97 Crank and No Start

[MisipLC]

I have a 1997 LX450. It began with a crank no start. Took the truck Toyota and they replaced the relay in kid panel on the driver side. The truck crank and ran. I brought it home and the truck continued to crank approximately for several days. Then it would not crank. I research and read "crank no start" threads and replaced the electric fuel pump relay in the engine compartment. The truck again cranked and ran. I ran the truck for several days. Yesterday I drove the truck and then parked it. Tried to restart and could only get crank, no start. This morning I tried the truck again, and it started. I did not drive the truck. This afternoon I again tried the truck, and it would not start. The check engine light does not come on. It did light up when the truck did crank and run.
All this has occured over the past 4 weeks.

The fusible link appears to be in good shape.

I am at the point of needing help on what to do next. Any help would be greatly appreciated. Thanks.

 

[Fj80oregon]

I have a 1997 LX450. It began with a crank no start. Took the truck Toyota and they replaced the relay in kid panel on the driver side. The truck crank and ran. I brought it home and the truck continued to crank approximately for several days. Then it would not crank. I research and read "crank no start" threads and replaced the electric fuel pump relay in the engine compartment. The truck again cranked and ran. I ran the truck for several days. Yesterday I drove the truck and then parked it. Tried to restart and could only get crank, no start. This morning I tried the truck again, and it started. I did not drive the truck. This afternoon I again tried the truck, and it would not start. The check engine light does not come on. It did light up when the truck did crank and run.
All this has occured over the past 4 weeks.

The fusible link appears to be in good shape.

I am at the point of needing help on what to do next. Any help would be greatly appreciated. Thanks.

Fusible links are cheep and a easy parts cannon swap. Appears good doesn’t mean it is in good shape. I would inspect further. This sounds like a intermittent issue and for under 20$ is a no brained. Buy two so you have a extra. Also check wiring next to egr pipe.

 

[60 toy ota]

Failing that, next time key is on with no cel take that opportunity to jiggle key locations in your wiring to narrow down the fault (fusible link, fire wall grommet, etc)

 

[gummycarbs]

Any alarm or immobilizer? Did the LX450 come with any kind of immobilizer, or did it just have the fancy inverted/internal cut key?

 

[MisipLC]

Thanks guys for the excellent response. I’ll order fuse link and try wire jiggle thingy.

 

[MisipLC]

I will check for alarm. Where would you suggest in looking next to EGR pipe?

 

[MisipLC]

Any alarm or immobilizer? Did the LX450 come with any kind of immobilizer, or did it just have the fancy inverted/internal cut key?

It has the backwards cut key that you have to find a special guy to cut the key.

 

[manofthewoods]

It has the backwards cut key that you have to find a special guy to cut the key.

My local Lexus parts guy got me a key in no time.
Not exactly cheap.

 

[Jeeper]

The ECU is not getting power if the CEL does not illuminate at key on. @jonheld is the pro/master/king on this. Search his name and your keywords for lots of help.

You need to first see if you have 12v at the B+ terminal on the diagnostic connector on passenger firewall w key on. That will direct your next steps.

 

[MisipLC]

The ECU is not getting power if the CEL does not illuminate at key on. @jonheld is the pro/master/king on this. Search his name and your keywords for lots of help.

You need to first see if you have 12v at the B+ terminal on the diagnostic connector on passenger firewall w key on. That will direct your next steps.

Thank you Jeeper. I’ll get my meter and check the connector for 12v and report back.

 

[MisipLC]

My local Lexus parts guy got me a key in no time.
Not exactly cheap.

Yes my son learned this painful lesson when he lost his key while in the desert at NTC with Miss Army Guard.

 

[Malleus]

I'd bet there's a load of loot in the sand at the NTC.

@Fj80oregon is referring to the engine wiring harness that rests (or very nearly rests) on the EGR pipe at the rear of the head. It's very common for the EGR pipe to burn through the wiring insulation and you get an unwanted ground in the harness. I do not think this is your problem.

No CEL (the engine icon light) means the ECU isn't getting power. The ECU power on starting is initially through the fusible links at the battery. That's the first point of failure, assuming your battery is good.

Then power goes to one of three fusible links.
The FL AM1 and AM2 power the ignition circuit.
The FL MAIN2 powers the ECU circuit: the ECU fuse (15A EFI) in the engine compartment fuse block and then to the ECU.
You need all three links in order to start the engine.

You can test the links to make certain they have continuity. A cheap meter or light will work, but a good meter will also give the the resistance values, which are good to know for predicting failure. When the wire degrades (corrodes, breaks, etc - remember these are stranded wires so each and every strand counts) the resistance increases until finally there isn't enough wire to handle the heat load from the current and it melts. That's why the different wire thicknesses in the harnesses - each carries a different current and thus has to be able to reject a different amount of heat.

Here's the diagram:

I attached the entire section. This is from my 1995 EWD, but yours is the same. I don't have a copy of the 1997 LX450 EWD; you'll need one for further investigation.

You should download a copy of the EWD for your model; they should be in the Resources section. LMK if you can't find the one for your model and I'll try to locate for you.

 

[MisipLC]

Here is an update.
Check for 12V at Ignition fuse - Left leg 12V found.
Pulled 22pin plug on ECU and tested Pin 1 and 12. Used door catch inside door frame as ground. Found 0v. Couple of times read .5v.
I have ordered a fusible link.
Electric fuel pump relay has been replaced.
Relay in driver side kick panel has been replaced.

Check the left leg of 15A fuse for EFP. Found 12.4V.

Found truck does have a security system installed.

Truck still crank/no start.

 

[Jeeper]

Do you have 12v at the B+ terminal of the diagnostic connector?

 

[inkpot]

This is the wiring connection that failed for me. Right below the reservoir.

 

[MisipLC]

I'd bet there's a load of loot in the sand at the NTC.

@Fj80oregon is referring to the engine wiring harness that rests (or very nearly rests) on the EGR pipe at the rear of the head. It's very common for the EGR pipe to burn through the wiring insulation and you get an unwanted ground in the harness. I do not think this is your problem.

No CEL (the engine icon light) means the ECU isn't getting power. The ECU power on starting is initially through the fusible links at the battery. That's the first point of failure, assuming your battery is good.

Then power goes to one of three fusible links.
The FL AM1 and AM2 power the ignition circuit.
The FL MAIN2 powers the ECU circuit: the ECU fuse (15A EFI) in the engine compartment fuse block and then to the ECU.
You need all three links in order to start the engine.

You can test the links to make certain they have continuity. A cheap meter or light will work, but a good meter will also give the the resistance values, which are good to know for predicting failure. When the wire degrades (corrodes, breaks, etc - remember these are stranded wires so each and every strand counts) the resistance increases until finally there isn't enough wire to handle the heat load from the current and it melts. That's why the different wire thicknesses in the harnesses - each carries a different current and thus has to be able to reject a different amount of heat.

Here's the diagram:
View attachment 3191740


I attached the entire section. This is from my 1995 EWD, but yours is the same. I don't have a copy of the 1997 LX450 EWD; you'll need one for further investigation.

You should download a copy of the EWD for your model; they should be in the Resources section. LMK if you can't find the one for your model and I'll try to locate for you.

Malleus, thank you for this. I did find LX450 EWD in resources.

 

[MisipLC]

This is the wiring connection that failed for me. Right below the reservoir.

View attachment 3191786

I will check that. What exactly did you find?

 

[Jeeper]

I think you are stating above that the plug to the ECU doesn't have 12V with key ON, is that correct? If so, check the B+ terminal at diagnostic connector to start working back to the battery. This will help determine if the issue is between the diagnostic connector and the ECU (my issue)- or the diagnostic connector and the battery (@inkpot issue). Many folks have had many issues. Narrow down the location to help steer your efforts.

 

[inkpot]

I will check that. What exactly did you find?

The wire had corroded away from the pin in the socket. I hard wired it first, but several years later I replaced my entire engine harness, so I reassembled it all with the appropriate pins and sockets.

 

[MisipLC]

This is the wiring connection that failed for me. Right below the reservoir.

View attachment 3191786

Does that wire power the ECU? Is it tied into the diagnostic, B+ on the passenger side firewall?