2001 Highlander, Compustar 1W900FM-S Cold Weather Problem

Hi everybody,

I recieved excellent help last year on purchasing the correct components for my wife's surprise Highlander remote start Christmas gift.  It went over really well with one hitch...

The RS unit is a Compustar 1W900FM-S.  The Transponder amplifier (Crimestopper TATAII) doesn't seem to be doing it's job when the temp gets below freezing out.  Naturally this is the time that the remote start is most welcome.  I get three failed attempts to start without the OE security light extinguishing.  I have installed everything correctly and placed the antenna loop as concentrically and as closely as possible around the key ring reciever.   BTW, I'm a Toyota mechanic, so the physical work, transponder diagnosis and wiring stuff is a non-issue, just the newish concepts of remote start integration : )

Could I have selected a poor quality transponder amplifier?  It was $10 less than the other brand that was offered (I think it was a DEI unit).  I can't imagine that this antenna loop could get any closer to the key reciever given the steering wheel shroud design.

Does anyone have any ideas?

Thanks, I'll post any progress as it happens!

So your saying the transponder bypass will only work when its warm? If so what may be happening is when it gets cold it is moving just enough not  to work maybe try hot gluing it in place or any method of securing it in a place were it works.

Velocity Motors wrote:

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The location of the key inside the box that you used will play a big part in the signal being picked up at the Immobilizer. Make sure that the key didn't move around in the box and then try to start the vehicle again with the key in a different spot in the box.

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That's very interesting.  The key could not likely have moved as the foam-filled box design really clamps down hard on it.  Perhaps it has never been in the best position to begin with.  I will try moving the key around in the bypass unit, though I can't remember right now if there is much room to play around with.

Have you ever experienced this same cold temp related bypass issue before?

Thanks,

Tony

xtremej wrote:

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So your saying the transponder bypass will only work when its warm? If so what may be happening is when it gets cold it is moving just enough not  to work maybe try hot gluing it in place or any method of securing it in a place were it works.

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I used small tabs of electrical tape to secure it before basically smashing the loop into place with the steering shroud.   This problem seems to have been happening since the first really cold day last year.  I can check the position again and try the hotglue method if necessary.  That is a good idea.

Thanks,

Tony

Chris Luongo wrote:

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If the steering shroud doesn't fit acceptably, you can carefully cut the plastic covering off the transponder bypass ring, and then hold the ring back together with a little bit of electrical tape.........this makes it thinner, and the shroud will fit better.

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Thanks, Chris.  Yes, I'm sure it is a weak transponder signal issue, though I'm so used to Toyota diagnosis and spend so little time paying attention to our own cars that I must admit it was a one-time split second descision to condemn the bypass unit.  I haven't tested it formally to verify but can double check tomorrow if it is cold enough out.  I will get in, verify it doesn't start, then hold another transponder key up to the ig cylinder and retry.  Of course I could actually be losing power from the Compustar module to the power input on the bypass.  It just seems more likely that this is a broadcast issue given it's temp related.

Regarding stripping the plastic insulation off of the antenna loop, are you experienced with folding up the bare copper braid so as to reduce the resulting diameter to that of the key cylinder?  Would this folding have a negative effect on performance?  Would bare copper in this location suffer from the typical dust and other crap that always builds up under interior trim panels?  Another poster mentioned hot glue which sounds like a great idea too (in moderation!)

Thanks,

Tony

Yup, I just verified it's the transponder bypass that isn't operating properly.  Better to be informed than ignorant : )

I will try all of the above suggestions this week and let y'all know how it works out.

Thanks,

Tony

Hi,

My original topic has been closed so I can't reply to it, but you can see it here:

https://www.the12volt.com/installbay/forum_posts.asp?tid=86542&KW=2001+highlander

I forgot to follow up on it in a timely fashion, but here it finally is -- Belated thanks go out to xtremej, Velocity Motors, and Chris Luongo for getting me on the right track with our 2001 Highlander no remote start when cold issue. Right after I got the advice to reposition the transponder amplifier antenna loop, the weather here got insanely warm for weeks. Then I forgot about it, then got too busy. A couple months ago I got the chance to fix the problem and verified the result over a few sub-freezing days.

The antenna loop had a clear spiral plasic sheath over it, so it was really easy to remove. I just pulled off the steering shroud, unwound/removed the plastic around the braided copper loop, and then tightly wound the bare wire loop around the key cylinder, but right on the face of it up above it's shoulder. Now if you look carefully through the key cylinder cutout in the shroud, you can see the copper wire, but it's a small price to pay for trouble-free operation.

Thanks again, guys!

Tony