2007 Gs450h Hybrid Battery Cell Replacement For $50.

Great job! 

Proud of you- but I would not be so adventurous as you to explore so deeply. Way beyond my DIY abilities. 

My own 450 Hybrid came up with those scarey warning messages earlier this year. Worried the hell out of me. The local Lexus agent wanted about £150 just to use their analyser, but without any promise of a solution so I gave that a miss. Fortunately I was recommended to Hybrid Battery Solutions Ltd in Northampton.

He promptly analysed the problem, replaced the weak cells and restored the rest. The car seemed to be a lot perkier afterwards, and economy was consistently back over 40 mpg. Panic over and back to enjoying a fab car.

It should be noted that not all bad modules "pack of 6 cells" will show any outward signs of failure. In fact the great majority will have no signs on the outside of a failed cell within the module.

It has been known for the top to blow off modules if the internal pressure gets to high with the module continuing to work. This pressure is or should be regulated by a pressure relief valve under where the vent tube fits onto the module. If this valve sticks instead of the internal pressure being limited to 80 psi it can reach more than double that figure. 

Under no circumstances should a module be charged unless the sides are supported by thick timber boards clamped in a vice or "G" clamps. Failure to do this can result in the sides of the module blowing up like a balloon.

John