CONDITION: A vehicle owner living in Portland, Oregon performs a DIY maintenance on his 4 cylinder Camry, including spark plugs and universal oxygen sensors. After the repair the check engine light was illuminated. The vehicle was then driven to a professional repair facility. The service technician defined the check engine light as a Diagnostic Trouble Code (DTC) P0135 (O2 sensor heater circuit bank 1 sensor 1) with his scan tool.
CAUSE: Repair shop is located in Portland, Oregon; however this particular Camry is equipped with California emissions. An oxygen sensor, designed for non-California emissions vehicles was installed rather than the required air fuel ratio sensor.
CORRECTION: The recently installed oxygen sensor was removed and the proper air fuel ratio sensor was installed on the vehicle. The repair switched off the check engine light.
NOTE: All DENSO air fuel ratio sensors use a 9 in the fourth digit of the part number (i.e. 234-9xxx).
*May also be seen in various models which have similar system configurations (e.g. California vs. non-California models; Ultra Low Emissions Vehicle/ULEV vs. standard models).