2002 LS430 161K all of a sudden wont start. Suspected the Battery got new Battery problem still exists. When turning key I get 1 slight click and doesn't crank at all. When I hooked up a scan tool it read no codes but when turning key it makes reaping clicking sounds coming from under the intake where the starter is located. If I unplug the scan tool it doesn't make the clicking at all just a slight click and nothing happens except VSC off check VSC. I don't believe the VSC is malfunctioning because no codes are stored. Any ideas????
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Same as any car, check your ignition switch, starter relay, crankshaft position sensor, camshaft position sensor, left and right VVT sensors, and the starter itself.
Fuel pump relay and fuel pump problems may cause this, but I think the crank or cam position sensors are more likely to be suspect. There are DTCs for those sensors, but I'm not sure if those DTCs can be set that quickly while attempting to start the car.
Generic (non-Toyota/Lexus) scantools determine which protocol the car uses by first attempting to handshake with the car via the OBD2 pins that Toyota/Lexus uses for the VSC system. A signal on those VSC pins disables the Toyota/Lexus VSC system. In other cars, these pins are used for data communication signals.
I suspect that your scantool is disabling the VSC system, which may bypass one or more sensors that stop your starter from engaging to begin with. Generic scantools may not read extended codes that relate to the VVT sensors.
Think like a dealership/mechanic.. run through the usual diagnostic steps for a car that won't start, from least effort to most effort.
Given your symptoms (clicking but no cranking), I would recommend some easy tests first.
If you don't have a Digital MultiMeter (DMM), buy an inexpensive one. Harbor Freight has them for under $10.
Any model will do for automotive use; it doesn't matter much what features it has because you only need the 20VDC range and a continuity (Ohms) range, preferably with an audible beeper to indicate low resistance.
It will come in handy many times in its life, maybe even just to check flashlight batteries.
First, check the battery voltage directly at the terminals (lead cylinders INSIDE the clamps, which are part of the battery itself). Even a brand new battery could be defective or discharged, and this test takes only about 2 minutes, including opening the hood :-)
The voltage should be at least 12.6 or perhaps a bit more if the car has recently been run or the battery has just been charged.
Second, measure the voltage again, but with the probe tips stuck into the clamps themselves. the voltage should be exactly the same. If even .01V lower, the clamps probably need to be tightened. They may need to be tightened even if the voltage is identical.
Third, there is a joint in the positive battery lead that very commonly gets corroded. It is inside the cable about 2 to 3" from the clamp, so is not readily visible. Replace the positive clamp if it has any corrosion. The negative clamp seems to have fewer problems, but it would be good to check it also.
Fourth, use an alligator clip to attach the negative probe to a good ground or the negative battery terminal.
Then put the positive probe tip on various points along the cable from the battery to the large stud on the starter motor solenoid. Check the voltage with the key in the START position. An assistant would be helpful here, as would a diagram of the starter circuit.
At this point, you will have one of two conditions:
1. Low (under 8 or 9 V) at the stud - OR -
2. Good voltage ( > 9V) at the stud.
If the voltage is low, get a freshly charged battery or charge the one you have so you KNOW that it is good.
If the voltage is good, the solenoid should give a reasonably loud "click" and should supply battery power to the starter motor itself, and the engine will crank. If you get a nice click, but the starter motor does not turn, probably the solenoid points are bad. This is a lot easier to fix than replacing the whole starter motor.
If the starter motor whines (rotates), but does not turn the engine over, the solenoid is not pulling in, or the pinion is not engaging teeth on the ring gear in the transmission.
I do not believe that the various position sensors have yet been shown to be bad, since the engine does not crank.
If it turns over (cranks), but does not start, those parts would be suspect.
If battery and the other inline wiring checks ok, the starter is pretty easy conclusion when it just clicks. The solenoid tends to get a carbon build-up and or the plunger begins sticking. The starter on the UZ is under the intake plenum unfortunately. Plenty to take out before you can easily access it.
Wow hard to believe that this car has so much stuff tied together. I had it towed to Sewell Lexus and they worked on it for almost a day as the ecu wasn't acting right. Turns out all it was a loose connection on the alternator which after tightening the car fired right up! Thanks for all the suggestions. I am really lucky to have an excellent Dealer like Sewell near me as they are awesome!
Wow hard to believe that this car has so much stuff tied together. I had it towed to Sewell Lexus and they worked on it for almost a day as the ecu wasn't acting right. Turns out all it was a loose connection on the alternator which after tightening the car fired right up! Thanks for all the suggestions. I am really lucky to have an excellent Dealer like Sewell near me as they were awesome!
Thanks for posting back and sharing the information and detail on what resolved your problem. I agree Sewell is a class act among Lexus dealers.
2006 LS 430 Black Cherry w/cashmere interior. Premium Package. Lexus OEM power-point storage kit to replace console ashtray, Rear Sports option sway bar, Soundgate TOYPD2 Ipod adapter.
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