Lexus RX400h Problems

Check Engine Light With Code P0AA6 on Lexus RX400h

Problem Description and Possible Solution

The Check Engine Light may illuminate with code P0AA6 stored for a hybrid battery isolation fault. Our technicians tell us this may be caused by water intrusion into the high voltage battery case. The water may be a result of cracking body seam dealer above the rear door strut mount. Any water leaks should be repaired and the high voltage battery system inspected for water damage and repaired and dried as necessary.

(9 people reported this problem)

Lexus RX400h Vehicles With This Problem

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Average mileage: 67,600 (54,000–80,000)
3 model years affected: 2006, 2007, 2008
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The Check Hybrid System warning came on while driving in the AM after a night of heavy rain. Would not start again after shutting off. Towed to dealer. Technicians tell us this may be caused by water intrusion into the high voltage battery case. The water may be a result of cracking body seam but did not say where. They want me to authorize them to find leak, fix leak, hope there is no mold, possibly replace mold ridden components, replace the high voltage battery system and so on. They are estimating costs of almost 10k. The car had previously been lightly hit, rear passenger bumper scraped and knocked it off holding clip, barely noticeable. I filed a claim with insurance co and am waiting to hear from appraiser who inspected yesterday. In the meantime I have found a hybrid specialist who has trained with a top Lexus hybrid engineer. He thinks it may not be as bad as I am being led to believe. If insurance claim fails it is going to the hybrid specialist. If you want to find out how the story ends let me know. I love the car and am freaking out. Dealer is letting me use a 2013 450h. Totally different then the 2008. It rocks. Makes the 08 feel like a Chevy.
Dealer said hybrid system would notbe covered under the 70K hybrid warantee becuase there was "water in the body" maybe from a leak somewhere in the frame. Estimated $650 just to start "tearing the car down" to look for the leak, then $5K+ to fix hybrid system. Looks like hybrid warantee is wortless if dealer can just claim that there was a water leak somewhere. This sucks.
My 2008 Lexus RX400H would not start today. The warning "Check Hybrid System" displayed on the dashboard after trying to start. I had the car towed to the dealer and just received the bad news! I was told that repairs will be very expensive as a result of cracks in the body letting water seap into the hybrid battery system. The dealer advised that I call my insurance company to file a claim.