Lexus sc430 retractable roof failure
06-13-18, 07:08 AM
#1
Driver School Candidate
Thread Starter
Lexus sc430 retractable roof failure
Hi everyone
I have a problem with my roof , i have a 2002 SC430 , had it for 12 years no problem , the roof goes down , then when i put it back up it stalls for a couple of seconds , then closes , once closed its dead !!! if i leave it for a few days its fine to open but then the same problem .
Its smooth when it works , but the problem happened once , then i disconnected the battery over night , checked fuses , then reconnected the battery . it worked for about two weeks , then it did it again , this time no luck , then three days later it worked , stalling again on closer , but did close .
tried diconnecting again no joy . when it refuses to open the open close switch does not illuminate !!!!
is this a common fault and a trip to the dealer
I have a problem with my roof , i have a 2002 SC430 , had it for 12 years no problem , the roof goes down , then when i put it back up it stalls for a couple of seconds , then closes , once closed its dead !!! if i leave it for a few days its fine to open but then the same problem .
Its smooth when it works , but the problem happened once , then i disconnected the battery over night , checked fuses , then reconnected the battery . it worked for about two weeks , then it did it again , this time no luck , then three days later it worked , stalling again on closer , but did close .
tried diconnecting again no joy . when it refuses to open the open close switch does not illuminate !!!!
is this a common fault and a trip to the dealer
06-13-18, 10:34 AM
#2
Lead Lap
When it stalled on closing, at what point in the process did it stall? Does it make a difference what the weather is like outside (i.e. does it fail when it is hot or cold or rainy)? Does it ever not completely close or does it close and then just not open again?
I'm guessing that there is a dirty contact or switch at the bottom of this.
I'm guessing that there is a dirty contact or switch at the bottom of this.
06-13-18, 10:49 AM
#3
Driver School Candidate
Thread Starter
Hi Harold
Thank you for your reply , well so far the weather has been hot here , 25c, it has always closed after stopping halfway through the closing procedure ,almost as if it resorts to a failsafe mode , it stops for a moment and then starts again and closes , it beeps but dosnt complete the window closing stage . after that it is dead with the open close switch not illuminating.
it then may open a few days later , opening is as normal when it does work , and it is a smooth operation. all fuses have been removed and re installed , there is a cable/wire on the hinge at the base of the rear window that seems to come out of the runner but even if i replace it in the runner nothing happens
Thank you for your reply , well so far the weather has been hot here , 25c, it has always closed after stopping halfway through the closing procedure ,almost as if it resorts to a failsafe mode , it stops for a moment and then starts again and closes , it beeps but dosnt complete the window closing stage . after that it is dead with the open close switch not illuminating.
it then may open a few days later , opening is as normal when it does work , and it is a smooth operation. all fuses have been removed and re installed , there is a cable/wire on the hinge at the base of the rear window that seems to come out of the runner but even if i replace it in the runner nothing happens
06-13-18, 11:03 AM
#5
Moderator
Do you have access to a diagnostic trouble code (DTC) reader? There are about 50 error codes which will point out the problem. From your description, an intermittent one, it’s more difficult to figure out what’s wrong. Once we figure out the codes we can do a good job determining the repair thus avoiding high dealer fees. And, sort of agree with Harold, dirty contact at a switch, but there are several.
06-13-18, 11:46 AM
#6
Driver School Candidate
Thread Starter
Hi Bob
Yes your probably right , the car does not get used a lot to be fair , she has only done 25,000 miles , although i do go out and open and close the roof now and again , but no i dont have a DTC
Yes your probably right , the car does not get used a lot to be fair , she has only done 25,000 miles , although i do go out and open and close the roof now and again , but no i dont have a DTC
06-13-18, 11:49 AM
#7
Driver School Candidate
Thread Starter
technically im not great , although i have just replaced the japanese sat nav and radio/cd player with a UK version today , and i feel that was a result !!! she is a japanese import , toyota soarer , same car though
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06-15-18, 05:16 PM
#8
Bob is always right 
Here is a quote from one of Bob's posts a few years ago which is a great summary and may help you understand the process:
When I had a problem, I went to the Lexus dealership and sat in the parking lot for an hour putting the top up and down until the problem occurred. Then they came out, read the codes for me, I gave them $75 (the deal we worked out) and buh-bye. Came to this forum with the codes, got great advice, and did a true repair, whereas Lexus would not have done a repair of the existing part but rather a replace. Convinced I saved about $2,000.
Here is a quote from one of Bob's posts a few years ago which is a great summary and may help you understand the process:
Okay, the first issue is the lack of readable trouble code(s). Unfortunately they are not stored. The reader must be attached when the error occurs. Most generic readers won't pick up proprietory or Lexus manufacturer specific codes. However the codes ( B2501-2554) point specifically at paticular, switch(es), motor(s), or pulse counts communication errors. Which helps with the diagnostician locate the problem area quickly.
As we all know the roof is a wonderful piece of engineering with a large number of moving parts, switches, and motors. They're all tied together through a communications system which "talks" to all the moving parts, monitoring the motors and switches, counting pulses keeping the left and right sides in sync for proper operation. There are also low speed positions gradually increasing to operating speeds for the roof. Slower ops occur at the beginning and end of each open and close cycle designed to minimize, vibration, wear and tear.
Johnny your description reads like the roof's ECU is going into fail safe mode and, not to be Dr. Obvious here, tied to the luggage links 4 and 6, the motors and switches that interface with it. An intermittent failure, or more likely the pulse count between the left and right sides varies and the ECU stops the operation. Another possibility from your description is one of the switches is not sending a signal, when expected, and the operation is stopped.
Since you've also said this only happens a small percentage of the time, and trouble codes are not stored in the ECU after a successful cycle, the error needs to happen at the dealership. So your best course of action is to see if you can specifiacally replicate the circumstances REPEATEDLY so not to waste time, effort and your money at the dealership.
As we all know the roof is a wonderful piece of engineering with a large number of moving parts, switches, and motors. They're all tied together through a communications system which "talks" to all the moving parts, monitoring the motors and switches, counting pulses keeping the left and right sides in sync for proper operation. There are also low speed positions gradually increasing to operating speeds for the roof. Slower ops occur at the beginning and end of each open and close cycle designed to minimize, vibration, wear and tear.
Johnny your description reads like the roof's ECU is going into fail safe mode and, not to be Dr. Obvious here, tied to the luggage links 4 and 6, the motors and switches that interface with it. An intermittent failure, or more likely the pulse count between the left and right sides varies and the ECU stops the operation. Another possibility from your description is one of the switches is not sending a signal, when expected, and the operation is stopped.
Since you've also said this only happens a small percentage of the time, and trouble codes are not stored in the ECU after a successful cycle, the error needs to happen at the dealership. So your best course of action is to see if you can specifiacally replicate the circumstances REPEATEDLY so not to waste time, effort and your money at the dealership.
06-15-18, 10:04 PM
#10
Wow. VVTiBob and JohnnyCake.
I learn so much here. I had no idea there were really proprietory / mnfr specific codes. That explains a lot.
glenn120 I hope you can easily get your top fixed. Thanks for posting to let everyone else learn.
Really appreciate reading everything here.
I learn so much here. I had no idea there were really proprietory / mnfr specific codes. That explains a lot.
glenn120 I hope you can easily get your top fixed. Thanks for posting to let everyone else learn.
Really appreciate reading everything here.
08-09-18, 07:14 AM
#11
Roof issues
I just bought a 2002 SC 340, Black Cherry. Alternator went, replaced along with new belt, and everything was great for a month. Then, roof stopped working. I read thru all the threads, checked the fuses and everything else mentioned. Bought a used part on eBay and installed it...did not work. Read that if all else failed, disconnect the battery to reset. My son the computer wizard suggested we retry the old part as it had been disconnected for 2 hours and looked to be in much better condition that the one I got on eBay. And what did we have to lose while we had the trunk apart! It worked! Not saying it would work for everyone, but it’s worth a try!
08-09-18, 10:35 AM
#12
Lead Lap
I just bought a 2002 SC 340, Black Cherry. Alternator went, replaced along with new belt, and everything was great for a month. Then, roof stopped working. I read thru all the threads, checked the fuses and everything else mentioned. Bought a used part on eBay and installed it...did not work. Read that if all else failed, disconnect the battery to reset. My son the computer wizard suggested we retry the old part as it had been disconnected for 2 hours and looked to be in much better condition that the one I got on eBay. And what did we have to lose while we had the trunk apart! It worked! Not saying it would work for everyone, but it’s worth a try!
Welcome to the forum.
10-29-18, 10:26 AM
#13
Driver School Candidate
Thread Starter
Can anyone tell me if when you replace a roof control unit ECU on an SC430 , is this a plug and play or does it have to be coded ?
thank you
thank you
10-29-18, 11:23 AM
#14
Pole Position
10-30-18, 05:51 AM
#15
I replaced mine with a used part which did not work. The original part was reinstalled after being out for about 2 hours. Reinstalled the old part without doing anything else and it worked perfectly and has been working for 3 months now!
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