elite7

Has anybody had experience with diagnosing No crank No start?

My 2002 Sc430 wont crank and wont start. I replaced Starter, Ignition Switch, and Starter relay.

Still no crank. I'm thinking to try Neutral Safety Switch has anyone ever done that fix?

Poqman

Does your battery have at least 12.4 VDC? Low battery will not try and start.

elite7

Yes battery is supplying proper volts. With a test light on Drivers side engine fuse box im not getting power to fuse 63 starter, 64 efi no 2, 65 ign, 66 inj.

Starter relay clicks when you try to start but no crank and no start. A week before this happened i would have to hold key all the way to the right for 2-3 seconds and then the car would start to crank and fire up.

Chaditotx

iTrader: (1)

Voltage can be misleading. I'd suspect a battery with a few bad cells in it. If you don't have amperage, you won't be able to turn motor over, and possibly not have enough "juice" to get relays to engage. Just my 2 cents.

Htony

Sounds like the car is in lock up mode? Shot gunning the problem can waste time. Use analog multimeter, digital ones can mislead you due to it's high input impedance.

GmanSC

First try with the new battery then try to start in Newtral position.

elite7

Thanks for suggestions. I will try new battery see if it works.

elite7

Tried new battery no luck. Any ideas?

With a test light on Drivers side engine fuse box im not getting power to fuse 63 starter, 64 efi no 2, 65 ign, 66 inj.

What connects to these fuses? I dont have a wiring diagram.

Harold57

The fact that the starter fuse is not getting power but the starter relay clicks when you turn the key are conflicting pieces of information. The starter wouldn't make any noise if there were no power going to it.

A WAG would be that the ignition key switch has dirty contacts, which may explain the 2 to 3 seconds for it to start in the past, or maybe something is awry with the immobilizer. But without being there and poking around myself, I couldn't say for sure and even then, I'm not sure that I would be able to track it down since I'm not as intimate with the total design of the electronics of this car.

Htony

MY wild guess is there may be more than one fuse link. If that is the case, one is blown? Is the radio working? Are all the lights working. Have multi meter?

elite7

I put a new ignition switch in still no crank. Starter doesnt make any noise the relay only clicks when you turn the key. The starter cranks if i jumper wire it and wont start but no crank at all from turning the key.
Radio works and lights work fine. I have a multi meter but not experienced with using one.

JohnnyCake

Here's something I just learned that might be helpful in determining whether the ignition switch or the park/neutral safety switch is part of the problem.

If the park/neutral safety switch is not enabled, then upon turning the key, the lights on the NAV and climate control will go off (NAV power cycles), BUT the dash lights stay on.

If the park/neutral switch is engaged (i.e. you are in park/neutral and the car knows that), turning the key will cause the dash lights and the NAV and the climate control to go dark during the key turn process.

I think this helps diagnose as follows.

Turn key:
1. If no change in any lights (dash/NAV/Climate) = ignition switch itself is bad.
2. If NAV/Climate lights go out, but dash light stays on = park/neutral safety switch is not engaged (i.e. car does not think it is in park/neutral) but ignition switch is good
3. All lights go out, still no crank = something farther down the line, but safety switch and ignition switch are good

Check out this thread to diagnose between starter/solenoid:

https://www.clublexus.com/forums/sc4...problem-2.html

elite7

I changed ignition switch. When i turn the key the climate lcd goes dark and when i release key it lights up again.

Htony

That little click is from a small relay which enables chunky solenoid/contactor on the starter motor which draws very high current. That little clicking relay contacts are bad?
I'd lso double check wiring going to the starter.

elite7

Thanks for advice relay is brand new so its good. I jumpered the starter and its cranking but only if i jump it so the wiring is fine. Its not cranking when i turn the key. Starter is brand new and i double checked wiring twice.