'99 no start (but cranks) after battery replacement - stumped. (1 Viewer)

[FieldGypsy]

Hey everyone - I have searched the forums while on my phone (currently in a parking lot with a no start rig) - I have tried multiple resolutions that I will list below.
ISSUE - No start, but fast crank. I JUST replaced the battery in a parking lot. I drove to the parking lot, no issues. Went to start, and it gave the classic "click" sound of a low/bad battery. New battery, cleaned cables, go to start and just spins the motor. Dang.

DETAILS OF POSSIBLE FIXES -
I have checked the EFI fuse under the hood. Replaced with a 30. Also tried a new 20. Fuse box looks very clean (2nd owner, 120k miles, garage kept and never off road until me). Nothing changed.
I ran across some (actually a lot) of the forums about running a jumper from the EFI relay to the battery. Tried that with some 14g wire running directly to the positive post. Still nothing. I also tried to jump the EFI fuse. I am confident that I ran the jumper correctly after 3+ people that stopped to check I also had check to make sure I am not an idiot.
Is there another fuse that I may have been missing under the passenger side kick panel? Maybe a fuel pump fuse or something?

Currently, I only have my aftermarket key that I programed to the ECU after a chip swap and I have had 0 issues in the last year with this. Now, when I crank it over, the "immobilizer" light on the dash blinks, hence why I tried the jumper (with no luck). The local auto store can get a new relay, but not till next friday.

Does anyone have any ideas? I highly doubt the ECU just "forgot" my key during a battery swap, considering I drove there with 0 issues. I believe that I am going to have to get a hotel for the night and see if I can tackle this the next day. The key that I have still has an active battery (meaning when I press the unlock/lock button the red light still turns on). I never programmed it to remote lock/unlock the doors.

I will constantly be checking this if anyone has anything I should check! I have limited tools, but always looking for an excuse to buy more I guess.

 

[awesomeissquid]

So with the key when you put it into the ignition but don’t turn it what does the security light do? I think if it either goes out immediately or stays solid for a second and then goes out the key is still registered to the ECU. Not sure if it keeps blinking if that means the key was forgotten somehow.

@Mauser might have an idea.

 

[RND1]

Sounds like an immobilizer issue. Basically, you have to bypass the bad EFI relay circuit in the fuse box so that the immobilizer system gets adequate power supply to start the 100. Here's a couple of threads detailing the issue and fix.

My immobilizer fix

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...

forum.ih8mud.com

EFI Relay Bypass Kit (Immobilizer Fix) for UZJ100/LX470

This bypass kit bypasses the bad EFI relay circuit in the fuse box so that the immobilizer system gets adequate power supply for starting the car. I made this for myself after my new 30A replacement fuse - initial fix for crank but not start problem, failed to start after 4 days. Some members...

forum.ih8mud.com

 

[medtro]

Now, when I crank it over, the "immobilizer" light on the dash blinks, hence why I tried the jumper (with no luck).

Not sure how you jumped it but please give this a try.

 

[FieldGypsy]

Not sure how you jumped it but please give this a try.

Hi Medtro -

I ran the jumper with a blade connector in the "F" slot like you have diagramed, and then ran it directly to the positive end of the battery (ran the wire around the bolt post then tightened it down) - no luck. I also ran a jumper at the EFI fuse (like others have mentioned) with no luck.

I did see a picture wayyyyy down in one of the forums that they put the jumper in the "F" slot - and then replaced the relay with the wire in. It seems like that may stretch some connections out but I may give that a shot if you agree (or disagree). I do not see how they would actually help - but I need to get the rig down the road.

I am still leaning toward the immobilizer issue - Now that it has warmed up above 20 degrees, I am going to try and make another jumper to double check that I did not miss something.

 

[Mauser]

I am wondering if one of the legs of the immo eeprom isn't making contact.

 

[FieldGypsy]

I am wondering if one of the legs of the immo eeprom isn't making contact.

That was one of my thoughts as well - but its a strange gremlin if this happened to occur immediately after a battery replacement. Luckily I have some experience pulling that with your help last time! I may pull it and visually inspect it before I try and get a ride to pick up a heatgun/soulder.

 

[medtro]

I did see a picture wayyyyy down in one of the forums that they put the jumper in the "F" slot - and then replaced the relay with the wire in. It seems like that may stretch some connections out but I may give that a shot if you agree (or disagree). I do not see how they would actually help - but I need to get the rig down the road.

I agree, I don't see how that would help. Try bending the blade connector slightly for better connection to see if that helps.

 

[FieldGypsy]

Update for everyone -

I pulled the computer to check the chip connection for the eeprom. They look good.

I tried all the jumpers, different blades, different wires, different brand new fuses and nothing

 

[FieldGypsy]

Update for everyone -

I pulled the computer to check the chip connection for the eeprom. They look good. But maybe I should re solder.

Sat in the car with the radio on for 15 minutes per another random lucky thread fix.

I tried all the jumpers, different blades, different wires, different brand new fuses and nothing.

I think I have one more option, but I don't know if it's worth it - have someone bring me the other keys (4 hour drive one way)....

I'm open to any other suggestions or comments to how I maybe can get out of this pickle.

 

[KliersLC]

This sounds like a fusible link issue from the 80 series forum, but I'm not even sure if the 100 has the fusible link, or if what you already tried would have bypassed the fusible link.

Aside from that, it could be a unlikely, but possible coincidence in that the fuel pump failed at the same time you changed your battery. Can you verify fuel pump operation and also check for spark?

 

[RND1]

Long shot, but did you already look at the neutral safety switch?

 

[FieldGypsy]

Long shot, but did you already look at the neutral safety switch?

Oh good call. I'll look into that today. Going to look at it today for that.

 

[2001LC]

Cranking on start:

1. Immobilizer, Okay (light not blinking with key in). Next:
2. Neutral SW. Put in N and start. Still No start. Move to next step.
3. Disconnect fuel line at fuel pump (squeeze green clip and pull line off.) Run a line from fuel filter to catch can. Crank engine, and fuel will fill catch can while cranking. No fuel pumps out to catch can. Fuel starvation. Likely bad fuel pump. But can be frozen water in fuel system. Other issue can reduce or stop fuel flow also.

Note fuel is highly flambe. Any spark can ignite its vapors. So great can must be taken. If fuel is flowing in system and building pressure. When line disconnected from fuel filter, it will spray in uncontrolled direction. Using a rage around fitting as line pulled off, can help control spray. If vehicle sits without cranking or engine running for 8 hours, pressure tends to be lower (~ 5 to 20PSI) in fuel system. If just cranked engine or ran engine. Presume should be high (~38PSI) in system.

 

[Cosmo Kramer]

you say "Neutral SW. Put in N and start. No start. " --- does this mean it started then died?

 

[FieldGypsy]

I am wondering if one of the legs of the immo eeprom isn't making contact.

Mauser and everyone - I have some good news...I guess....and some bad news.
I got the rig towed back to my shop and finally got my code reader on it.
Here are the codes - which I am going to look into more, but wanted to keep others on here (and those that have PMed me with issues similar) updated.

Codes - B2795 -"Unmatched Key Code (Immobilizer system)
B2796 - "No communication in Immobilizer system"

 

[FieldGypsy]

Mauser and everyone - I have some good news...I guess....and some bad news.
I got the rig towed back to my shop and finally got my code reader on it.
Here are the codes - which I am going to look into more, but wanted to keep others on here (and those that have PMed me with issues similar) updated.

Codes - B2795 -"Unmatched Key Code (Immobilizer system)
B2796 - "No communication in Immobilizer system"

Also - I looked at the eeprom very well and it seems to be still in there - but I may have to pull that if I can not find anything else.

 

[2001LC]

you say "Neutral SW. Put in N and start. No start. " --- does this mean it started then died?

No. Sorry I was in a hurry, laying out a diagnostic tree. It means if does NOT start once shifted to N and cranked, then "likely not" neutral SW issue.
Move on to fuel pump testing.

 

[Mauser]

Mauser and everyone - I have some good news...I guess....and some bad news.
I got the rig towed back to my shop and finally got my code reader on it.
Here are the codes - which I am going to look into more, but wanted to keep others on here (and those that have PMed me with issues similar) updated.

Codes - B2795 -"Unmatched Key Code (Immobilizer system)
B2796 - "No communication in Immobilizer system"

Well shoot. I wonder if the antenna could be bad and the chip in the key isn't being read.

Let me know what I can do to help.

 

[FieldGypsy]

Well shoot. I wonder if the antenna could be bad and the chip in the key isn't being read.

Let me know what I can do to help.

Mauser (or anyone that may have a similar problem) -

I am wondering if someone tried to put a key in their LC that does not have the proper RFID signature for the ECU, do they get the same two codes? For me to get those two codes during code reading, I have plugged in the code reader and turned the ignition to "ON" but obviously not running. I doubt anyone has a key that is cut, but not programmed laying around...but if so that may help quite a bit.

I figure the EFI relay is good since when I replaced the jumper the rig did not start. I figure the main fuse box is good since I have replaced the fuses with NEW ones. I have also looked for any sign of melting or non-contact with none observed.

My next (hopefully logical) steps:
1 - I am looking into the immobilizer system that is within the ignition now, I will try and pull that tonight and see if that has continuity.
2 - (advice needed on this one) - I have seen other toyotas have success by "jumping" two specific ports on the OBD2 port (ports 4 and 13), and then leaving the vehicle to "on" for 20+ minutes for a "handshake". I doubt that will work for ours since I have not seen that on the mud forums. Seems easy though. Picture attached below.
3 - call toyota and beg for a new ECU like some have reported if I purchase two "master keys". I do not know if anyone has had recent success with this, and I am doubtful with the chip issues (and the rig is now 20+ years old)
4 - remove the ecu and send it to someone to reprogram the ECU or replace the EEPROM.
5 - Pull the whole fuse box and look for issues on the bottom side that may have non-contact.

Any advise on maybe skipping a step or starting with another one is welcome while I try and chase this down. No matter what, when I find the solution I will post it and let future mudders know.
3 -