2006 Toyota Sienna Q&A
2006 Toyota Sienna Question: 3.3L V6 throwing P0430 and P0157. Is the problem the CAT or the O2 sensor?
The van is running fine. The dealership first wanted to replace the exhaust manifold and the O2 sensor and now they want to replace the coverter. Im not doing anything until I am sure what the problem really is. COuld the bad converter be throwing the O2 code or is it a bad O2 probe throwing the converter code? - rwilli5
I'd focus on the rear O2 sensor. It's easy to check with a lab scope while creating reach/lean mixtures. Bad O2 sensor could cause low cat.converter efficiency. Zee - ZeeTech