I have Toyota Estima 2.4 petrol/electric hybrid 2010 (UK 60 reg) that I bought about 4 months ago. So far I had no problems with anything until a couple of days ago the HV battery stopped charging fully. It would charge much slower than usual up until about 70-75% and that's it.
There is an indicator of charging that goes from 1 to 5 bars. Normally it would show 1-2 bars during coasting and up to 5 bars when braking. As of yesterday, it's at most 1 at coasting and at most 2 during braking, even sharp braking. I can't think of anything that could be a trigger for this change, it just started happening when I started the car in the evening yesterday to go home from work.
I checked ECU for any fault codes - and the are none. What are the most likely reasons for this and how would I diagnose them?
Update: I've monitored it over last night and today and now see a bit more symptoms, but don't know what to attribute them to. Essentially, when the car is cold (i.e. started after a long period of being parked), charging works as I expect it to, with up to 5 bars on braking. After I've driven for about 30 minutes or so, the charging slows down significantly to at most 2 bars. This is regardless of the battery level - whether it's nearly empty or more than half full. This leads me to believe that the issue may be with inverter/converter block or some other part of the charging mechanism.