2006 Tacoma Radio Noise AM Band

I have a 2006 Access Cab Tacoma (2WD, Standard Transmission, I4 motor) that I purchased new 14 years ago. It now has 135,000 miles on it and drives fine.

However, when driving with the radio ON and listening to my favorite AM radio station (WHAM in Rochester NY at 1180 KHz) a fairly constant and annoying whine is there along with the programming. I get it at home where we are 20 miles as the crow flies from the transmitter and it gets worse as I get further away.

If I sit in my parked truck at home with the key in the ignition switch and move it to the ON position, which illuminates all the dash lights, and turn the radio ON at 1180, the whine is there along with the programming. I don’t have to START the motor.

If I move the switch to ACC and leave the radio ON, the whine continues for just about 60 seconds and then goes away. The programming is still there and sounds fine but the whine is gone. This is very repeatable.

I’ve tried it with a portable battery powered radio in the truck with me and the whine is there while it is on the truck radio. The whine goes away too at the same time as the truck radio 60 seconds after I turn the switch to ACC.

So, it appears to be a radiated noise and picked up on the antenna and not a conducted noise on the 12 volt power input.

I haven’t heard this noise on any other AM station. I’ve tried a couple. And it won’t be on the FM band which is pretty insensitive to radio noise, ie, lightning, etc.

Any thoughts on this phenomenon? I’m almost getting used to it but it sure is annoying.

Thanks for any comments.

Jolly

 

Look for bad grounds. On, near the ECU, antenna base, radio I believe there's a antenna wire junction begging the passenger side A pillar trim s well

I'm thinking the whine goes away after residual voltages are dissipated from everything else shutting down.

 

Hi Larzzz,

Thanks for your thoughts.

I did look for bad grounds, loose wires, terminations, etc. as best I could way back when. I'm sure some of the critical ones are pretty much buried behind the dash. It might be time to try again.

I think the timing of the instantaneous whine going away is related to a relay or something similar dropping out as when the headlights turn off if you leave them on.

Weird whatever the cause.