Weak FM radio reception in 2010 Prius?

I did a bit of testing while in the process of removing the LED's. Basically I tuned in to an FM station not near my house so reception was a bit fuzzy anyway before turning on any lights. As soon as I turned on the lights, I lost reception completely.

The first thing I noticed which was unexpected was that reception died as soon as I open the rear hatch. Must be due to reflection of the hatch near the aerial when open.

Then, removed rear licence plate LEDs, closed hatch and re-tested - Reception lost when lights turned on.

Removed Headlamp LED's - Retested - Problem fixed, no change when lights turned on

Re-Installed Licence Plate LEDs with Headlamps out - Reception Lost when lights turned on.

Tested with just one LED in any of the four exterior light sockets in isolation and the problem is re-introduced.

So I can conclude that the Headlamp parking lights and licence plate lights are on the same circuit or introduce the same problem in isolation or together. I replaced these with the standard lights again and no problem, radio reception is fine.

I then checked against the door lamps, map lights and interior light. Only marginal static was introduced with these LED's to the point that it was difficult to recreate a situation where it was noticeable enough to be a problem. Due to the fact that the internal lights are only really used when getting in and out of the car and when the radio is off, I will leave the LEDs in for internal use only.

Then re-tested with AM. No fault found under any circumstances. It is an FM problem only. Here in Australia FM stations are the only good ones so LED's going on ebay or good for anyone wanting interior only.

 

I just purchased a new 2010 Prius II, which was shrink wrapped when I got it on 5/8/2010. It was manufactured in April, 2010. I have the same poor FM reception problem as everyone else. My old 96/99 Camry had better reception. I live in the San Francisco bay area, which has good reception. I can clearly hear the background static noise in and out periodically. I also see the also "ST" icon on the radio LCD appear and disappear as I'm driving. I'm definitely going to complain to my dealer and Toyota about this.

 

I have the same problem.... I hope someone has told Toyota about this. You can call their hot line.

 

It shouldn't happen even with LEDs installed. My bro installed LEDs in his Prius Gen2 and it doesn't have any effect on his FM radio. Even if you strip out all LEDs and HIDs etc., you will still have FM radio problem with noice coming up to a tree and there are plenty of trees in the UK to make it a problem. LED and HIDs just ehances the problem but the problem is already there before anything is other than OEM.

 

My 2010 is now 3 weeks old from delivery to me. FM reception is terrible. That is really my only complaint about the car as I love everything else. XM Satellite reception is not much better. Although I like this car much better than my previous Mercedes that car's radio reception with a tiny antenna was significantly better.

I read about others replacing the antenna to no avail and the conclusion was wiring between the antenna and the head unit. On this one I am definitely going to toss a note into Toyota.

 

I'm afraid that changing from incandescent to aftermarket LED lights can easily generate additional interference on some types of lighting circuit.

This isn't to say that the FM radio doesn't already have a problem, that it does is well documented here and elsewhere. What it does mean is that if you add an unapproved electrical accessory, one that increases the radiated or conducted interference level, then you can't lay the blame wholly on Toyota if you have a bigger radio problem.

From your evidence, and that of the testing undertaken by GAM above, it seems fairly clear that fitting unapproved aftermarket LED lights increases the emissions from the car. It may well be that the emissions are increased to a level that makes the car non-compliant with the regulations. The fact that fitting LEDs to another car doesn't cause the same radio problem is neither here nor there; if the other car doesn't used switched mode light control then in all probability LEDs wouldn't cause a problem.

It seems very much as if the G3 Prius, in common with quite a lot of newer cars, uses a form of switched mode control for some of the lights, probably pulse width modulation to control things like interior light dimming, hence the interference problem when LEDs are fitted.

It may be possible to fit suppression components to your LEDs to stop, or at least reduce, the interference they create; it may be that some LED suppliers already have a fix. I don't know this for sure, but my guess is that this is a problem that is likely to occur more frequently as cars change the way they control their lighting circuits.

Jeremy

 

Actually I don't believe the LEDs are unapproved. The manual states to put in certain kind of bulb and I have but it just happens to be LEDs.

But even then the LEDs doesn't bother me much because they are not turned on while the car is moving 99.9% of the time anyway so I have radio.

But the fact that the radio has a problem and its nearly a year now and toyota has not yet done anything really upsets me.

 

I agree wholeheartedly that the radio is very poor, and am equally annoyed with the lack of response from Toyota.

The issue over the LEDs is that they aren't, technically, bulbs and are unlikely to have been through any sort of approval testing. LEDs are semiconductor junctions that are able to turn on and off pretty fast, certainly a few orders of magnitude faster than bulbs. It is probably this characteristic that creates a potential interference problem when they are driven by circuits that use switched mode control. The car will have been through some form of EMI certification testing with incandescent bulbs fitted, rather than LEDs, at least as far as the interior lights are concerned.

I pretty much convinced that the best way to fix the poor radio problem is to change it for a better one. Having discovered that a portable radio resting on the passenger seat has better FM reception than the standard radio has pretty much convinced me that I need to change it.

Jeremy

 

Lights in cars are often driven with PWM (Pulse Width Modulation), typically with 50% or less duty cycle, to increase their life time and control the brightness (esp. interior lighting). So PWM signals are already present in the car, any car.

Clearly there is a design flaw in the radio of the Prius, that is not affected or due to antenna length, operation of the vehicle and in some cases seriously affected by turning on/off lights and other types of operation.

It is important that everybody gets their voices heard at Toyota about this issue. We essentially all have radios with problems reproducing properly FM radio stations. Whether this is due to noise injected within the car (most likely) and not properly filtered out, faulty radio design (not likely since I have read people changing head unit to no benefit), wrong cable routing or else, we don't know clearly (and thanks to everybody here to help and try to find a solution).

What I want is a radio that works, I don't care what needs to be fixed - Toyota has to fix it. We need to increase the pressure on them to at least acknowledge there is an issue. I didn't get them here in Germany to openly admit it. They only said they have "no solutions/fix for my problem".

We spend several thousand $$$/€€€, we want a fully working car when delivered.

I expect Toyota to do something about it. Otherwise I could have bought some second class car from another manufacturer. Apparently they are looking into this, at least from what reported to me from the dealer, and it has been notified all the way up to Toyota Japan. But that no solution has yet been found, offered, after so many months, makes me believe they are not really working on it.

Radio technology and EMI reduction can be not easy, but not impossible. Likely the solution has been found and deemed very expensive for already built cars. But it appears that also those who have recently received a car, still have the same issue.

Again, to me is not bad reception, but noise when reproducing an FM radio signal. The noise I hear is not radio noise, but EMI noise injected on the signal. I have been hearing radio since 25 years, I know the difference. The fact also that is not there when the car is not moving is another indication. FM radio noise can be heard also when standing still, EMI, especially in the Prius, is likely pretty high when currents are traversing the car up and down when driving. The highest noise source is likely the low/high voltage converter. If the design is faulty, it can pick up also other things, like PWM from lights (LEDs or bulbs is the same; LEDs are PWM controlled as well, even the brake lights we all have, are PWM controlled, and pressing the brake, lighting up the LEDs, does not induce noise, at least in my Prius).

My only suggestion, is that everybody having a problem, should contact Toyota directly, as well as their dealer. And tell other Toyota Prius 3rd gen owners to do a check on their radio, listen carefully and report to Toyota if noise is heard. I hope this gets closure, because the car is otherwise "perfect", at least for me. It is a shame that its image is ruined by such a thing (linked to 19th century technology, nonetheless!)

 

With respect, PWM of LEDs is definitely NOT the same as PWM of incandescent bulbs, due to the intrinsic difference in the way that LEDs respond to a fast pulse. This is why switching from incandescent bulbs to LEDs can make EMI worse - the LEDs switch very much faster, which in turn generates fast edges on the wiring and it's these fast edges that most probably generate some of the high frequency noise which interferes with DAB radio. I've not heard of significant interference on FM from LEDs, as far as I know it's only badly affecting DAB, which is very prone to interference anyway.

Also, PWM control of lighting is relatively new, for example my last car (a 2006 model) didn't use it. It's wrong to state that "PWM signals are already present in the car, any car" because they probably aren't present in a lot of cars.

Certainly the FM radio is very poor, but it's not wholly an EMI problem. I've done a fair bit of testing on my car and there is some EMI present, but not enough to cause a good radio problems. I can even run a portable FM radio inside my car and get better reception than from the built in unit! This tells me that the radio and its installation is the main problem, although I'm certain that it's exacerbated by the relatively noisy RF environment in the car.

The one thing that I've pinned down for sure is that the motion sensitive noise is due to the physical motion of the car, in other words its multipath, not EMI. This again indicates that the radio is primarily at fault, although to be honest I can't rule out some form of complex interaction between an interfering signal from the car and the wanted signal.

I've contacted Toyota and I know that the local dealers are fully aware of the problem, so it really is a matter of continuing to push them to do something about it.

Jeremy

 

"I can even run a portable FM radio inside my car and get better reception than from the built in unit!"

There you go Toyota. Now get to work on a fix for all of us! Considering the premium I paid for the "NAV" package, the FM radio should be capable of decent reception and be relatively noise-free.

(I have no after market lighting components installed; my car is of 100% factory configuration)

 

Funny thing. I noticed that the local college radio station (300 W, about 10 miles away, more or less line-of-sight) comes in perfectly, while all the commercial stations distort. I thought "what if the problem is really front-end overloading?"

So I unscrewed the antenna. Absolutely no change.

Not sure what to think about that.

 

I have my Prius for just a week. The FM radio reception is not nearly as good as on my previous car, a Ford Focus 2010 wagon.

 

Jeremy, that's my conclusion too - multipath. I did some digging around and found there's very little easy-to-unearth info about the II's radio, but, I did see at least one place where it was described as having dual diversity capability. There is also the fact that there are two FM antennas on the car: the integrated unit on top (XM/FM) and the horizontally polarized wire-on-glass antenna at the top of the back window. I suspect the problem is that the diversity receiver is simply a bad design, not well matched to the dual antennas, and/or just unable to operate properly in dual diversity mode with those antennas. It's actually worse than a "normal" single diversity FM receiver unit.

Been thinking about just getting a new head unit, but I mostly listen to my iPod/iPhone, rather than the awful local FM stations, anyway.

 

I don't think the receiver has 2 antennas. There is only one RF cable to the unit, even as the receiver has 2 RF inputs. There are maybe differences between US and EU versions, as the US model has a standard DIN RF antenna input.

 

Anyone found a fix yet?

 

I'm at 3,000 miles and according to the dealer ready for my 1st service.
I will ask about this vexing issue and report back at that time what the dealer says. I'm not holding my breath. Maybe they'll pay for the satellite radio subscription as a "make good." (sure)

 

I am less than 20 miles from the FM station that I use and lose reception. How do I write Toyota about the problem, email or usps mail if so can you list your method of contact.

 

I have a 2005 Prius and a 2010. Both JBL. The CD's sound a bit better in the new car, but the FM radio is better in the old.

 

I just bought a new prius yesterday. Everything seems real cool, except the radio reception sucks. I notice the antenna on the roof just has a white plastic piece screwed in. Is that the antenna or am i missing something? I do not have XM or anything like that. Just a basic Prius II 2010. Thanks, Ray