Highlander Hybrid Electrical Malfunction

Sounds like a software glitch affecting multiple systems. Have you tried disconnecting the battery to reset the ECU? This might clear temporary errors. Were there any recent software installations or maintenance before these issues?

I haven't tried a battery disconnect to reset the ECU and I'm hesitant without more info. No software installations or maintenance immediately preceded these issues. What are the potential risks of disconnecting the battery in a hybrid system?

I understand your concern. Disconnecting the battery can sometimes cause unintended consequences, especially in hybrid vehicles. Given the symptoms and the potential for programming issues, I'd suggest consulting a qualified technician who specializes in Toyota hybrids. They can properly diagnose and reprogram the control unit.

Following your recommendation, I took it to a certified Toyota technician. The diagnostic confirmed the issue was related to the control unit programming. The repair involved reprogramming the control unit, at a cost of 240€. The vehicle is now functioning normally. Thank you for your assistance.