AM Radio Interference

A couple of questions: first, does the distortion happen with FM or the CD player? Second, is there any pattern to the problem? like rapid acceleration, gliding, ICE on, ICE off, location in the city, etc?

There is no, repeate NO possible direct path from the HV system to the radio... the only paths that exist go through the inverter to the 12V system (if that was bad, you'd have a lot more problems), and through sensors to the computers to the MFD/radio... either way, there shouldn't be anything "burning out" that causes it. A guess would be that there's a loose connection somewhere between the radio and the antenna, allowing it to sorta "short out" on the car frame... That could account for the static.

Give us some more specifics, and we may be able to better diagnose potential sources for the problem.

 

Only when the ICE is engaged? tahts a bit odd, but it does tell us that it's probably not the HV system or the electric motor thats the problem (since those can, and normally do, run at times when the ICE does not).

I'm guessing you probably won't get help here for this particular problem... it sounds really hard to diagnose. anyways, take it in to your dealer and see what they have to say (especially if you're still in your original warrenty). It'll take a good diagnostic tech to figure something like this out... just thinking through it i can't think of anything that would cause it.

maybe your car is just mad at you for using gas :-p

 

MarinJohn, from your first post, I thought it was the same problem I have. When I have AM on, charging or discharging current from HV battery, and when reception is poor (due to location), I will hear a faint high pitch noise from the speakers. FM doesn't have this problem.

My explanation to that is when the signal to noise ratio for AM signal is low enough (bad reception areas), and the auto gain control circuit amplifies the signal mixed with noise, you will hear this faint high pitch noise created by current going thru the cable between the battery in the back and the electric motor in the front of the car. Basically, it's a shielding problem. If there's enough shielding on the cable carrying high current, you will just hear white noise on AM if reception is bad. I can reproduce this every time when I travel thru a section of road with bad AM reception (under the bridge for example). I have not had this problem on FM due to high signal to noise ratio of FM modulation.

You were saying the problem go away when you shift to N. When you shift to N, the battery is not being charged or discharged, therefore no interference. Makes total sense up to this point.

Your second post said that there's no pattern and problem is there when ICE is engaged. Now that throws me way off. It is completely different than my assumption that your problem is caused by the interference of the current going in/out of the HV battery. Can't think of anything else at this point. Sorry~

 

Toyota has in the past manufactured a few kits for AM radio interference. It's a direct plug-in to the back of the radio (pass through for the wiring harness).

I don't know if one is available for the JBL 6-CD system. Check with your dealer; ask them if they have the Audio handbook, it's kind of an obscure item to locate. If you had the base model radio, I could probably locate the part number...

Nate

 

<div class='quotetop'>QUOTE(MarinJohn @ Aug 22 2006, 07:53 AM) [snapback]307498[/snapback]</div>

Does it happen all along the AM band?

 

I also have a whine in the AM radio when the car is moving - from the comments so far, it looks like bad connectionsfor the ground or shielding. I have the stock radio with a single CD player and the problem doens't seem to be noticable on FM.

I do plan on installing my HF amateur radio gear in the fall (Phoenix at this time of year doesn't make outdoor installations any fun). I will post anything that I find with that installation.

Russ Kinner, WA8ZID
Surprise, AZ


<div class='quotetop'>QUOTE(MarinJohn @ Aug 22 2006, 02:16 PM) [snapback]307793[/snapback]</div>

 

I also have the same problem with the static in the AM radio. I have found that the static gets worse when I step on the brake or gas (more so with the brake). I can step on and off the brake while driving and the static gets worse then better then worse as I step on it again. It is also worse some stations more so than others. I have it at my dealer for the third time as they are trying to find the problem. I think they have replaced everything in the radio system. (radio, antenna, antenna cable, antenna base). Kinda reminds me of years ago when you needed resistor spark plugs or needed to stick a resistor in the electrical system to get rid of static. Certainly is a problem tho since sometimes it is unbearable.

 

See my new post here for my theory on this

http://priuschat.com/Static-on-JBL-premium-radio-t9400.html


Ron

 

has any one of you with this problem had the dealer change the antenna amplifier? that would be my first suspicion when there is a problem with AM reception. Either it's not grounded properly or the antenna leads are not properly connected. It's up in the dash behind the clear lucite panel rear center of the car.
Edit I'll try and cut and paste the location from the manual.

 

here's the picture and the location is A23 well it won't let me upload a 50KB picture of the location. PM me and I'll send it to you.

 

MarinJohn- What was the solution for this problem? It has just started happening to me. I get static anytime that I am not in neutral or gliding.

 

I have the exact same setup, '05 Prius with 6CD changer with the same problem, ie. AM radio interference. Did anyone come up with a solution?

 

I doubt that you will get any answers from the original participants.......in a 12 year old thread.

Typically that problem is caused by the antenna, antenna cable or a bad ground.

Of course it could be the radio itself too.

 

There's 2 filters. One is in the engine bay and another is attached to the antenna.

Has your car been in a rear end accident and bodywork performed in the rear of the car? .

 

WOW, you guys completely glossed over the one response that was actually correct....

Also read this thread.....

Radio Antenna Preamp Analysis | PriusChat

All you need to do is replace the preamp, it's not that hard to do on a Gen II.
If you can't do it yourself, the dealer will be happy to help....

 

I did no such thing. That's pretty much exactly what I said, although I left out the part about a possibly defective amp......which IS part of the antenna.