Mickminer

This has been an intermittent failure for a few years but it is getting worse. The radio will change from xm to fm to am. It will turn off and on. I have turned it off today while my non connected cell phone was ringing. So that I could hear, I turned the radio off. It kept coming back on. I am reasonably mechanical and have considered shorts and bad ground wires, but this is stranger than the obvious. Very smooth roads with no bumping or left to right swerving and the radio will change or go off. On a very bumpy road, swerving and bouncing, and it is fine. Turn on a blinker and the radio will change or go off. The navigation has been fine and the climate system seems unaffected as well. I have returned to my locked car and had the windows all down and the sunroof open, but in reading other threads I expect this is being triggered by the key fob and unrelated. So, we have the typical issue of, " how to fix a problem that doesn't appear to be failing". A dealer will hunt for days for a short that I don't believe exists. I would certainly pay to have this fixed but the labor cost to find a gremlin may be a waste. Anybody got any great ideas? Maybe it's a computer program update... wow that would be easy!, thanks for your comments.

vlad_a

Try disconnecting the battery for 15 minutes - maybe a nice reboot will help.
If the blinker sets it off, I'd try looking for a bad ground. It is possible blinker and the steering wheel controls share the same harness and it may need to be replugged.

Mickminer

First of all, thank you vlad for responding to my issue. I will disconnect the battery as you have requested. The steering wheel issue arose again today. I came out to my car in a parking lot and started the car and the radio was blaring loudly. The volume control did nothing. I swiveled the steering wheel and tried the volume control again and it worked. I believe there may be some significance to this however, do you think it will require removal of the whole steering column or is there a plugged electrical harness somewhere under the dash that leads up into the column? And will unplugging it temporarily open the circuit so the steering influence can't be tested? Thanks again for the assistance.

vlad_a

N/p, mate! Good call on getting steering wheel controls out of equation. I cannot confirm or deny as to where the harness for the steering wheel controls is, as I have no manuals to look it up.
However, you can signup for Toyota TIS and get yourself a set of wiring manuals:
https://techinfo.toyota.com/
They would come pretty handy to try to figure this out. I don't think there's a need to remove the steering wheel column, as you can figure out which connectors and wires go where with the wiring diagrams. You can probably intercept them at the headunit itself, if the signals are not sent via digital CANBUS interface shared with other systems.

Mickminer

Thanks vlad, I'll look into getting those wiring diagrams.

MikeInOr

My 2010 450h will do similar things on hot days in the summer after the car has been sitting in the work parking lot sun all day. At first I thought it was the steering wheel but came to the conclusion that the problem is in the radio. This happened a few times in the summer but not enough to do much about it. I am sure it will eventually get to the point where it is annoying enough that I am compelled to look into it.

I believe I read the low and middle line radios are made by Pioneer? Of course the top end is Mark Levinson... I wonder who actually manufactures the Levinson unit? I have the middle tier radio (head unit), which radio do you have?

I have noticed several posts of people reporting similar problems... so I don't think the problem is all that unique or specific to the RX model line.

mcomer

Might the steering wheel control buttons - mode, up/down and volume have been damaged?
Spill a liquid on them, blunt force trauma? Seen buttons that stick after being pressed
and causes very weird symptoms. Turn or shake the wheel...button pops and all's well
till it happens again...random is tough to track

Mickminer

I appreciate the feedback. I wish it were as simple as spilled liquid on the buttons, but nothing ever spilled and this has always been an adult only car. And I find it hard to believe that the radio could be bad when the stations change when I change climate control fan speeds. This is a very weird interconnected issue with grounding or inconsistent amperage or voltage through some circuit boards. I think the best fix might be an Audi q5. From looking around this chat area, it appears Lexus has many strange electrical issues. There is nothing harder to fix than intermittent failures such as these.

vlad_a

If you think Lexus has weird issues, wait 'till you fix it with an Audi.
For example, in my Audi, they ran audio/video signals using fiber optics. Fiber optics are great at stationary data centers and not so much in moving cars. There's a Pioneer reverse camera unit in the trunk that occasionally fails to send digital camera signal, so the reverse camera is reporting errors and has distortions in the picture before it turns itself off. Then there's the engine. Having a direct injection and no port injection, it will need a nice carbon cleaning of the intake valves around 40K mark, just at the warranty runs out. I could keep going, but I think you get the picture. That's why we have a Lexus and an Audi in the garage - one is practical and the other is fun.

Mickminer

yeah, thanks for that vlad. It was a figure of speech really. I think technology has made our cars incredible engineering feats while also making them overly complicated when failures occur. My thoughts are that the difference between the designers and the end users many years ago was the separation of a little understanding. The general operation of automobiles could be explained to anyone minimally mechanically minded. Today the difference between designers and end users is a cavern uncircumventable. They have become so complicated, I don't think the engineers know what each other's components do or how they may be interconnected. Remarkable technology advancement has moved the shade tree mechanic into the history books. Hell, half the time, the auto dealers can't fix the problems.
However, with regard to your direction from a couple days ago, I will disconnect the battery for what it's worth this evening. Maybe a reboot of the computer will help.
PS. And just think, in just a few more years, we won't even be driving these things. Do you think the driver that's not there can open the hood and fix the problem that's........not there. ��

vlad_a

There is one thing that scares me more than that - spaghetti code.
And with proliferation of computers and software, it's everywhere.