Gs450 won't start following flat battery

[ricky73]

Hi,

I recently flattened the Battery on my 2009 450 (40,000 miles) after the boot was left partly open. The AA came out charged the Battery so lights etc. were working, however the car still won't start. When the power button is pressed the display came on as usual however the engine won't start and error messages Check ECB and Check Hybrid System flash up. The recovery man tried a new 12v Battery but still no joy, for the record the 12v battery was replaced 11 months ago by a Lexus dealer as I had problems starting the car, they also ran a diagnostic with no problems noted. Next step will be to get it towed back to the dealer which will be a lot of hassle so any suggestions would be much appreciated.

Many Thanks,

Ricky 

 

[royoftherovers]

Roy, is the car under a Lexus Warranty ?

Regards

John

[Britprius]

1 minute ago, ricky73 said:

Hi,

I recently flattened the battery on my 2009 450 (40,000 miles) after the boot was left partly open. The AA came out charged the battery so lights etc. were working, however the car still won't start. When the power button is pressed the display came on as usual however the engine won't start and error messages Check ECB and Check Hybrid System flash up. The recovery man tried a new 12v battery but still no joy, for the record the 12v battery was replaced 11 months ago by a Lexus dealer as I had problems starting the car, they also ran a diagnostic with no problems noted. Next step will be to get it towed back to the dealer which will be a lot of hassle so any suggestions would be much appreciated.

Many Thanks,

Ricky 

 

Did you or the AA try to jump start the car before charging the Battery?

The 12 volt Battery does not actually start the engine in the normal way of other cars it just boots the computers and operates a few pumps. It is possible that the a jump start or charging the 12 volt Battery with the connections reversed has at minimum blown some expensive fuses or damaged some ECU's.

It is the high voltage Battery that is used to power one of the two electric motors in the transmission to turn the engine.

John 

[AmbroseJohn]

My 2008 started with no problem after I flattened the Battery.

The 12v battery's main function is to power the computers. The engine is started by the hybrid system, not a traditional starter motor, but that will only happen if the computer tells it to. I would normally recommend a reboot but as you've already removed the 12v Battery and refitted, it looking like a dealer job.

Try another reboot, with your fingers crossed.

Good luck and let us know the results

 

[Britprius]

Check for 12 volts at the large terminal in the fuse box under the bonnet. If a 12 volt supply is not there it is likely that the fuse at the 12 volt Battery + terminal has blown. This fuse is rated at from memory 150 amps. If you do not have a multi meter a 12 volt bulb connected from the fuse box terminal, and any part of the metal body or engine should light. 

John

[ricky73]

Firstly thanks for all your replies. The warranty would have run out in 2014, 5 years from date of registration.

I checked the car again tonight (not had a chance to look at the fuses) and the 12v Battery is almost flat again despite being fully recharged yesterday so It looks like a recovery tow to the dealers is the only option now. Should the recovery man have charged the high voltage Battery directly? Would that be worth trying when the recovery truck comes as it would be lot simpler driving to the dealers then towing out of an underground garage>

Thanks,

Ricky

[AmbroseJohn]

11 hours ago, ricky73 said:

Should the recovery man have charged the high voltage battery directly? Would that be worth trying when the recovery truck comes as it would be lot simpler driving to the dealers then towing out of an underground garage>

Thanks,

Ricky

I don't think this is possible and if it is, I doubt very much if the recovery driver would have the equipment to do it.

[Britprius]

It is most unlikely the HV Battery is at fault. The fact that you are getting warnings about the hybrid system suggests the problems are with the various ECU's or the 12 volt supply to them. It may or may not be the case with your car. 

Jump starting "a term not really relevant to hybrids" or charging a completely discharged 12 volt Battery is fraught with dangers from reverse polarity connection of the charger or jump leads. As I said in a previous post the 12 volt Battery does not start the car as with normal vehicles. It is there to start the computers, and it is then there job to check all the systems are correct for the engine to be started. The computers connect the HV Battery to the various systems including the 12 volt Battery charging that is done from the HV Battery the car having no alternator in the normal way other cars do. It also has no normal starter motor run from the 12 volt Battery.

A low 12 volt Battery does cause problems with the computers as signals returned to them from various sensors on the car are incorrectly interpreted, and false error messages are given on the displays, and the computers assuming problems that may not be real refuse to start the engine.

John.  

Edited January 4, 2017 by Britprius
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