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Discussion Starter #1
Morning -
My 2006 Highlander Hybrid is pulling these two codes: poaa6 & poa7a. I've read the descriptions for each and have an idea of what they tell me.

Has anyone else had these error codes?

If yes, how did you resolve them?

For those that are experienced at this, could you suggest steps I take to work on this?

Any help would be greatly appreciated!!

best,

Ron
 

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Failing inverter coolant pump. I think, first code is secondary to the second one, as safety measure. We had several hybrid owners with failing inverter pump.
You have two pumps. One is for coolant. One is for inverter. Look under the hood. See rectangular canister with pink coolant on the right hand side, next to radiator? That is your inverter coolant canister. It sits right atop of the inverter and hybrid synergy drive. Same coolant cools down motor generators, hence, having "transmission" code comes natural along.
There is not much you can do. Unless you look at empty canister? Then, possibly, simple refilll, but question is - what happened to coolant to start with. Otherwise, it's replacement.
 

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ukrkoz -

thanks for your insight. i will check it.

just curious, have you had any experience with the p0aa6 code for the h-battery isolation issue?

this all started after a few VERY cold days of winter weather when the car was parked outside.

ron
 

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Hmmm...This sounds like a possible 12V battery issue.... for 2006, it's pretty darn old, if it's OEM. 12V can cause various hybrid codes. Maybe start there?



High Voltage Isolation Fault (P0AA6)

This code is set when the BMS measures an isolation breakdown between the high voltage battery and the 12 volt system. A breakdown in isolation can be caused by ruptured or leaking cells, high voltage cabling insulation that has rubbed off and come into contact with low voltage systems, condensation, use of non-isolated equipment, other causes or by an intentionally non-isolated design




There is ton of that code discussion online for Prius.
 
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