ECU reset?

[BA9092]

Had my bench unlock done for my 2020 Supra last spring and I've been on MHD OTS flash since then. The car has been great! However, I went out of the country last week and my battery tender wasn't fully plugged in for some reason.

I tried starting the car but nothing happened. After a long night on the charger, the battery shows that it's fully charged, but I've got the "Drivetrain malfunction" message on my infotainment unit and there's a constant clicking sound coming from my ECU that sounds like an old clock. I've attached a small video below.

The only time it doesn't click is in diagnostic mode and after it's accessories are off (6 minutes after the last door closed.) I still can't pull any codes to see what's wrong since it can't communicate with the ECU.

I've seen some ECU resets in the BMW forums where you remove both negative and positive battery terminals, then touch them with one another to "reboot" the ECU. I haven't seen anything like it in the forums, so I'm afraid to try that.

Think I just need another bench unlock and start from scratch?

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[Tsuki8]

Apologies, dont have much to offer.

Have you tried removing both terminals from the battery? (Positive is prob good enough)
Maybe let it sit overnight for the car to drain?

All terminals on the ECU fully seated?

 

[Axix23]

your Supra died in a week of not driving?!!!

 

[razorlab]

All those symptoms are classic bad battery. Might show as charged but it could be damaged from going dead.

It going dead from just a week of no driving also points to it being on its last legs to begin with.

 

[BA9092]

Still troubleshooting.

1. Removed battery and had it checked. 12.7 volts and fully charged according to Autozone and Advanced Auto Parts.

2. Removed ECU and too it to the shop where they did the bench unlock. Still looks good.

3. Check all the fuses - rear passenger compartment in trunk as well as the passenger footwell. All are good. Even checked the 6 behind the DME connections under the passenger carpet!

 

[razorlab]

Still troubleshooting.

1. Removed battery and had it checked. 12.7 volts and fully charged according to Autozone and Advanced Auto Parts.

2. Removed ECU and too it to the shop where they did the bench unlock. Still looks good.

3. Check all the fuses - rear passenger compartment in trunk as well as the passenger footwell. All are good. Even checked the 6 behind the DME connections under the passenger carpet!

Did you try a different battery yet? I’m not a betting man but I bet that’s it

 

[kaj]

When lead acid batteries run to complete zero, they usually cannot recover. You will need a new battery.

 

[BA9092]

I'm going to pick this one up today and try it.

https://shop.advanceautoparts.com/p...for-high-electrical-demands-h9-agm/10866724-P

Any other recommendations?

I've only seen this one and the Antigravity one which is like $900 though.

 

[BA9092]

Nope. New battery didn't work.

All of my presets and Bimmercode settings are even still present with the battery disconnected overnight (both terminals) and a new battery today.

Is there no way to do a hard reset?

 

[baagel]

I'm just gonna ask again what others have suggested: are you sure the ECU connectors are 100% connected and secure? Tug on each connector on the harness side and make sure nothing comes loose.

 

[BA9092]

I'm just gonna ask again what others have suggested: are you sure the ECU connectors are 100% connected and secure? Tug on each connector on the harness side and make sure nothing comes loose.

Yup. They're all secure.

Are there any other fuses other than the two locations in the car?

 

[baagel]

There is a power distribution module next to where the ECU is inserted. From what I know there are some non-serviceable fuses inside of the module. It looks like this:
https://www.oemgenuineparts.com/oem-parts/toyota-control-module-82641waa01

 

[BA9092]

There is a power distribution module next to where the ECU is inserted. From what I know there are some non-serviceable fuses inside of the module. It looks like this:
https://www.oemgenuineparts.com/oem-parts/toyota-control-module-82641waa01

Yup! That 's it!

I removed it from its bracket and I can hear/feel the ticking from my original video coming from inside. It's completely sealed but it appears from some online searching that there are some standard automotive blade fuses in there. Not sure why they did that. Fml.

 

[Thepaulsurfer1]

TLDR: same happened to me, but bad BM3 flash caused Dme needing to be flashed back to stock then unlocked again (2021)

Not sure if this helps or not, but I had that same ticking on both original Dme and clone. After I got my unlocked Dme back from femto I tried flashing a BM3 OTS tune that failed, basically bricked my Dme and the clone because BM3 wouldn’t flash. After working with PTF for a week troubleshooting, they basically said some sort of incompatible software issue (weren’t specific, so I’m still suspect) and had flash back to my stock tune, relocking the dmes

my car also lives On a battery tender.

Headache to say the least, now my original is back with Louaye to FEMTO to be unlocked and waiting a bench unlock for the clone. Heading to ecutek faster than originally planned. Maybe this helps, maybe not.

 

[BA9092]

TLDR: same happened to me, but bad BM3 flash caused Dme needing to be flashed back to stock then unlocked again (2021)

Not sure if this helps or not, but I had that same ticking on both original Dme and clone. After I got my unlocked Dme back from femto I tried flashing a BM3 OTS tune that failed, basically bricked my Dme and the clone because BM3 wouldn’t flash. After working with PTF for a week troubleshooting, they basically said some sort of incompatible software issue (weren’t specific, so I’m still suspect) and had flash back to my stock tune, relocking the dmes

my car also lives On a battery tender.

Headache to say the least, now my original is back with Louaye to FEMTO to be unlocked and waiting a bench unlock for the clone. Heading to ecutek faster than originally planned. Maybe this helps, maybe not.

Good to know!

Yeah, I took my ECU to where I got my first bench unlock done and they said it looked fine when they hooked it up, so I'm guessing it's not bricked.

The ticking is definitely coming from this little guy - the integrated control module. I can hear it and feel it by holding it up and away from the bracket next to the ECU.

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