Ls 400 Starter Replacement Gone Bad

[StanTheMan]

I have spent the last couple of days replacing the starter on my 2000 LS 400. This is a very difficult job, you have to pull the intake manifold to get to the starter. Everything on the replacement went fine except, when I turn the key the car won't start. Replaced another starter, same result. Is there a computer problem that is preventing the car from starting. Any help or suggestions would be greatly appreciated. The engine will not turn even while torn apart, I can hear the starter relay working, no click on the starter, nothing!

[qha_vn]

most likely you have electric connection issue. to narrowdown the causes i suggest

- test the starter motor by connecting it directly to battery. if it runs well, proceed next step

- check the ECU power source circuit

have a question: which leads you to replacing the starter?

[StanTheMan]

I replaced the starter because it would click and not start the car. We would have to rock the car and retry starting the car, it behaved very similar to a bad solenoid. I did check voltage between the positive connection on the starter and the ground on the battery and voltage was present. I have checked all of the fuses, the starter relay clicks which makes me think the starter switch is working. I talked to Lexus and he stated that he did not think there was any computer fail safe that would prevent the starter from cranking. Plan on taking off the intake tonight and try the suggestion above connecting the starter directly. Any help from any techs or someone with experience would greatly appreciated.

[landar]

Hey Stan. You say you checked the voltage between the starter and ground but did you test the voltage

while you were trying to crank it? Bet it drops to near zero.

When I replace a starter, I always bench test the starter motor before installing. By that I mean I use jumper cables

to actually supply juice to the motor and then engage the solenoid by(very breifly!) touching +12v to the solenoid terminal. I clamp the

motor down because it will torque and jump. You have to be careful but its not rocket science.

If the starter checks out, then its time to look elsewhere.

I am playing couch potato quarterback on this one but it sounds like maybe your solenoid wire is OK while the much heavier

gauge wire to the starter motor itself is somehow defective/high resistance. The starter pulls lots of current(> 100A) so good, clean connections are paramount. You should also check for a poor ground connection. Remember that any bad connection whether at

the battery, in the wire or at the starter, +12v or ground, will render the whole thing kaputski.

[StanTheMan]

I have voltage to the starter main terminal, I also have a good ground, I do not have any voltage that is going to the trigger wire at the solenoid when the key is turned in the ignition switch. I do have a click in the relay, could this be either the park nuetral switch or the ignition switch.

[landar]

I have voltage to the starter main terminal, I also have a good ground, I do not have any voltage that is going to the trigger wire at the solenoid when the key is turned in the ignition switch. I do have a click in the relay, could this be either the park nuetral switch or the ignition switch.

Hmmm, now you have piqued my interest. I have to plead ignorance on not knowing if a 2000 LS has a relay between the ignition switch and the starter solenoid.

If so, it may be your relay contacts have gone bad. The fact that you dont have any voltage to your 'trigger' wire is the main issue. The focus should now be

on what drives the trigger wire. Relay or ignition switch? I will do a little digging for a schematic and let you know.

[landar]

Ok, it seems there is a relay which drives the solenoid. I would check out this relay and see if

it might be defective. If it checks out fine, look into the theft deterent system. Maybe +12v is not

being supplied to the contacts on the relay.

st_18.pdf

[Harky]

The wiring diagram for my '96 shows a 40A fuse in JB2 for the starter relay and a 7.5A fuse in JB1 (labeled "STARTER") for the park and neutral switch inputs to the ECU. I don't know if this matches the wiring on your 00 but it might be close. Have you checked ALL of your fuses ??

[westcoastsooner]

The wiring diagram for my '96 shows a 40A fuse in JB2 for the starter relay and a 7.5A fuse in JB1 (labeled "STARTER") for the park and neutral switch inputs to the ECU. I don't know if this matches the wiring on your 00 but it might be close. Have you checked ALL of your fuses ??

I believe my starter is going out on my Ls 400.Would it be best to take it to a Lexus Mechanic?I got a quote $960.00,....Good bad? I just dont know....

[StanTheMan]

I have been trying to reply each and every day for almost a week, this Forum kept on returning an error code and sending error messages to window every time I tried to make a reply. I even replaced my computer registry with an earlier version, sorry about the wait.

It turned out to be a bad connection on the wiring harness behind the intake manifold. In reply to WestCoastSooner, I would take the car in for that price. I have done a lot of work on vehicles of all makes and models including converting auto transmission to manual and complete engine rebuilds. I have found Lexus a pain in the rump to work on. The fuel injectors are very sensitive, tiny little O rings the Toyota dealer nearest to me wanted $4.65 a piece times eight. Napa had complete injector kits to $1.99 each that incluced the four seals per injector necessary to reinstall the fuel rail. Thank God this job is done and I want to thank everyone that put up a post that !Removed! isted me in completing this job. I also replaced the timing belt and changed spark plugs, the car has 103K miles.