Weak FM radio reception in 2010 Prius?

Tande,

There is something wrong with your radio system. Or your car. Or both.

I'm about to hypothesize like crazy. One or none of the following guesses may be correct.

First: I'd be very curious to know the characteristics of the "Phzzzit, phzzzit" you're hearing. You've already said it doesn't sound when you're sitting still. Does it vary with road speed? Does it vary with engine speed? Does the frequency (that is, how often) it comes up vary with anything identifiable on the engine display? Is it a constant; that is, the occurrences don't vary once they start? In which case, how often are they?

I guess at two, maybe three possibilities here. First, if the signal through the antenna or in the first stage in your radio is severely attenuated, then, with a weak signal, any kind of periodic EMI (elecromagnetic interference) will overwhelm the weak signal and give you what you're hearing. In ye olden days, back when high-voltage spark plug systems were coming into the vogue, you could tell when somebody hadn't put either resistive spark plug wires or resistive spark plugs in their car or that little condenser on the distributor had failed: When one would rev the engine, you could hear the "bzzz" of the spark plugs spark plugs firing. One would especially notice this on the AM band. Priuses don't particularly have that problem (or shouldn't), mainly because the coil and all that are integrated right on top of the spark plugs. However, if you can hear that noise of yours cutting out when the car isn't moving or if you're running some short distance in stealth mode (when the sparks aren't firing), then that noise may be the source of your signal.

The other possibility has to do with the switching transistors that drive the two motors in the car. They switch a heck of a lot of current, and that switching can easily create EMI that varies as engine rotation; however, my cursory inspection of the car shows that the switching boxes are pretty thoroughly shielded. Still, if you get this noise whenever the car is moving and it doesn't cut in and out, then that could be the root source of the noise.

Now, I don't notice this stuff on my car at all. This leads to two possibilities:

1. Your radio signal is snackered. If it's really weak due to blown transistors, bad solder, you name it, then whatever electrical noise is present in the car is going to come through. We could be talking about bad amplifiers in the antenna; a fouled up radio; or even bad connectors or bad coax between the antenna and the radio. (Wouldn't be the first time that a badly installed coax connector led to the tearing of hair. Trust me on this.)
2. You've got some unusual overwhelming source of radio noise in your car. Less likely, but still possible. I presume your car is running without the Check Engine light flickering madly. However, that's no guarantee. Bad grounds, missing grounds, screws missing on shields, ground wires that ought to be connected but aren't, or they're missing: Any of all of those can give you grief. By the by: If your car has this kind of problem, I'd half-guess that somebody listening to their radio when you drive past would notice! (Speaking as a ham radio bum, you always got those types with bad cars passing by, 100 yards away, when you're sitting there trying to receive some weak station transmitting from Ascension Island. And then they'd park in front of a red light, blowing your chance to talk to this far away guy, and you'd hear them accelerate away, buzzing as they went...)

Your average dealer knows how to deal pretty well with broken crankshafts and leaking hydraulic struts, since they can kind of see that stuff, but this radio junk leaves them gasping. I can easily believe that they'd say or (not quite) do anything to make you and your problem go away. Don't let them. Have them fire up whatever Prius they have on the lot to a radio station you know sounds lousy on their car. If your car sounds good just standing there, but goes blotto when you drive, make sure some guy goes with you and hears it. And don't accept, "They all do that." since, "they all do that" is a cop-out. Escalate it if needs be. I don't know this for certain, but I'd guess that Toyota's got regional people who do know their stuff and may even have the hand-held right kind of test equipment to check it.

I'm not kidding about the test equipment. Back in my summer hire days as an undergraduate, I worked on an HP (now Agilent) piece of test equipment called an 8903 Audio Analyzer. Really, really clean audio signal; put into the modulation input of an RF signal generator; feed generator into a dinky antenna next to System Under Test; recover the audio out of the radio, at the speakers; and feed back into the Audio Analyzer. Notch out the original audio signal and what remains is the distortion and garbage. We could give you SINAD and all sorts other nailed-to-the-wall specifications on a radio receiver. A bum radio naturally has lousy specs. And that was back in the mid-80's; by now, that relatively expensive junk is probably in the $1000 hand-held category, and I'd imagine any radio tester for a automotive company would have something like that handy. Just for stuff like this.

Good luck!

KBeck.

 

Hi Guys...Yep, in all fairness, I've yet to take it back to the dealer; car is only a couple weeks old, but I am getting close (I also have the "Rough ICE start/up" issue, occasionally)...Guess I'm concerned that when i take it in, they will automatically do the brake up/date & I'm not so sure I want it, especially if it does anything to reduce my fuel economy...I have no complaints about the brakes & I love my m.p.g....I guess you run out of luck sometime; I currently own four Toyota vehicles, all purchased new over the years & never once have had to take ANY back for ANY reason (I do all my own maint.)...
KBeck, I will try to get more detailed symptom info. on the radio reception issue, even though I don't think the "Phzzzzit" has any "Rhythm" to it...
Thanks

 

EVERYONE has the radio problem. But is it really a radio problem? Or is it the HU problem as a whole?

I have the HU unit with the NAV screen and etc.

What I have gathered is that it has nothing to do with the radio frequence, strenght etc. It is to do with the Prius itself. Something to do with the entire car electric wiring lume.

If you ever installed an HID unit on your Prius then the effect of the FM static significantly magnifies, to a point where you can no longer hear the same channel if you switch the HID lights on but can hear it again with hiss with you turn the lights off.

We thought that because this might be something to do with the FM unit in the HU not very good so I decided to buy myself the DAB raido (£500 pounds $900) and thought this will or might fix the issue. For many of you this might or will solve the hissing issue because DAB radio is either you have signal or none.

But for me with HID it didn't work because I can go on driving for a mile or two with the radio on with no signal at all with HID on.

So now my only option is to upgrade to Genuine Toyota LED pack to sort out my problem. But I think it will take them a while to figure out the problem and even when they figure it out I think they might not implement the fix because it will be an expensive one much more than then all their recalls so far.

So don't go out get bigger and longer attenas it won't work. And if you get a booster it will just boost the noise. It is either the car lume problem or the HU radio eletrical has compatible problem with the electric of the car. I think it is major.

 

I think this is a recall/warranty repair that Toyota does not want to do (or its supplier). The HU is not working properly and I think they are trying to find a cheap solution to fix it. Which is taking them a lot of time. I have complained to Customer Service already 3-4 months ago, and still they have no clue on how to fix it.
Again - all those feeling they have random non-FM static noise, should complain and raise the issue at Toyota Customer Service (and the dealer). The more, the better and a higher chance of a fix.
Please do it even if you listed to he iPod all the time and help fellow Prius Owners (still) listening to the radio.

 

In my usual obsessive manner, I've spent a lot of time (perhaps too much time) researching this. Ultimately, I figured out my problem and learned a lot that might be helpful to others.

The 2010 Prius does have an antenna amplifier built into the base of the antenna. It is not line powered as some have hypothesized, but receives power through a separate wire pair that runs from the antenna base through the wire harness to the 20 pin connector that appears behind the Prius radio and plugs into the Prius radios or via an adapter to an aftermarket radio.

If you have an aftermarket HU
If you have an aftermarket HU and you're using one of the adapters like the PAC TATO, etc., , they typically do not provide antenna amplifier power. And even if you're not using an adapter and wired up your own pigtail, it's still easy to overlook the requirement because it's often referenced as "power antenna" when the Prius doesn't have a motorized antenna. Pin 13 of the 20 pin connector attached to the car (not to the radio) is a beige colored wire. You need to connect +12V to this wire to power up the antenna amplifier. In my Prius, adding +12V to this beige wire instantly boosted the sensitivity of my JVC HU and cleared up the same "pfft" sounds that others have been experiencing.

If you have a Prius radio and have reception problems
I downloaded the attached document from Techinfo that offers troubleshooting steps for radio reception problems. Hope it helps someone.

 

So the OEM HUs should be hooked up correctly, yes? So why would so many people be having problems with the OEM units? Could it be that that wire is not powered? Next time I am in the dash I will have to check this out with my Pioneer HU.
Thanks for the research!

 

Spiderman, you would expect it to be hooked up correctly and all components properly working, but if your reception is poor, then something isn't. I would go through the troubleshooting steps or if your Prius is under warranty, print out the techinfo document and bring it to the dealer with a request to go through the steps. As someone else remarked, technicians are always good at doing a brake job or a tuneup but nailing the nuances of the A/V system can be tricky. I bet that's why Toyota has done the step 1, step 2, step 3, etc., process for testing.

 

I already pulled my OEM HU and replaced it with a Pioneer. The reception got a little better but still not great. I guess I need to check if that pin 13 is getting power I guess from you mentioned.

 

I have found something very intresting out of accident. Because I have DAB redio installed it amplies the problem.
One day I turned on my DAB radio just for fun (I havn't used my radio much since I got this car because I hate static noice in radio) and my wife opened the door. Suddenly radio loses signal.
I thought hang on thats weird. Then I realized the map lights was the cause. I recently changed my map lights to LEDs and as I was sitting in the car I switched on the map light, guess what, the radio losses signal.
With normal radio, when the map light is switched on i will get terrible noise but with DAB because it is so sensitive it has no signal at all. To me this is very strange
Just because a map light is turned on then the Radio loses signal?
something is terribly wrong with the HU electrical or some where some electrical is wired or designed wrong.

 

An up/date...Well I was wrong...I do get the static when the car is stopped; IF I stop it in the "Right" spot; then the "Phzzzzit" turns to "Steady" static; I can then move the car only a foot or so either forward or back & be in a "Clear Zone" with perfect reception....It's this " Into & Out/Of " that creates the "Phzzzzit" when in motion...FWIW

 

Aha! Tande, what you're hearing is, no kidding, called "Picket Fencing". In general, radio signals aren't all that steady, they fluctuate up and down as the car moves. This kind of thing is always present, but is made worse by two factors:

1. Reflections. A radio wave gets transmitted; part of the wave comes direct to you, another reflects off a building somewhere. When this occurs there will be places where the two fields cancel; roughly, a quarter wavelength away, they add to each other. The "cancel spots" are therefore roughly a half wavelength apart, although that varies mightily depending upon what the reflecting objects look like, etc.
2. Wavelength. In the middle of the FM band the "null" spots are about 50 feet apart. So, the faster you go, the more rapidly you'll hear the spots. At 1000 on your AM dial (That's 1 MHz), a half wavelength is almost a mile long; further, you're going to need something pretty big, in terms of wavelengths, to do the reflecting, so unless you live near mountains you probably won't hear it.

The "nulls" aren't usually that deep since it's unlikely that the reflected and direct waves are of exactly the same magnitude. But, if you've got a receiver that's not all that sensitive, those "pfft" noises can get pretty obnoxious.

Picket fence? Think about the sound you get when you run past a picket fence with a stick up against the fence.

Next: Your radio's got weak reception. A previous poster found a problem in his system - the 12V for the antenna amplifier was unplugged! The same poster put up a link to the troubleshooting guide for lousy reception, which is what you got.

Link: http://priuschat.com/forums/gen-iii...o-reception-in-2010-prius-17.html#post1101381


Hie ye to thy dealer and Make Waves. Big Ones. Beat them about the shoulders with Sticks until they Relent And Fix The Thing.

Good luck!

KBeck

 

KBeck, Thank you so much....I think you have described it to a "T"....I will have to take it from here....Wish me luck!...

 

Good luck!

And.. Don't be a stranger. Come on back and tell us what happened. Inquiring minds would like to know.

KBeck.

 

Probably a question that has been asked, but some of you guys have GOOD reception, right? My Prius, manufactured in late 2009 I believe, seems fine with radio reception. I don't listen to too many channels, but one FM channel I do listen to actually has better reception in the Prius as opposed to my Acura TSX. No pfft sounds either. I don't have NAV either, just the JBL radio system that comes in the Prius III.

 

Some state they have good reception - but it seems most are in good areas... There was also (from memory) a post where the radio was swapped, and it fixed the issue. There are also posts stating new deliveries are fine.

Bottom line, there are gobs of random data points, but it seems a consensus of people over the last 6 months with issues.

It does seem strange that issues are reported in stock, JBL, and NAV JBL. The only recourse is to report it, and hope they fix it. I love AM/FM, so it was an issue for me (before swapping out the radio)...

 

I've just bought (last week) a new Prius. The radio is completely unacceptable when listening to FM, in my view. Previously I'd owned a 2005 Prius, and the radio in that wasn't great, but the new car is far, far worse.

I drove a few hundred miles cross-country earlier this week and suffered some loss of reception for more than 30% of the journey. At times, the radio was completely unlistenable, due to the "chuff, chuff" sounds coming from some form of beat frequency interference.

I'm writing to Toyota today. If they don't fix it then I intend to declare the car as "not fit for purpose" and see where it goes.

As an avid FM radio listener the radio in this car is a very big disappointment to me.

Jeremy

 

OK, so I have had mine for about a week (IV...Solar Pack) and I noticed a slight weakness. How bad are we talking here? Audiophile bad or just kinda bad....

Thanks!!

 

Well...I can say only this; normally OEM radios serve my needs just fine & I currently have three other Toyota vehicles (which includes a gen. II 2005 Prius) with OEM radios that do just that...BUT, not so with my gen. III Prius...FWIW

 

OK. I've been thinking about this.

The problem is as follows: Some people are complaining about weak reception. Other people are saying that it seems OK. And, of course, there are those in the middle who think, "Geez - some people are complaining about weak reception! Maybe that noise I hear is that stuff!" and then go off to complain.

With egregious cases (local stations are gone) then it's an easy determination. But, for the rest of the world, it's hard to make a case one way or another because the judgment as to whether the radio is bad or not is based upon human senses. And, with those senses hooked up to the naturally-overexcited human brain, judgments become questionable.

There's a solution to the problem. It's called Test Equipment. It's not like there's not gear available that can nail receiver sensitivity, signal to noise ratios, and anything else one might care to mention. It's just that Mere Mortals (a) don't have access to the stuff and (b) wouldn't have a clue on how to use it if they did have it. (EE's, ET's, radio/TV repair techs, and ham radio operators excluded.)

What we need, I think, is a go/no-go test box. Said box should be:

1. Dead cheap with as few components as possible.
2. Easily constructed with parts from, if possible, the local Radio Shack and, failing that, the local radio/electronics supply store.

The idea here is that a local techie could build such a beast, attach it to a car, and find out if the car's radio is sensitive to a low-amplitude signal.

If the box is small enough it could be mailed around so people in remote, non-Radio Shack areas might be able to take a whack at the problem.

Next: What we want here is a box that emits somewhere in the FM radio band with a real low-level signal. It ought have 200 kHz deviation (standard for FM) with, say, 1000 Hz modulation. Further, there should be a switch so that a different FM frequency can be selected; this, so if the box's designed FM frequency is in local use, an alternate one can be picked.

I'm pretty sure that we don't want to set this thing up with a radiating antenna. For one thing, that would mean that the in-air radiation pattern would affect reception. I have this image of the box being moved back and forth in frustration.. For another, if this thing radiates, even low level, the FCC may become involved. They don't like unlicensed transmitters in the commercial spectrum.

Nope, probably the best thing would be to unscrew the antenna on the roof and screw this box in in its place. That would have the advantage of hopefully consistent results. There's the question of a ground. But let's leave that for later.

Next, signal levels. Well, the good thing is that at 100 MHz (FM band) there's not a heck of a lot of environmental background noise. In the AM band the radio noise from the atmosphere, far-away lightning strikes, and all that is much larger than any noise generated by the typical radio. I would say by the time one gets up to 100 MHz, unless one is mucking about with nitrogen-cooled radio front ends, the noise floor is set by the thermal and electronic noise of the components in the radio system. Comments on this? I do a fair amount of high frequency design, but I don't muck with radios, per se, much.

So, the general idea, to start, is to build such a box with a potentiometer attenuator. Connect the box to the antenna and a ground (there's a screw into the car metal on the antenna mount, right?) on a "working" Prius. Start off with the pot cranked to max amp, tune the car radio to the 1 kHz tone, then crank the pot down until the signal disappears. Crank the pot back up again until the tone can be barely heard above the background noise, then mark the dial.

At this point we're calibrated, sort of. Run said box through a dozen Priuses and see what they receive.. or don't.

Box would be battery powered, natch. For whatever reason I don't think the oscillator and modulator would be much of a problem. Building an attenuator that works and doesn't leak the (much stronger) oscillator signal through might be a bit tricky, though, and might require some metal-bending to make a decent shield. (Although I do have some copper sticky tape..) It should all fit into a relatively small Bud Box.

Cost of the box should be under $50 and would require some test equipment to verify operation. But I have that junk.

So: The above is a list of requirements. Any comments? This a good idea? Somebody want to add something or take something out? Come forward, Tin Men! (and women).

Ha. I can just see it now:

Customer: "But this box says my radio doesn't work!"
Service Adviser: "?!?"

KBeck

 

KBeck,...You're/The/Man...Right about now, "Toyota" could use you, BIG/TIME!..."Toyota", I can only hope you're listening!...ray: