Hybrid battery thumping

[Whitelight23]

Back in the spring I was experiencing a problem with my reverse brake assist. Every time I placed the truck in reverse, an alert would appear in the dash that reverse brake assist not operable. This began after my first attempt using the pro trailer assist. It went to the local Ford dealer multiple times, and Ford engineering got involved. They did some updates to the PCM or ECM and changed the rear camera. I'm not sure they ever actually fixed the problem, but the dash alert doesn't pop up anymore. What they did do is create an unusual occurrence in the truck.
I noticed shortly after the attempted repairs on the truck and the updates to the module(s), the truck started thumping while parked in the driveway. This noise would start after the truck had been parked and the engine shut off for several minutes. I started hearing a thump every minute or so, and the noise would go on for quite some time. I crawled under the truck and the noise appears to be coming from underneath the rear of the cab. As far as I can tell, the noise originates from the hybrid battery.
I recently took the truck into the dealer because I was losing coolant from the engine, not the hybrid battery coolant system. I had a mechanic come look at the truck's coolant because Ford said it was yellow and mine was orange/ pink looking. When looking at the engine coolant color, the truck began thumping. The mechanic had no idea what the noise was. So I set the truck up for service regarding the coolant issue and the thumping. They were unable to find a coolant leak and could not recreate the thumping. Go figure. I don't know if they actually started the truck, which the noise starts after shutting it off.
I just read an article about a 2023 F150 hybrid catching fire and I started thinking about this thumping problem. Could this noise be an indication of a larger problem? I've recorded the noise, but it can be difficult to hear the thumping with the background noise. The video is attached of a short clip and there is a faint thump at 3 and 12 seconds into it. I have a longer recording, but the file is too large to attach. Is anyone else with the PB experiencing this unusual noise? If so, has a dealer or Ford figured out the problem and fixed it? I do not want to be a statistic if the truck were to burn up on a long drive pulling an RV.

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[skiteton]

My 22 Lariat PB made the same sound. Mine came from the speakers (B&O Unleashed, 18-spk) inside and there was nothing I could do to stop it. I felt that whatever was causing the sound to come through the speakers after shutdown was depleting the battery and in turn, fed my many electrical gremlins.

Open up a door next time you hear it and see if it's coming from your speakers.

 

[Fox146]

I had the same thumping sound from my (unleashed) speakers as well. I happened to be in the garage while it was doing it. Took a bit to figure out where it was coming from. The subwoofer is mounted on the back cab wall. It started after a DSP module update I did . It only does it for the time the retained power is on then stops. I think it’s fixed now with another update but I really haven’t paid attention

 

[PB2021]

I have never heard a thump but definitely a ton of sounds from the vehicle after shutdown on our 21. Around the hybrid battery I can hear at time what sounds like a relay or small pump running for periods or time.

 

[Madd-Dog]

Mine does it as well. 2022 Powerboost. It has done it for a while and was doing it yesterday. My truck is pretty up to date with Forscan, but I hope they fix it soon. It is annoying at most at least. Fingers crossed. I agree it sounds like it comes from the speakers.

 

[Mosey]

OP, the change in coolant color is normal. The primary coolant loop seeing much higher temp cycles. The hybrid battery is also cooled/warmed by the primary coolant loop. The smaller coolant system is for cooling some of the high voltage system, but not the battery.

As for the coolant loss, have you looked at your exhaust heat exchanger?

 

[Ford Motor Company]

Back in the spring I was experiencing a problem with my reverse brake assist. Every time I placed the truck in reverse, an alert would appear in the dash that reverse brake assist not operable. This began after my first attempt using the pro trailer assist. It went to the local Ford dealer multiple times, and Ford engineering got involved. They did some updates to the PCM or ECM and changed the rear camera. I'm not sure they ever actually fixed the problem, but the dash alert doesn't pop up anymore. What they did do is create an unusual occurrence in the truck.
I noticed shortly after the attempted repairs on the truck and the updates to the module(s), the truck started thumping while parked in the driveway. This noise would start after the truck had been parked and the engine shut off for several minutes. I started hearing a thump every minute or so, and the noise would go on for quite some time. I crawled under the truck and the noise appears to be coming from underneath the rear of the cab. As far as I can tell, the noise originates from the hybrid battery.
I recently took the truck into the dealer because I was losing coolant from the engine, not the hybrid battery coolant system. I had a mechanic come look at the truck's coolant because Ford said it was yellow and mine was orange/ pink looking. When looking at the engine coolant color, the truck began thumping. The mechanic had no idea what the noise was. So I set the truck up for service regarding the coolant issue and the thumping. They were unable to find a coolant leak and could not recreate the thumping. Go figure. I don't know if they actually started the truck, which the noise starts after shutting it off.
I just read an article about a 2023 F150 hybrid catching fire and I started thinking about this thumping problem. Could this noise be an indication of a larger problem? I've recorded the noise, but it can be difficult to hear the thumping with the background noise. The video is attached of a short clip and there is a faint thump at 3 and 12 seconds into it. I have a longer recording, but the file is too large to attach. Is anyone else with the PB experiencing this unusual noise? If so, has a dealer or Ford figured out the problem and fixed it? I do not want to be a statistic if the truck were to burn up on a long drive pulling an RV.

Hey there. I would like to take a closer look at this on my end. To get things started, can you please send over a message with your VIN and the name/location of the Ford dealer you have been working with?

 

[dochawk]

I started hearing a thump every minute or so, and the noise would go on for quite some time.

I had that problem one day headed out to the desert in my Deville.

It eventually stopped. I looked back, and the trunk was open.

Always double-check when you wrap the body . . .



?

 

[HammaMan]

OP, the change in coolant color is normal. The primary coolant loop seeing much higher temp cycles. The hybrid battery is also cooled/warmed by the primary coolant loop. The smaller coolant system is for cooling some of the high voltage system, but not the battery.

Incorrect, there is no battery heating capability. The battery self-heats due to its C rate in that it charges and discharges at such a high rate it naturally heats up rather quickly. I've seen it jump 35 degrees in under a minute.

I have never heard a thump but definitely a ton of sounds from the vehicle after shutdown on our 21. Around the hybrid battery I can hear at time what sounds like a relay or small pump running for periods or time.

That's the evap system, working as intended.

@Whitelight23 see if it's the audio system doing it.

 

[Mosey]

Not even when it is well below zero?

Incorrect, there is no battery heating capability. The battery self-heats due to its C rate in that it charges and discharges at such a high rate it naturally heats up rather quickly. I've seen it jump 35 degrees in under a minute.

That's the evap system, working as intended.

@Whitelight23 see if it's the audio system doing it.

Not even when it is well below zero?

 

[HammaMan]

Not even when it is well below zero?

Not even when it is well below zero?

Correct, PBs have no way to heat their battery other than using it, which heats it rather quickly. At -40c the battery and truck will not function, at all.

 

[Mosey]

Thanks. I learned something new, and at my age that is a good thing.

 

[PB2021]

Correct, PBs have no way to heat their battery other than using it, which heats it rather quickly. At -40c the battery and truck will not function, at all.

Not sure I agree. I’ve driven mine in -40c and it functions quite well.

 

[Whitelight23]

I've had the truck since May of 2023 and during the 1st year of ownership, I never heard the noise. I would estimate I put 15,000 miles on it before I ever heard the noise, which started after the reverse brake assist service.

The next time I noticed the noise, I will pay closer attention to the speakers to see if they are the culprit. This would surprise me if it would be the cause of the problem because the noise will begin after it has sat 5,10,15 minutes or more with the truck off. I would think the retained power would be deleted after that amount of the passage of time. This is not like a relay causing the problem.

Regarding the coolant loss, I pressure tested the system and did not find any leaks at the heat exchanger. The coolant loss, coupled with the noise, is very disconcerting because in a few months I will be pulling a 7000# RV to Alaska and back.

 

[HammaMan]

Not sure I agree. I’ve driven mine in -40c and it functions quite well.

As soon as your batt thermometer reads it's -40c it will cease to function. It may have been -40c outside, but the batt itself was not.

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