One of my most favorite unexpected features of my new 2023 130 is how it starts with no starter noise at all, it’s off and then it’s just on as if by magic. The reason I ask is I was toying around with the GAP tool changing a couple things and when I was done, the truck started like an ‘ordinary’ truck and the starter sound before it ran. Have no idea how that changed but I was horrified, lol. So far I think locking the car and going back in a while turned it back to silent. But how does it start silently in the first place? And how does it have the ability to do both? Perplexing.

 

You didn’t change anything in gap tool. Guessing you have P400, right?

The car has something called the BISG (belt integrated starter generator). When it uses that, under certain conditions (temperature, etc) you don’t hear the starter -- It just “fires up” under one rotation. I am unsure of what the parameters are (fuel pressure, ambient temperature, other inputs).

Sometimes when it’s been sitting for more than a while, or if the ECU’s reset -- it does rotate a few times, you certainly do get a few engine rotations, and when hear that it does sound more like a traditional starter as the engine turns over. You're hearing a traditional starter “sound” as the engine rotates over a few times. I think that’s what you heard here. EDIT: I did check parts diagrams, the P400 does have a traditional starter too that’s used for this purpose.

It’s a bit random on my car but the general rule is “when the engine is warm it starts on one rotation or less”, when the engine is cold I might take more than one.

I love how it just “womps” into being on. It’s very modern. Very cool. Other vehicles are only just now starting to get this tech. JLR was one of the first, I believe.

 

Hey, thanks a lot for the explanation of how it works, very interesting! I've only had the truck 3 weeks and it's started the same every time, until making some changes in car config. And that's definitely what caused it to go noisy, it did multiple times and stopped when I locked it and came back in a while. ECUs must have needed a reset or something. Also good to know it will do it at some point, now I won't think something's broken! Do you have a Trek too? Which one?

 

You may have just heard the regular starter.

I also have a P400 and after gap changes sometimes, and then randomly at other times the 12v regular starter has started the engine. It likely has to do with the 48v battery charge level or a bunch of other parameters. Typically when it’s just running it is the starter/generator that starts it. But there is also a regular old fashion starter bolted to the bellhousing as a backup, I’ve noticed it many a times while working on the car.