TRD PRO ALTERNATOR FAILURE???

[johnandri]

My TRD Pro has around 6,000 miles, and the other day my dashboard suddenly lit up with several warnings — Drive-Start Control System, Engine, and Advanced Ultrasonic Detecting and Ranging System. Despite the alerts, the truck was still driving fine. I decided to have it towed to the dealer.

A few hours later, the dealer called and told me the alternator had failed. I haven’t seen many posts about alternator issues with these trucks, so I’m just wondering if anyone else has experienced the same problem?

The dealer stated it would take around 3 to 5 days for the part to be shipped out and repaired.

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[GMak621]

Better these things come up early and are taken care of by warrant. Probably just a defective unit

 

[Rubenc87]

Could that be a reason for the TRD Hybrid 12V batteries running on low voltage?

 

[tacorancher]

I think @TacoFreak should weigh in on this one. But if you have a 2025, I think it has a different / supplemental charging mechanism for the 12V battery.

 

[JayZap]

I think @TacoFreak should weigh in on this one. But if you have a 2025, I think it has a different / supplemental charging mechanism for the 12V battery.

I think it’s also important to note of you have the 4 aux package on the 25 year TH/PRO you have a different/supplementary 12 volt charging system

 

[Rubenc87]

Mine tested at 12.2V

 

[Yotota]

Based on my ownership, and purely IMO, the Denso alternators that Toyota uses aren't the "best of the best" compared to Bosch or even Motorcraft.

Every modern Yota I've had killed an alternator by the 120k-ish mile range. And it's not unheard of for them to occasionally die earlier.

It happens. No automaker is perfect, especially Toyota. I still think it's the best brand.

 

[TacoFreak]

I think @TacoFreak should weigh in on this one. But if you have a 2025, I think it has a different / supplemental charging mechanism for the 12V battery.

It now appears that hybrids all use a voltage converter to charge the 12 volt from the hybrid traction battery when the truck is on. At least some 2025 owners have 12 volts that sit at a low state of charge even with the alternator. So I don't think that the alternator charges the 12 volt, but is there to support the 4 AUX package. One dealer told an owner that even a resting state of charge of 11.8 volts is considered normal. The results of that are a shortened battery life and not much reserve for anything that uses power when the truck is turned off. That is why many hybrids won't even turn on if they sit for very long. I now carry a jump pack so I can know my truck will be able to start and run.

Mine tested at 12.2V

That's what mine sits at too, no matter how much I drive it. That didn't stop my dealer's service department from telling me both that it was normal and that I should drive it more to keep it charged. It would be better if their lies at least made sense. lol

 

[TacoFreak]

My TRD Pro has around 6,000 miles, and the other day my dashboard suddenly lit up with several warnings — Drive-Start Control System, Engine, and Advanced Ultrasonic Detecting and Ranging System. Despite the alerts, the truck was still driving fine. I decided to have it towed to the dealer.

Since the hybrids charge their 12 volts from the traction battery and also use that battery to start the engine a failed alternator should leave the trucks functional at least. You just wouldn't have the full AUX capacity until the alternator is replaced. Only hybrids with the 4 AUX package in model year 2025 even have alternators, which is probably why we haven't seen many failures.

 

[johnandri]

It now appears that hybrids all use a voltage converter to charge the 12 volt from the hybrid traction battery when the truck is on. At least some 2025 owners have 12 volts that sit at a low state of charge even with the alternator. So I don't think that the alternator charges the 12 volt, but is there to support the 4 AUX package. One dealer told an owner that even a resting state of charge of 11.8 volts is considered normal. The results of that are a shortened battery life and not much reserve for anything that uses power when the truck is turned off. That is why many hybrids won't even turn on if they sit for very long. I now carry a jump pack so I can know my truck will be able to start and run.

That's what mine sits at too, no matter how much I drive it. That didn't stop my dealer's service department from telling me both that it was normal and that I should drive it more to keep it charged. It would be better if their lies at least made sense. lol

My truck is not my primary vehicle, so sometimes it will sit a day or two before I run it, so hearing that is a bit troubling. The jump pack is a good idea though. I'll grab one for sure. I appreciate your input.

 

[TacoFreak]

My truck is not my primary vehicle, so sometimes it will sit a day or two before I run it, so hearing that is a bit troubling. The jump pack is a good idea though. I'll grab one for sure. I appreciate your input.

We have to share information because Toyota won't come clean on this stuff. That jump pack pretty much guarantees that my truck will start and the cost was worth the peace of mind it gives me.

 

[WKTJR1]

I guess that's one issue I won't have.

Seriously, my truck has a resting voltage of 11.8v. For the last couple of months, I've been driving my Lexus before the snow hits. The truck just sits all week, and I only use it to take trash to the dump. Never had an issue.

 

[TacoFreak]

I guess that's one issue I won't have.

Seriously, my truck has a resting voltage of 11.8v. For the last couple of months, I've been driving my Lexus before the snow hits. The truck just sits all week, and I only use it to take trash to the dump. Never had an issue.

Good point - if you don't have an alternator it won't ever fail. lol

As long as your truck will turn on it will most likely start. But my wife's Lexus BEV showed me that the 12 volt can get so low that the vehicle won't even turn on, and then you do have an issue.

 

[WKTJR1]

These trucks are always clicking, whirring, or making some kind of noise. No wonder the batteries go dead.

Just wait until they start putting AI in them. You know it’s coming. It'll be like having your own personal HAL 9000, and we all know how that turned out.

"Unlock the door, Hal."
"I'm sorry, Dave. I'm afraid I can't do that."

 

[ORHV]

My 24 OR hybrid has a resting voltage between 11.9 and 12.2 Had dealer check it, 12.13 and is “acceptable and normal, but should be charged.” Toyota hasn’t made a trickle/maintainer for the 4th gen so they got ‘funny’ about using anything that doesn’t have ‘Toyota’ stamped on it!
Sooo, how do we charge it? “Just drive it”

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