High frequency sound in Hybrid while gas engine on at around 40mph

[Mrgoochio]

Are some of these sounds the noise that electric motors are supposed to have by law due to them being so quiet?

https://en.wikipedia.org/wiki/Electric_vehicle_warning_sounds

I‘m new here so It’s just a guess.

I very highly doubt it, the vehicle already makes audible noise in reverse and drive at slow speeds during fully electric mode through a speaker.

I scheduled an appointment on the 25th of the month with a local dealer.

I also noticed the noise is easily reproduced when enabling “L” and slowly accelerating (audible mostly from 20-40mph). Seems like the issue is mostly present in low gear and possibly transmission related from my observations so far. Before trying L I already noticed the issue is reproduced by slight acceleration (maybe 10% pedal pressure between 20-40mpg). Using L to hold the vehicle in lower gear in this speed range makes it easy to reproduce the issue.

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[st3v]

Are some of these sounds the noise that electric motors are supposed to have by law due to them being so quiet?

https://en.wikipedia.org/wiki/Electric_vehicle_warning_sounds

I‘m new here so It’s just a guess.

No, it is not related to those sounds.

 

[st3v]

@Mrgoochio My 2023 Maverick XLT Hybrid that was totaled had those sounds a lot more audible than my 2024. Still occurs in my 2024 but it is faint and doesn't bother me. I am not sure if anything can be done about it by your dealership unless Ford gets involved and accepts that this is an issue.

 

[Mrgoochio]

@Mrgoochio My 2023 Maverick XLT Hybrid that was totaled had those sounds a lot more audible than my 2024. Still occurs in my 2024 but it is faint and doesn't bother me. I am not sure if anything can be done about it by your dealership unless Ford gets involved and accepts that this is an issue.

That would be awful bc the sound is really audible. If I noticed it during my test drive (I took the truck almost immediately onto the highway where the vehicle doesn’t make the noise) I would have definitely passed on this truck. One poster earlier in the thread mentioned his transmission and my experience seems to indicate it may be related as well. I don’t know if ford did anything for him or if he just came to the conclusion it was his transmission though.

I’ve noticed @Ford Motor Company posting on various threads where people had issues, but anyone have experience with whether they are they doing anything to get issues resolved or just trying to keep track of issues that arise?

 

[st3v]

That would be awful bc the sound is really audible. If I noticed it during my test drive (I took the truck almost immediately onto the highway where the vehicle doesn’t make the noise) I would have definitely passed on this truck. One poster earlier in the thread mentioned his transmission and my experience seems to indicate it may be related as well. I don’t know if ford did anything for him or if he just came to the conclusion it was his transmission though.

I’ve noticed @Ford Motor Company posting on various threads where people had issues, but anyone have experience with whether they are they doing anything to get issues resolved or just trying to keep track of issues that arise?

That transmission issue may be something else. My 2023 had the noises from day one. Ford contacted me too, but they just coordinate you to talk to the dealer. Nothing special.

 

[Mrgoochio]

Update: drove it with an actual technician he claims he can’t hear it or only hears normal regenerative braking. I’m extremely frustrated because this high pitch frequency definitely isn’t normal and driving me absolutely nuts. No resolution and he had no suggestions. He did not acknowledge any audible high pitch frequency during the drive while I hear it clearly, separate from the electric/gas motors

 

[cohensmobile]

Bump

Just got a 24 XLT Hybrid two weeks ago and experiencing the same high pitch frequency when accelerating. Any updates diagnosing? I feel like more people would be talking about it if it was a normal sound. Will take it to a dealer at some point but afraid the same thing will happen to me as did @Mrgoochio with a tech unless I can ID or point to other ppl who had the problem as well.

Almost sounds like something isn’t grounded and causing some type of frequency feedback related to the acceleration electronics.

 

[EONR24]

Bump

Just got a 24 XLT Hybrid two weeks ago and experiencing the same high pitch frequency when accelerating. Any updates diagnosing? I feel like more people would be talking about it if it was a normal sound. Will take it to a dealer at some point but afraid the same thing will happen to me as did @Mrgoochio with a tech unless I can ID or point to other ppl who had the problem as well.

Almost sounds like something isn’t grounded and causing some type of frequency feedback related to the acceleration electronics.

Have you experienced this noise the entire time you've owned the vehicle? I know there is a fake noise that hybrids must generate by Law for pedestrian safety.

 

[EONR24]

The second digit of this coding below is 0 on ecoboost Mavericks and is 4 on hybrid Mavericks. Meaning AVAS is enabled on Hybrids. I wonder if this is the noise.

 

[CurtisB]

I've heard the noise. It's common in hybrids. Mine sounds like a siren (a very quiet sound) that goes away as the truck warms up. It's just the way this engine works.

 

[OneAlienBoi]

Bump

Just hit over 1k miles on the odo, problem unchanged.

My issue is most prominent between 20-40mph under light acceleration. I would estimate around 5% pedal pressure with slight modulation I can hear a distinct “EEeEeeE” sound. It sounds very similar to a test tone when doing a hearing test at the doctors office. Above 40mph the sound is pretty much inaudible either because of road noise or because I’m depressing the accelerator more than 5-10%. However city/neighborhood driving is super frustrating hearing constant beeps and prolonged beeeeeeeeeeeeeee sounds.

haven’t had a chance to schedule service yet but will do so when I can get some free time. I need this vehicle for my work commute

@Ford Motor Company any insights or information regarding this?

I know the sound you're talking about. I've found you only really notice it with the radio off. As others have stated, it's probably the sound of some of the hybrid components doing their thing. I've heard the maverick doesn't have a lot of sound deadening, so you hear everything.

It's just like one of those things, kind of like how when you put the maverick in reverse, it reacts more than when you put it into other gears.

 

[Scott Asheville]

The really good news is that you'll age out of hearing high frequency sounds.

 

[JohnCondren1933]

Bump

Just got a 24 XLT Hybrid two weeks ago and experiencing the same high pitch frequency when accelerating. Any updates diagnosing? I feel like more people would be talking about it if it was a normal sound. Will take it to a dealer at some point but afraid the same thing will happen to me as did @Mrgoochio with a tech unless I can ID or point to other ppl who had the problem as well.

Almost sounds like something isn’t grounded and causing some type of frequency feedback related to the acceleration electronics.

I kinda hear it too. But I also work with industrial 3 phase servo induction motors and you definitely get different & quite noticeable "whines" & humming that changes pitch as you ramp the speed up & down depending on on the load on the motor.

I believe these whines are related to the level of charging load or resistance induced on the generator at different motor-generator RPMs, the charging circuitry is probably optimized for quiet regenerative braking using the main electric motor as a generator, there is a smaller generator which the ICE engine turns, which generates the electricity that drives the main electric motor - but during descent or braking the main electric motor starts generating current when a charging load in induced on the windings

...the occasional high-pitched whine at lower speeds, now I think, is a stage in the powertrain where the ICE engine is rotation the (smaller) generator shaft which is generation the voltage to drive the (larger) motor-generator shaft to act like a motor to achieve a governed mph speed,
but any slight downhill or flat areas where the vehicle gets more interial load on the wheels than the PCM-governed wheelspeed rpm,
causes short intervals where both the small generator is generating voltage on the DC buss, but then the (larger) motor-generator shaft is ALSO generating voltage on the DC Buss, raising the voltage level higher than the PCM feedback loop expects from the generating/charging load its putting on the (smaller) generator.

Its a weird edge-case where the standard controller programming isn't optimized for:

Typically at low governed rpm wheelspeed, if the larger motor-gen begins regenerative braking rolling down a hill, it won't start generating enough extra voltage to upset the PCMs control feedback loop, has time to ramp down the generating load on the smaller generator shaft to compensate.

Then at higher speeds, when the larger motor-generator starts regen braking to stay at governed rpm, the PCM can fully disconnect the small generator load from the ICE engine before turning off the ICE engine, and induce the max battery charging current-load onto the larger motor-gen shaft.

But at wheelspeeds just above low 20-35mph the powertrain is maybe in this non-optimized state where any short intervals of unexpected regen braking (like unexpected intertia from a slight downhill or heavier load in the bed), the unanticipated generated voltage could be instantly higher than the PCM can quickly ramp down the charging load on the generator, but the PCM doesnt want to fully disconnect the charging load from the generator or make the ECU cut fuel to the ICE engine, because the main traction battery still needs to charge up, not enough charge to power the larger motor-gen on electricity alone.

That's my guess, induction motors under variable loads make some weird sounds.

Oh shit I just realized something, "variable loads", if we have loads in our hybrid beds over 100 lbs we should switch to "tow mode" and put the trailer weight as the weight of the load in our bed. The hybrid drive PCM doesn't really care if the load is in the bed or pulled in a trailer, its gonna modulate the acceleration & regenerative braking the same (if it has the 4000 lb towing package with trailer brake it will also try to modulate the trailer brakes, but for the 2000 lb model theres no difference).

I just realized I am driving around with 200ish lbs in the bed, so the hybrid drive is witnessing larger inertial loads from the unexpectedly heavier vehicle that its not expecting.

That's exactly where some of this high-pitched whine at lower rpm could be coming from -- and it does happen going up a grade.

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