SC400 intermittent starting issues...
Thread Starter
Driver School Candidate
Joined: Feb 2011
Posts: 30
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From: CA
SC400 intermittent starting issues...
Can anyone help me keep my sanity? 
I too am facing the dreaded intermittent starting issues... Starter replaced, as well as battery, and wires from battery to starter/alt. about 6 months ago. Weird problem... Car ALWAYS starts on first try, even before replacing said parts... Problem is if I turn engine off within 5 minutes of starting, it won't restart. I may hear a subtle click, but the starter won't engage. I've tried wiggling coil wire, and sometimes that is enough to get the starter engaged again, sometimes not. I've tried placing key to the engine on position, and tapping brake, as well as moving gear selector from drive to park several times. Sometimes this will allow starter to engage again after placing in Park position? Battery checked and is holding 12.6V after allowing to sit for 6 hours+. I've also tried jumping from another battery when this happens to no avail... Especially weird, as car will restart again after letting it sit for 45 minutes or so...
Car is a '93 SC400 with 150k miles...
Any helpful suggestions would be appreciated. Bad contacts on the starter? Perhaps replacing coil or coil wires? Is there some type of relay or sensor that tells when the car is in N or Park that might be faulty? Faulty ignition switch?
I too am facing the dreaded intermittent starting issues... Starter replaced, as well as battery, and wires from battery to starter/alt. about 6 months ago. Weird problem... Car ALWAYS starts on first try, even before replacing said parts... Problem is if I turn engine off within 5 minutes of starting, it won't restart. I may hear a subtle click, but the starter won't engage. I've tried wiggling coil wire, and sometimes that is enough to get the starter engaged again, sometimes not. I've tried placing key to the engine on position, and tapping brake, as well as moving gear selector from drive to park several times. Sometimes this will allow starter to engage again after placing in Park position? Battery checked and is holding 12.6V after allowing to sit for 6 hours+. I've also tried jumping from another battery when this happens to no avail... Especially weird, as car will restart again after letting it sit for 45 minutes or so...
Car is a '93 SC400 with 150k miles...
Any helpful suggestions would be appreciated. Bad contacts on the starter? Perhaps replacing coil or coil wires? Is there some type of relay or sensor that tells when the car is in N or Park that might be faulty? Faulty ignition switch?
Last edited by Bott63; Oct 3, 2011 at 01:49 PM. Reason: spelling
If you hear the starter try to activate when you turn the key, chances are the ignition switch is good, as well as the park/neutral switch...
Toyota starters are pretty hard to hurt, but many times when your issue comes up, the contacts in the starter are in need of a good cleaning / replacement... they get burn marks from arcing and it eventually leads to high resistance across them... I know the starter is new, but that doesn't always mean it is good...
I would pull the starter and inspect... The parts are cheap, so I'd just replace them...
Coil and coil wires should have nothing to do with this - the starter should turn regardless what the ignition system is doing...
Other than starter contacts, I'd look in to engine ground wires and the lead wire from the battery to the starter - corrosion inside of one of these wires could easily be your issue... Maybe just replace them to be on the safe side...
Toyota starters are pretty hard to hurt, but many times when your issue comes up, the contacts in the starter are in need of a good cleaning / replacement... they get burn marks from arcing and it eventually leads to high resistance across them... I know the starter is new, but that doesn't always mean it is good...
I would pull the starter and inspect... The parts are cheap, so I'd just replace them...
Coil and coil wires should have nothing to do with this - the starter should turn regardless what the ignition system is doing...
Other than starter contacts, I'd look in to engine ground wires and the lead wire from the battery to the starter - corrosion inside of one of these wires could easily be your issue... Maybe just replace them to be on the safe side...
Dysfunctional Veteran
Joined: Sep 2004
Posts: 8,108
Likes: 324
From: Van Alstyne, TX
Ignition switches can be tricky devils. Check Relay's and Starter, but I would almost lay money on the ignition switch. Every time I have had one go out it does exactly what yours is doing for a few months, maybe a year...then it dies completely.
Thread Starter
Driver School Candidate
Joined: Feb 2011
Posts: 30
Likes: 0
From: CA
Thanks for the replies guys!
New battery, as well as new wires to starter, alt., ground wire several months ago. I've checked these again, and everything appears to look brand new still..
Park / neutral switch? Where would I find that on the car? I did get the car started again once after this happened, after turning key to engine on position, then switching in and out of gear several times, then activating the starter again... Could be this? Hmmm.
Ignition switch... Would that mean replacing the entire key section at the steering wheel?
Again, thanks everyone for chiming in!
New battery, as well as new wires to starter, alt., ground wire several months ago. I've checked these again, and everything appears to look brand new still..
Park / neutral switch? Where would I find that on the car? I did get the car started again once after this happened, after turning key to engine on position, then switching in and out of gear several times, then activating the starter again... Could be this? Hmmm.
Ignition switch... Would that mean replacing the entire key section at the steering wheel?
Again, thanks everyone for chiming in!
Dysfunctional Veteran
Joined: Sep 2004
Posts: 8,108
Likes: 324
From: Van Alstyne, TX
Thanks for the replies guys!
New battery, as well as new wires to starter, alt., ground wire several months ago. I've checked these again, and everything appears to look brand new still..
Park / neutral switch? Where would I find that on the car? I did get the car started again once after this happened, after turning key to engine on position, then switching in and out of gear several times, then activating the starter again... Could be this? Hmmm.
Ignition switch... Would that mean replacing the entire key section at the steering wheel?
Again, thanks everyone for chiming in!
New battery, as well as new wires to starter, alt., ground wire several months ago. I've checked these again, and everything appears to look brand new still..
Park / neutral switch? Where would I find that on the car? I did get the car started again once after this happened, after turning key to engine on position, then switching in and out of gear several times, then activating the starter again... Could be this? Hmmm.
Ignition switch... Would that mean replacing the entire key section at the steering wheel?
Again, thanks everyone for chiming in!
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Lexus Champion
Joined: May 2002
Posts: 2,781
Likes: 6
From: Georgia
When the car is acting up and won't start, just try to turn the key on(do not start) and look to see if you see the "Check engine light" on the combination meter comes on.
Sound like heat related problem because after you start it up for 5 minutes or longer then shut it off and the car won't start anymore. Either some relay or something got heat up.
Sound like heat related problem because after you start it up for 5 minutes or longer then shut it off and the car won't start anymore. Either some relay or something got heat up.
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Thread Starter
Driver School Candidate
Joined: Feb 2011
Posts: 30
Likes: 0
From: CA
When the car is acting up and won't start, just try to turn the key on(do not start) and look to see if you see the "Check engine light" on the combination meter comes on.
Sound like heat related problem because after you start it up for 5 minutes or longer then shut it off and the car won't start anymore. Either some relay or something got heat up.
Sound like heat related problem because after you start it up for 5 minutes or longer then shut it off and the car won't start anymore. Either some relay or something got heat up.
Anyone able to tell me if there is in fact, and location of some kind of "Neutral position" sensor that tells computer when the car is or is not in P or N for the car to start? If you guys were to place the trans in your car in gear, then attempt to start, this is the condition I face if the car is turned off soon after turning car on, then attempting to restart...
What makes me think it may be this switch even more, was what I experienced yesterday... Faced with a dirty car before going to an event 2 hours later... I placed cold car in neutral and pushed it outside of garage to wash it. Pushed it back in garage an hour later... When I went to leave 30 minutes later, the problem resurfaced... NO START! I turned key to "engine on" position, and moved gear selector in and out of Park several times. Still, no start... Let the car sit for 2 more minutes, then I was able to start!
Lexus Champion
Joined: May 2002
Posts: 2,781
Likes: 6
From: Georgia
Toyota/Lexus vehicles neutral safety switch located on the side of the transmission just above the transmission oil pan. You have to look for the big connector near by the shift linkage.
You may need to start to do your own diagnostic step by step. Next time when the car won't start you will need to check for fuel and spark. The car need compression,fuel,spark and air to run.
Since your car runs smooth if it start so we don't have to worry about compression(timing) and air.
You can remove the spark plug wire and properly ground it to the engine ground while your friend try to start the car and observe for the spark. If you get spark then your ignition system is good. Now move on to the fuel delivery system. Your main fuel line is located on the driver side of the engine,but very careful when check for fuel and make sure you wear safety glass and don't burn down the car or the house...lol.
You may need to start to do your own diagnostic step by step. Next time when the car won't start you will need to check for fuel and spark. The car need compression,fuel,spark and air to run.
Since your car runs smooth if it start so we don't have to worry about compression(timing) and air.
You can remove the spark plug wire and properly ground it to the engine ground while your friend try to start the car and observe for the spark. If you get spark then your ignition system is good. Now move on to the fuel delivery system. Your main fuel line is located on the driver side of the engine,but very careful when check for fuel and make sure you wear safety glass and don't burn down the car or the house...lol.
Driver
Joined: Jun 2006
Posts: 118
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From: Alberta
I wish I found this thread earlier. I am 95% sure your starter contacts are gone, its a common problem with the motor, and affects LS400 and GS400 guys. Unfortunately its an expensive and labour intensive job as the starter is underneath the intake manifold - budget between 5-600.
Hope you havn't replaced everything and the kitchen sink already, good luck!
Hope you havn't replaced everything and the kitchen sink already, good luck!
Thread Starter
Driver School Candidate
Joined: Feb 2011
Posts: 30
Likes: 0
From: CA
I wish I found this thread earlier. I am 95% sure your starter contacts are gone, its a common problem with the motor, and affects LS400 and GS400 guys. Unfortunately its an expensive and labour intensive job as the starter is underneath the intake manifold - budget between 5-600.
Hope you havn't replaced everything and the kitchen sink already, good luck!
Hope you havn't replaced everything and the kitchen sink already, good luck!