Moved to the Highlander Hybrid forum so a larger body of members can help you out, but I left a redirect in the 1st Gen forum.

 

There are 24 P0A7A codes becuase of the various sufficis.
They all relay to "generator inverter performance".
Also, you can not jump start traction/hybrid battery. Only dealer can do this.
You can jump 12V battery that's about it.
You need to tow car to dealer to fully charge traction battery and have 12V properly tested, as it's deep cycle battery and can NOT be tested the usual way. I was actually standing next to battery tester at O'reilley's and it had warning sticker on it - for conventional batteries only!

 

Thank you for your response. Since I posted I checked the Hybrid battery and it is at 300VDC so the problem is likely with the inverter/converter. Looking at used ones and was wondering does any one know which ones work with the
2006 Highlander AWD ? g92a0-48010 seems to have been replaced by
G92A0-48090 . And is there a difference in the one for the 4wd vs. the AWD ?

 

First have the 12V battery tested and/or replaced before you go down the road of replacing the inverter. That battery may or may not be a deep-cycle type battery. A bad 12V battery can confuse the computer and make it think there are problems with the hybrid system when there really isn't.

 

Thank you for your help. The 12v aux battery was charged and checked . No load 12.4Vdc with the ign on 11.7V . Had a charger with a 200A jump start option connected same results. Also cleared error codes and checked voltage at DTC port, fault codes return as soon as I try to start the car.

If this helps with the ign in the on position all accessories seem to work. Windows, moon roof, AC,lights, wipers etc. etc all work.

 

You really need to - not that it does matter in the grand schema of what's going on - to find out if your battery is OEM deep cycle Panasonic or not. Or, any deep cycle. Once again, DC battery can not be tested with regular means, it requires special equipment and protocol. Look up deep cycle battery test.
Also, 11.7V is boarder line low voltage for 12V battery. Voltage at 11.7 and below indicates bad battery.
Do you have navigation system? If yes, turn car off, press and hold Info button on nav, turn system on and start flipping lights switch On/Off rapidly, so that lights come up/turn off. On mine takes about 5 flips like this then Diagnostics Menu appears on nav screen. You can navigate to a lot of interesting info from there.
I join the choir - you will not avoid dealer. Self diagnosing and tossing expensive parts at it is almost destined to end in more and more expense. Though you appear at least to be handy with multimeter, so all the best and keep posted.

 

All of the accessories are working off of the 12V system, which is being supplied by the 12V battery. If the car starts up like it is supposed, a set of relays click over and connect the high-voltage traction battery to the inverter/converter, which then takes over supplying the 12V system. The fact that you see 0 on the hybrid battery meter indicates that the traction battery is not being connected to the system.

Clearly there is something wrong with the inverter/high-voltage system. My advice is to take it to Toyota or a shop that is familiar with hybrids for a more detailed look at the problem. There's a remote possibility that it's a winding issue in MG1 causing the problem. There's also a remote possibility depending upon when and where your friend bought the car that it might be covered under a TSB or as a warranty issue.

 

Just an update. Replaced the inverter with a used one for $466.00 and about five hrs my labor. The Highlander is running just fine now.

Thank for all the help.

 

That's great to hear. And very impressive that you were able to fix it for fairly cheap and just 5 hours of your time.

 

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