Intermittent starting issues when accessory in 12 V socket

[SiliconeCatastrophe]

Hi all,

I have a 2014 Auris Touring Sports hybrid.

In April, I had the 12V Battery changed (by a Toyota dealership) and since then I've had... issues. From time to time (first occurrence 10 days after the Battery change), when I try to start it, I get a big read Battery symbol on the dash, then a warning of a fault on the P system, and then sometimes "check hybrid system" (attached video shows this). If I wait a few minutes and try again, the car starts fine and drives fine.

It's been back in to Toyota, of course, never plays up while they have it, but they did read off a logged fault code, "Lost contact with hybrid system". They advised changing a fuse (which was somewhat grubby), but the problem is still occuring. Now they want to change the ECU - for £1,100! I'm reluctant to dive in to that just yet (trying to get them to try a different 12V battery first!).

I have borrowed an OBD reader and confirmed that, when the fault occurs, it has code U0293 which is indeed a communication issue with the hybrid power train. But I've also managed to demonstrate now that this problem only occurs if my Dashcam is plugged into the 12V accessory port when I power on. This doesn't happen every time - my Dashcam has been permamently plugged in for about 5 years and the problem only started after the battery change and even now, the majority of the time the car starts fine even with the Dashcam plugged in. But for the last week, I've unplugged the dashcam when I stop the car, and only plugged it in again *after* starting. Car started every time. Went back to leaving the dash cam in and the second time I used the car... the error came back. NOTE: the dashcam isn't drawing power when the engine is off -- the power to the 12V socket is cut and the cam powers down (the chime you hear in that video just after I turn on is the dash cam powering up as the 12V socket activates).

My thinking is that having the dashcam plugged in is adding enough draw that, during the initial power-on surge, the new battery can't cope. And also that therefore I really don't need to sink £1,100 into a new ECU.

But I'm curious as to whether anyone else has seen this issue / has any insight / has experienced problems starting the car while the 12V accessory socket has something plugged in?

 

 

 

 

[flash22]

what fuse was changed? remove, clean and refit the Battery terminals check the 140a fuse on the side of the Battery with a magnifying glass

 

edit. looked up the full code

Lost Communication with Hybrid Vehicle Control System - this can be misleading as the actual cause is............................ Communication with power management control ECU is interrupted (1 trip detection logic).   I would unplug and plug the connectors to the power management control ECU which lives behind the glove box (black box with grey plugs) push button start or keyed ignition with push button ??

[SiliconeCatastrophe]

1 hour ago, flash22 said:

what fuse was changed? remove, clean and refit the battery terminals check the 140a fuse on the side of the battery with a magnifying glass

It was changed by the garage- they said it was the fuse on the ECU system (a 7.5A one IIRC), but I can't name it exactly (they said they have a diagnostic path to follow for the code).

 

Quote

I would unplug and plug the connectors to the power management control ECU which lives behind the glove box (black box with grey plugs) push button start or keyed ignition with push button ??

THanks, I'll look into that; it's a push button start, no key slot.

[solero]

Measure the current draw on your Dashcam. It may be going faulty and over-drawing current, dissipating the Battery.