Guys.

2013 RX with just around 100k mi on the clock. Check AWS system warning light came on while driving on highway at 70-80mph. Light went off after restart but came back on return highway trip. Light never showed back up next day during local driving.

scanner A shows alternator charges at 13.2 volt when motor is spinning at 2000rpms but did not show aws fault.

scanner B showed AWS fault code c1299.

battery voltage is 12.89.

any ideas what this might be?

 

Google found this for me

https://www.engine-codes.com/c1299_lexus.html

It has few steps that you can take to eliminate.

Salim

 

thank you Salim. My tire sizes are the same, tire pressures are within norm otherwise it would trigger tpms light on the dash. I first suspected alternator going out because my reading is on the lower side at 13.2 volt at 2000 rpms. Looks like i wont be able to diagnose it myself and will have to take it to the shop.