2001 Toyota Sienna Repair Question
Mileage: 142,000 miles.
Toyota Sienna Sensor Problem
why do i get this check engine light and code when it passed the emissions test and what do you suggest i do to get rid of the light? .
Asked by (pending member)Answer
it can be a bunch of things, when you replaced the converter, it may have an air leak causing the converter to not heat up correctly. one or both of the O2 sensors may not be reading incorrectly as well.or it cold be other thingstoo.
you did not mention the possibility of a false reading, triggering the check engine light.
why should i assume anything is wrong if it passed the emissions test?
normally false readings occur with a bad battery and yu asked why does it light, i just gave you some thing why it would
What are the codes you are getting?
The EXACT codes are required.
icandoitdon, we'll need ALL of the codes. You'll need a quality code reader to read the soft codes as well as the hard codes. You should also check the wiring and connectors to the O2 sensor(s).
The error was diagnosed as P0420, "Catalyst system efficiency below threshold - bank 1." i replaced the catalytic converter and O2 oxygen sensor and it hasn't helped. wondering if the air flow sensor might be the problem....haven't replaced that yet.
what makes me suspicious is that the car passed the emissions test with good readings on everything even though the light was on due to thiis code (p0420).
any other thoughts would be appreciated...
Check the voltage to and from the O2 sensor(s) on Bank 1. Let us know what you get.