved with 12V supply to E.

I use the fuse holder to power terminal E.

I figured I'd someone else stumbles upon other posts they would get the solution too. Thanks again. You're awesome !