EDUCATE THE DETAILER

After finished working on a Highlander hybrid, I decided to take the car to have only the interior washed. I specifically told the detailer not to bother washing the engine, since oI won't be around to supervised him.

I got to my shop to continue other jobs, only to be called some hours later that the vehicle couldn't power ON(readied).

I rushed down to see what was happening, only to realized that each time I try to ready the car, it doesn't come on. It only readies itself when the hybrid system service plug, and the 12V battery are disconnected and plugged back(resets the system).

Drove the car to the shop, and scanned it, and retrieved a P0aa6 isolation fault(HV was leaking on to body ground of vehicle).

I already knew tedious troubleshooting this code was.

So I decided to work back on what could have caused the isolation problem.

I touched the floor carpet of the car, it was wet. That was when I realized the cause of the problem must have being moisture accumulation at one of the HV system components.

Removed the rugs, and saw pounded water at the contactor area(HV relay assembly).

Got some shop cloth, and dried it up, removed the contactor assembly, and disassembled the HV relays to dry them. Sprayed some electronic spray on the relays, and the frame cables, before assembling.

PS:
Very important to get your vehicle detailed at a facility that understand hybrid vehicles.

If you can't get any close by, you either do it yourself, or put the car wash guys through.

Always be sure to check the integrity of the water drain seal on your vehicle.

In some instances, a ruptured drain seal could cause water accumulation, thereby causing a P0aa6 problem.