Lexus Mobile Cell Phone And Loss Of Sound From Speakers

[bossman]

I have a 1997 Lexus LS400 with the built-in Lexus mobile celluar phone in the armrest.

While driving today, I heard some beeps about every 20-30 seconds (the sound of the beep was identical to the beep that I hear when I turn the ignition on and the phone is activating). The beeps were becoming annoying, so I pushed the "pwr" button on the handset and the beeping stopped.

I then turned the radio on, and there was no sound coming from any of the speakers. I tried am and fm radio and the cd player - no sound. Only when I turned the volume knob to the maximum can I hear a faint sound of the music playing.

I have also noticed that the display screen on the phone handset now is completely dark. Even when I push the "pwr" button it will not turn on. Previously it would give an indication of signal strength. When starting the engine, I no longer get the familiar beep of the phone activating.

I did activate the phone for use when I bought the car (used) 2 years ago, but do not use it now.

Help! How do I get the phone back on if pressing the power button does nothing? Were those beeps warning me of something? Maybe a blown fuse? And how can I get the sound back for my stereo? It is almost as if the stereo has been muted because of an incoming call.

Any assistance you can provide would be appreciated. Thanks!

[SKperformance]

does it work if you remove it from the cradle?

[bossman]

Hi SKperformance,

The phone will not work if it is in the cradle, or taken out.

[jbarhorst2]

I think he means your stereo. Does your stereo work when you remove the phone from its cradle??

Tom

[SKperformance]

no , i meant the phone.

No i am going to ask if the radio works when the phone is removed.

Try startign the car and turning it off between changes.

[jbarhorst2]

Sorry SK.

Edited December 18, 2005 by jbarhorst2

[SKperformance]

no need to say sorry it wasn't made clear by me anyway.

[bossman]

Hello SKperformance,

I have removed the phone from the cradle and started the car several times, and the stereo has no volume unless totally cranked (and then you hear the music faintly). This is the same as when the car is started with the phone in the cradle - no difference.

The phone appears to be completely "dead" as it previously could illuminate the key pad, and as mentioned before the lcd display screen would have some sort of display - now completely dark.

Could this be a fuse for the phone only? Or a possible phone programming issue? Help!!! i am going a little stir crazy with no music in my car.

[1990LS400]

Bossman,

The following answers are based on a 00 LS so yours may be a little different.

Your dead phone system may be permanently grounding the mute connection to your audio system - almost all car phone systems use this same grounding principle. If you mainly want to get your radio working here are two things to try.

Locate the phone transceiver in the trunk and disconnect the two large connectors from it. Plug the two connectors together so that the transceiver is bypassed. If there are any other connectors from the wiring harness into the transceiver, you might as well unplug them too.

If that does not restore the radio volume, unplug the phone handset from the connector(s) under the console vents - the vents you see when the console lid is raised. Doing this will require some minor disassembly of the console.

If that doesn't work, you might need a "pro".

[bossman]

Hi 1990LS400,

Thanks for those tips ... much appreciated. I pulled out my factory repair manual (I knew this would come in handy some day) and found some diagrams of exactly what you described as far as disconnecting the transceiver. This should bypass the muting effect and restore the stereo ... fingers crossed.

I still don't understand why the phone went completely dead, though? I have contacted my local Toyota dealer and they have a call in to a Lexus dealer (no local dealer - closest probably 3 hours away) to get me more info on what might be happening.

Again, appreciate the info ... this board is great for getting good advice.

[1990LS400]

I just checked the fuse box under the hood of my 00 LS and found a 15 amp fuse for the phone - the fifth fuse from the right on the front row - possibly different on your 97. My repair manual seems to indicate more than one fuse for the one so there could be one under the dash - the legend on the fuse box cover should say.

Good luck!

[bossman]

So I've found some free time to investigate this problem ... and it is getting bigger! I checked the trunk where the transceiver, speaker relay and noise filter are located. The area is wet!

I trace this back to a problem I had back in July 2004 where water was getting into the trunk. I took my car to the local Toyota dealer and they removed, cleaned and reinstalled the trunk seal. Whatever they did has not stopped water from getting into the trunk - and before it would just collect in the spare tire well ... now it is getting into the electonics for the cellular phone.

So I checked the enine compartment junction block and sure enough the 15A fuse for the telephone is blown. I guess water and electricity really don't mix. I stuck in a spare 15A fuse and it blew as soon as I started the car.

Then last night as I was driving the ABS warning light came on, which I thought was odd. The steering also got very heavy, as if the power steering had cut out.

In checking the electrical wiring diagram for this cellular phone, I noticed that there was a second 15A fuse located in the instrument panel junction box inside the car. Pulled this fuse, sure enough it was blown too.

This ECU-IG fuse not only has the telephone on it, but also the ABS system, traction control system, charging system, power steering conrol system and shift lock.

So I am now without ABS and power steering, and when I went to start the car this morning I was unable to get it out of Park (shift lock). I plugged in a spare 15A fuse into the ECU-IG, started the car and got it out of Park before the fuse blew again. I drove it straight to my Toyota dealer and it is sitting there waiting for service tomorrow. Had to put it back in Park to get the ignition key out.

So once they get a new trunk seal properly installed and the electronics dried out, hopefully I'll be back to happy motoring.

[ty62]

Howdy!

I am a newby on the forum, and this trhead seemed the closest to my problem. have a 92 LS400 that we owned for 8 years. we did not use it for a few months, and when we wanted to start it up, the battery was drained, so i have charged it up (revived nicelly) and when i sat to start it the built in phone that we never used or activated started to beep, and the stereo was muted. The car started and everithing works on it except the stereo seems like it is on mute, if i crank it up I can sort of fear the music (all aspects of the audio and CD works) but the power is extremelly weak. Yook it to Lexus (JP Lexus In North vancouver) they are good people, tech disconnected the phone, but the stereo is still muted, they can not fix the problem, the only suggestion they had is to take the deck out and giv it a try to have it repaired by 3rd party. The power amp works as on high volume a hiss is comming out of all speakers, and I can hear the music from all channels, but it is so dim sound like it is on MUTE. Oh yes it is a Nakamichi system.

Amy ideas will be appreciated

Tnx

Ty

[1990LS400]

An authorized Lexus dealer can't diagnose the problem? Geez, that's why we give them the big bucks.

It does tend to sound like your now phantom phone is still muting your radio - as if a call is in progress. The tech should have plugged the two large phone connectors in the trunk from the phone ECU and then plugged them together. The handset in the arm rest should also be unplugged (do not cut the wires!) since there is also a radio mute pin in the phone connector under the air vents you can see when you raise the arm rest. Unplugging the handset requires minor disassembly of the center console -- search for a thread from Blake918 which shows the under console connector in his similar 95 LS.

[ms1205]

I have the same issue n my 1992 LS400. I recently unplugged the unused cell phone as it was taking up space I could use. Are there also plug the are in the trunk on a 92? If so, where do I look? 328,000 miles and it still looks and runs great. ( Thanks to you guys for endless help. This sight is full of great ideas and great people! Thanks.