Toyota Camry Failed Smog : Not Ready : No Check Engine Light

Our customer’s 1999 Toyota Camry CE 2.2L failed the biennial smog check inspection (category: OBD System Checks for being “Not Ready“). In most situations driving the vehicle for a week or two (streets & highway) will allow the vehicle to complete it’s self tests (readiness monitors) and become “Ready” so that it will pass the emission inspection.

Unfortunately, our customer drove almost 500 miles and still his Toyota was Not Ready for the following three monitors: Catalyst, Oxygen Sensor & Oxygen Sensor Heater.

He asked us to diagnose the problem. Although there was no check engine light illuminated, there as a pending diagnostic trouble code (DTC) stored in the vehicles computer: DTC P1155. P1155 is a manufacturer specific code relating to the Air/Fuel Ratio Sensor Heater Circuit.

Our technician diagnosed the air/fuel sensor and confirmed an open heater circuit. We replaced the a new Denso air/fuel sensor, cleared the fault code, and drove the vehicle.

In less than 20 miles of our drive cycle all three incomplete monitors (Catalyst, Oxygen Sensor & Oxygen Sensor Heater) became “Ready”. We re-tested the Camry and it passed.

Although in most “Not Ready” failed smog check situations, a vehicle can be driven to become “Ready” and pass a California smog inspection, repairs are sometimes necessary.

 

Check Engine Light: P0420 – Catalyst Efficiency Below Threshold Bank 1

HELP, my check engine light is on because of a P0420 fault code.

Catalytic-Converter-Filtration-ProcessThe P0420 code means that the vehicle’s computer has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). This does not necessarily mean that you have to replace the catalytic converter to fix the problem. Replacing the oxygen (O2) sensors may sometimes fix the code because the vehicle’s computer interprets data from the oxygen sensors to determine if the catalytic converter is working properly.

If the catalytic converter is in fact defective, you must replace it with either a factory (OEM) converter or a California Air Resource Board (CARB) approved aftermarket converter. Be sure that the aftermarket converter is the correct part by confirming:

  • Year/Make/Model/Engine Size
  • Test Group Name or Engine Family Number *
  • Manufacturer Part Number
  • Executive Order Number
  • Converter Location

* Exception: Federally certified vehicles (Non-California) may not have a matching Test Group/Engine Family number listed on the Aftermarket Catalytic Converter Database. So as long as all other criteria matches, the converter should be approved for the application.

If there are no options listed for your vehicle application on the Aftermarket Catalytic Converter Database, an OEM converter is required.

Many mechanic & muffler shops mistakenly install incorrect converters. If you are unsure, feel free to contact us with any questions.

** This information is accurate as of July 2016. For the most up-to-date rules and regulations, please contact the California Air Resource Board.