Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

2008 Toyota Highlander Hybrid - AM radio static only in drive or reverse

AM Radio has severe static while in drive or reverse, noise stops when in park or neutral. Noise slightly increases in frequency with speed, but not dramatically. CVT transmission keeps engine RPMs somewhat constant so speed is not a direct correlation. I’m guessing it has a relationship to the electrical drive system or hybrid battery charging. Local dealer had no clue, other than to suggest the alternator.

1 Like

I think you’re on the right track. Something in the electric motor is causing static and it may even be an indication the motor is about to fail. Both times the alternator failed in my Corolla there was a noise in the radio. Find a good independent shop that knows hybrids or another Toyota dealer.

Controlling the speed of the vehicle may involve pulse modulation techniques. Waveform pulses can generate all kinds of interference to other things. I would think that the engineers have designed proper filtering into the design to eliminate interference issues. The first thing to check is the antenna ground to make sure it is bonded to ground well. A faulty antenna ground will let noise like this get into the signal. If that is okay then I would make sure the ground wire shielding of the vehicle is working okay.

I would be curious to see if a portable radio in the car also had static. If not, you might have a radio problem. If it does have static, then you might position the portable at different locations to see if you can discover a source.

1 Like

You said you do not get static when you are in Park. What if you rev it up in Park?

Any difference in static while moving with the gas engine on vs. off?

The fact that the radio noise only happened when the vehicle was “in gear” was what led me to suspect the interference was being caused by the electric motor.

But only if the gas engine isn’t running.

No difference when moving, whether gas engine running or not.

AFAIK the electric motor is always engaged. In fact, at low speeds and in reverse it’s the vehicle’s main source of power. After all, that’s how you get “regenerative braking.” Granted, it’s speculation on my part but I believe either the electric motor itself or something in the associated circuit is causing RF interference. When the vehicle is “in gear,” a circuit, a relay, something is energized whether the motor is running or not.

It’s a hybrid - can’t rev it up it park. Throttle does nothing in park or neutral.

I guess if I want to “rev” the system, I would need to put the car on jack stands. Then, the portable radio on AM might be used to find the source.

Thanks. That makes sense. Now, I just need to figure out if it is fixable bd/or if is going to lead to damage if not fixed. I don’t care about the radio, I care about the hybrid system.

Gas engine can be running or not, same static.

It is not a radio problem. Same static happens to a portable battery radio.

Can you now use the portable radio as a detector? Move the radio around and find out where the static is being generated.
This problem might be a simple as a bad capacitor in a circuit meant to filter noise.

I’ll consider the portable radio for use in trying to detect the source of the static – not too wild about crawling under the car while it’s running and in gear, but I’ll figure out something safe.

Duck tape your radio to a stick! I agree, don’t crawl.

What if it’s a problem with the car’s radio? It might not be anything wrong with the car.

Edit - never mind, missed the ‘happens with a portable’ post.

AM Radio , they still have that ? I thought everyone was using Satellite , FM or Ipod for music now.