Prius AM Radio

Please provide more info. You say the entire radio unit has been replaced already? It still does it? Then you're looking at a problem with the power supply to the unit or the antenna being wonky. If noise was entering the system somewhere the FM would work normally cause FM radio can reject noise.

Does anybody know where the AM antenna would be or whether it uses a ferrite core coil antenna inside the head unit? The FM antenna is the little beesting on the roof. The AM antenna should be a long loop of wire.

What does the static sound like? Constant hiss/swoosh = weak signal
Clicking or ticking = electrical noise/spark ignition
Buzzing = interference from electrical wires 60/50Hz hum
Hum that changes in pitch as you drive/brake = Inverter switching noise

Perhaps try a filter on the power supply to the radio head unit. If the head unit has an AM antenna input, try sticking a long wire in there and see if you're reception picks up.

 

Also check:

Soultek.com: Toyota Prius hybrid car radio problems?

It looks like a common problem.

 

It is certainly not normal. My final word:

Something isn't grounded to the chassis somewhere. This could be hard to find.

 

If under warrantee, go to techs at other dealers to get it fixed. I think the AM and FM antenna should be the same peice on the back of the roof. Maybe the shield on outside of antenna cable is not connected properly. I don't think I have listened to my AM radio for more than a couple seconds at a time when going through the modes to get from FM to CD or back. I think I better listen to it for an exended time and make sure it is working ok.

 

You may or may not be willing to chase down a bad ground somewhere in the system, but when the Prius AM radio is working correctly it is pretty darn good.

I have done a lot of AM DXing to pass the time on late night drives. The antenna is indeed the stick on the roof. The shielding and isolation are indeed impressive, because any other HF radio in there will only hear the Prius' electrical system, up to about 26 MhZ.

 

I agree, I listen to AM all the time and the sound on my 2006 is as good as AM gets. The only buzzing I get is when I drive under power lines. AMs' inability to reject noise is why we switched to FM in the first place. Perhaps it's time for digital AM radio to take off.

 

Sometime, when you're at the dealership, why not park beside another Prius for which the service department would have access to the keys. Ask them to tune both your radio and the other Prius' radio to the same AM station. See if both have the same interferences.

If not, tell them to figure out the problem and fix your radio.

 

Good idea. Do that. Compare it to something you KNOW works. Then they can't explain it away as being solar flares or some other sh!t.

 

Don, I had the same problem and have found a solution. My dealer replaced the radio, and the antenna and tightened all the grounds. None of this did any good. He then told me that Toyota did not know how to fix the problem.

I looked in my warranty manual and found a telephone number to call and make complaints. The first time , they referred me back to the same dealer and he told me that this is the way it was and that many Prius's had the problem and they did not know how to fix it.

The 2nd time I complained, they set me up with the same dealer but this time they sent a tech specialist and he spent the whole day re torquing the grounds and installing extra insulation in the antenna. This did the trick, I now have excellent AM reception and my faith in Toyota has been restored. The tech came from another state and even though I was out of warranty , it cost me zero for the problem was never fixed during the first 36K.

 

I tend to suspect that the "extra insulation in the antenna" is our clue. The coaxial cable from the roof stick to the receiver is probably good enough quality for most cars, with quieter RF fields. Good enough in most Prius. But if yours happens to be built with a chunk of cable with not quite enough shielding, No amount of radio box replacements will help on AM.

It would be great if the next AM problem Prius gets its antenna cable replaced with high quality coax as a first step.

I don't believe that vehicle mfrs. buy miles of the most expensive coax that they can find...

 

Speaking of radios

CD CD DX

 

OK, here is the REAL deal. The Prius, due to all of the computerized functionality and voltage converters involved in the hybrid drive, generates TONS of RF interference that covers up the broadcast stations signals. These "signals" change as the state of the car changes, acceleration, break application etc. Older non-hybrid cars also created noise (especially the ignition system and alternator), but not to the same degree. Also, these RF noise sources were not "moving targets" as much and standard noise reduction techniques were developed to deal with this, especially for CB and Ham radio operators.

There has been some attempt to quiet down the Prius, but it is a daunting task as shielding all the wires, computer boxes and inverters is not for the faint hearted. So it's just a fact of life that radio reception (AM, FM, CB and Amateur radio alike) will not be as good in current technology Hybrids like the Prius. The dealers weren't (for once, smile) BS'ing, Prius' just do this! BTW, as non-hybids became more computerized thay have become more difficult from a radio reception standpoint as a general rule...

 

Nevertheless, one in good repair does sound pretty good. There's just some flaw in the OPs car that no one has found yet. This is what warranties are for: the seller has to satisfy the buyer. Keep at them until they get it right.

 

After 4 years of great AM reception, static is suddenly a major problem on AM only.

Until last week I never noticed a problem with my AM reception (unless I was in a parking garage). Since then AM reception is very, very variable. Static seems to increase with engine speed and is very bad at night on the freeway.

I checked my antenna and it seems a little loose and I tried tightening it but that didn't really do the trick. Any suggestions or recommendations?

 

I recall a post on the yahoo Prius_Techincal_Stuff group from an amateur radio operator who had identified and cured several RF hot spots in his Prius. Can't find it by searching right now though. Maybe someone else will have better luck.