Question

2003 Toyota highlander V6 2WD with engine code P0155 and the check engine light is on

Answer 1

Hi there,

The code is for a faulty O2 sensor. In this case it's sensor 1 on bank 2. This is the first O2 sensor in the exhaust on the radiator side of the engine. Normally mounted right in the exhaust manifold.

Answer 2

P0155 Toyota Code - O2 Sensor Heater Circuit Bank 2 Sensor 1
Read more: https://www.autocodes.com/p0155_toyota.html