JohnnyCake

Of course, now that summer is finally here, I'm getting a roof issue. Strange symptoms that I've not seen posted here before. Wonder if anyone has any ideas before I take it to the dealership, as I fear they may make it worse.

My problem manifests itself in one of two ways.

OPEN: Process begins, but fails (stops) at the very beginning when front of trunk is maybe four inches up.

CLOSE: Process proceeds normally, but fails (stops) at the very end, when the front of the trunk is maybe four inches up.

In either case, letting off the button (which is red, of course, since the cycle is not complete) and then pressing the button again permits the open/close process to complete.

This is an intermittent problem, maybe 15% of the time. I've taken the positive terminal off the battery for 20 minutes, said a prayer to the goddess of the top, and then re-connected it, but that didn't seem to help at all.

Any ideas what the problem may be? If I have to take it to the dealer and there no codes have been thrown to point them in the right direction, I am really fearful of what they may do.

bacardi

this sounds like something for BOB.

VVTiBob

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. Of course, there's the other delimma you'll face. They're going to say it's the LL. You can argue the battery reset technique rules it out.
Sorry I'm not more help on this one...if you like, I can send (PM) you a list of the trouble codes (listed above) so you can ask them if they captured a code and you'll know what it means.

mrblister

Does the top exhibit the same faiure if you use the luxlink ? Instead of the dash switch. Or does it fail with the double press or the press and hold.. ?

JohnnyCake

Yes, exhibits same symptoms using Luxlink instead of dash switch or using Luxlink with double press or press and hold on dash switch. Physically removed Luxlink entirely and symptoms also the same.

Upon error, I am getting DTC code B2536, indicating fault condition: "Luggage compartment door courtesy switch malfunction" (Thanks for the code list, VVTiBob!))

My first thought was this was the Tonneau cover cover switch (the one where the top won't work unless the cover is in place). But there is a different code for "Limit switch (Tonneau cover) malfunction." On the other hand, there is also a code for "Limit switch (Package tray)" so maybe "limit switch" does not mean the check to make sure the Tonneau cover is in place.

Also, if it is the "Tonneau cover in place" check, it is odd that the top starts and then fails moments into its operation (e.g. when trunk goes up about four inches). You'd think that it would not start in the first place.

QUESTION ONE: Anyone have any guesses what "Luggage compartment door courtesy switch malfunction" means?

Also, from the pages VVTIBob gave me, the behavior (not the fault code) matches a "Motor Locking Condition." This is defined as "Motor locking condition is detected by current increasing to motor. ECU corrects the current at motor locking depending on outside temperature."

QUESTION TWO: Any thoughts on what is meant by "motor lock?"

Many thanks -- I'm desperate -- the SC430 with the top up is just another car!

VVTiBob

Well this is sort of good news...it's NOT a hinge or hinge motor.. it's the luggage door lock/sw, the wire harness or the roof ECU... What year is your car?

VVTiBob

Johnny: Check the email I sent stuff to last week.... I sent more on the 2536 error...

VVTiBob

Yes... it's the switch which is part of the luggage door locking mechanism....but the fault could be in the wire harness, one or both ends, the switch or the ECU... I sent you testing material.

VVTiBob

So after doing some more diagnostics on the cable, making sure there is no oxidation on the connector pins/connection ... it probably is the switch BUT YOU NEED TO TEST the continuity and then RESEAT the WIRE HARNESS before getting a new switch

I am finding two part numbers so you may have to check and see which number is stamped on yours.

84290M SWITCH ASSY, LIMIT(FOR LUGGAGE FRONT LOCK LH)
84290‑24080 UZZ40, NO.1 1 $91.84
84290‑24090 UZZ40, NO.2 1 $68.68

VVTiBob

This should help you too...

JohnnyCake

What we Americans would call the trunk latch? So it thinks the trunk is open and thus faults?
Not sure why they call that a "courtesy switch."

This makes much more sense than the tonneau cover not being in the pull out blind. From the stuff you sent me, that is an operating condition prerequisite, meaning that the top should not work at all rather than fault.

Did not receive anything today -- resend? Have time to test tomorrow so that would be great.

VVTiBob

Sent again along with a BCC to one of my other email addresses and has already arrived there.

VVTiBob

I believe you should see two switches. One should stop any operation when an improper state is detected, the other monitors tilt, open and close. It's also a reason to be concerned about an intermittent ECU problem, but could be as simple as a loose connection, oxidation on/at the wire harness connection points.

VVTiBob

Johnny,
Check this site for part numbers
http://www.*******.com/parts/p_U_200...KA_8401.7.html

KBALL

^ The Guru