[Ssmithusasr]

My 2012 Lexus CT 200H throws a hybrid error warning it seems when the battery hybrid battery is very full from going a long distance downhill. When I bought the car it had a error warning showing the battery was bad, I checked it and it seemed okay and turned out There was a load of hair in the cooling fan of which I replaced with a new one and a battery voltage sensor in the hybrid battery pack. I replaced the sensor although there were still some high temperature darkening of one or two of the pins ports but it did seem to work well after I cleaned them. However on a trip home one night which was mostly downhill which fully charged the hybrid battery, almost home I switched to economy mode just to see how that would work with such a full battery and a after a minute or two I had the hybrid error warning. I reset it by disconnecting the battery and pulling the large plug from the fuse box and when I started the car the next morning hybrid error was gone. Basically 150 miles later the same thing happened with the exception I didn’t try the economy mode. I reset by just pulling the large grey wire from the fuse box again and let it sit overnight and again the hybrid error is gone and everything is working fine. Should have replaced the wire harness connected the voltage battery pack also which will be my next move? I was just wondering if anybody had experience with this, the engine seems to keep running when the battery pack is extremely full, I had read that that was intended to help drain the battery

 

[TobiasSing]

Are you using "B" mode for engine braking in any situation?

 

[Ssmithusasr]

I did use the b mode the first time, as I was trying coming down the long hill. I thought that may have been the issue so the next two times I didn’t touch it. It just did it again today, coming down a long hill The hybrid battery symbol on the dash went to completely full. At the bottom of the hill there was a traffic light, stopped for about a minute or two with the air conditioning running then as I started to takeoff I did it easily to see if it would use the battery power, worked fine for about 10 seconds then the hybrid error came in, I did notice the hybrid fan was blowing a faster level. Drove another 10 minutes to get home, reset the hybrid error and now running fine again.

 

[TobiasSing]

When you get the hybrid error, does it actually affect anything, or is it just a light on the dash? Does the car drive differently? I wonder if you could try doing a lot of driving without any downhill.

 

[Ssmithusasr]

When I get the warning, the electric drive ceases to work in the engine never stops running. The 20 pin connector that went into the Voltage sensor did have some signs of the heat, I was going to replace that next. I cleaned it and everything seem to work okay so I thought it might be okay. At this point everything seems to work until I get a long period of going downhill or the hybrid battery symbol gets fully charged to the top of the symbol. I live on an island in one side is higher than the other, so eventually when I go north I have to come back home and it’s downhill, that’s when I have an issue.

 

[Ssmithusasr]

 

[Ssmithusasr]

Yesterday I drove all day. I didn’t hit the areas with very long down hill drives but one or two times have down hill areas where the battery seemed to go to full charge.. These times starting from the traffic light i was heavier on the gas pedal so that that it wouldn’t rely solely on the battery to start moving and the hybrid error never came on. I also noticed I could hear the cooling fan running faster I would so didn’t hear before. It’s almost like the car programming is changing. I did notice this time then the engine and electric drive operating more together when accelerating and the hybrid cooling fan ran at higher speeds then it did before. It also seems that sometimes the hybrid battery level indicator would stay full longer while it was being used longer and then suddenly it would drop, but i think was more a function of the display not the actual battery status

 

[TobiasSing]

I don't suppose you have a dealer there that can find out exactly what the hybrid error code is? I wonder if there is some malfunction in a computer electronics that controls when the engine is used vs just the battery.