My Cybertruck will not start / power on

[Cyber1qhorsey]

I really don't want to delve on X-treme to find out how to land this bird without steer by wire, from highway speeds safely... A forum is needed! This is critical safety information...

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[Gigahorse]

I really don't want to delve on X-treme to find out how to land this bird without steer by wire, from highway speeds safely... A forum is needed! This is critical safety information...

Yea hoping we get the whole story when everything comes full circle.

 

[NoMoGas]

Yikes that is not nice.

If all the power is out, to get in you will need to use the frunk release to connect a 12V battery in the frunk to open the doors. I think its in the manual how to do it.

You might be suffering from the PCS critical failure or rear harness problem menitoned on other threads.

Are you sure you can’t connect to it or use the RFID key etc?

it is worth noting that there is no 12 V battery in a cyber truck. It’s a 48 V system, but does act the same.

 

[NoMoGas]

I really don't want to delve on X-treme to find out how to land this bird without steer by wire, from highway speeds safely... A forum is needed! This is critical safety information...

It doesn’t get that far. If it detects a failure, it does have a back up, but will not allow you to continue driving on it. You will have to pull over on the back up and call for service. Therefore, you are safe all the time.

 

[BannedByTMC]

Steering doesn't work when the car loses power, car brakes when you let off the accelerator

Without power to the motor inverter you won't get regen so the car should still coast somewhat. There will be some drag from the motor magnets.

 

[Crissa]

Any reference for details on the back up system for steer by wire?

Only 'there are redundant systems required'. I don't know anyone outside of Tesla knows exactly which is which.

We've seen reports of trucks on the road with a failure in one steering system become power-limited and sluggish but still controllable as the vehicle comes to a stop. The warnings on the screens said specifically that one steering system had a fault (though that might have been as the result of a daisy chain of things).

There's more than one power source, more than one steering system.

-Crissa

 

[JBee]

it is worth noting that there is no 12 V battery in a cyber truck. It’s a 48 V system, but does act the same.

It's also worth noting that you can "jump it" with a voltage between 9-16V. There's a built in DC-DC boost converter to charge the 48V to allow this.

The first thing you need to do is dig out the two cables behind the drivers side front fender and power them to pop the frunk. Then you need to remove the frunk rear liner and hook up the power source to charge it. Once you have connected that you can also unlock/open the doors.

 

[JBee]

Is this you OP?

Not good seems like this is happening too often now.

 

[JBee]

If it's steer by wire and the wire being an electric signal, at what point will it still steer when all power is lost? Not from a drained battery, but more from a component failure or in this case a non responsive CT?

We've all move cars when they lost power steering and power brakes, but they're still mechanical and just require more force. Is there anything to do if the power / computer just dies/ crashes, or does the truck also crash?

Semis with air brakes uses the air to release the brakes. Not apply them. But it also has reserve air in the tanks. Power brakes in a normal vehicle has some reserve vacuum to assist with the power brakes.. and power steering is not bad if you're rolling without power. More difficult if you're sitting still which would not be as much of an issue.

Rick

It seems if the PCS fails you not only lose steering but also the electric brake booster. So it won't stop in a hurry either.

Not good. They should actually use a air assisted brake booster for extra redundancy.

 

[DrPhyzx]

It seems if the PCS fails you not only lose steering but also the electric brake booster. So it won't stop in a hurry either.

Not good. They should actually use a air assisted brake booster for extra redundancy.

Yeah, with steer by wire, unlike vacuum boosted or electrically assisted brakes, there is obviously no physical linkage between the steering wheel and the steering rack, so the feedback at the wheel is totally synthetic and requires power. So, instead of becoming heavy, I would expect the steering wheel to go light when power is lost, which would be... uh... scary.

 

[Crissa]

The failure mode of an electronic input can be designed to either be light or heavy.

-Crissa

 

[DrPhyzx]

The failure mode of an electronic input can be designed to either be light or heavy.

-Crissa

The only way it can be heavy is if failure allows a friction brake (or lock) on the wheel to engage. You cannot power any kind of actuator to provide feedback without power. In any case, an assisted system can still turn the car (with high effort) but a by-wire system cannot. So either way, you have zero control with a system that is truly by wire - a gorilla can turn the steering wheel (or not if it is locked - also not a fun feeling) but the car cannot steer at all as a result.

 

[BannedByTMC]

Steering system needs a redundant and isolated power source which still functions if the main pack and 48V system fails since there is no physical connection between the steering wheel and rack. It does not seem to have that which seems like a major fail.

 

[Gigahorse]

Steering system needs a redundant and isolated power source which still functions if the main pack and 48V system fails since there is no physical connection between the steering wheel and rack. It does not seem to have that which seems like a major fail.

Yea I thought the steer by wire system had 3 redundancies built in so the odds of failure was like winning 3 lotteries back to back. If that is not the case and like you said these do not have that isolation backup this could be a serious issue that would require that system to be redesigned completely.

 

[Spacenoddle]

Yea I thought the steer by wire system had 3 redundancies built in so the odds of failure was like winning 3 lotteries back to back. If that is not the case and like you said these do not have that isolation backup this could be a serious issue that would require that system to be redesigned completely.

Not sure it need 3 redundancy system, 2 should be enough. the redundancy system only needs to bring you to a safe stop, no need to "continue driving fix later' type.

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