yasir

Hello, Just wanted to post an update. I believe the problem is now solved. Based on mann777's suggestion, I ended up replacing both the upstream (Air / Fuel Ratio) and downstream (Heated Oxygen) sensors on the right (Passenger) side. I had a chance to finally do the work in the first week of May. Now, a month on and two tanks of gas (~600 miles), the MIL light has not come back on. Total cost to replace these sensors was $450. Original Toyota Parts and do-it-yourself labor. As an aside, the dealer obviously misdiagnosed the problem. On the written quotation they gave me, it stated that the rear right side catalytic converter exhaust pipe needed to be changed, with no mention of replacing the sensors. Plus, the two sensors that I replaced, measure the efficiency of the 3-Way Catalytic Converter which is a one piece unit welded to the end of the right side exhaust header. These trucks have four catalytic converters. Two on each side. One 3-Way Cat in each header and the Secondary Cat in the middle Y-Pipe section on each side. So, not sure how replacing this secondary converter, which is not monitored by any sensor, would have solved the problem according to the dealer. Anyway, Thanks mann777 for the help. Yasir

Hi, Thanks for the response. That sounds reasonable to me. Yasir

Hello, I was hoping someone could confirm an estimate I got from the dealer. I recently purchased a 2005 Lexus GX470 with 83K miles. I got a Check Engine Light (and VSC & TRAC lights) this past week. I took it to the dealer for other items (new tires) and they found that the right side (passenger side) catalytic converter / exhaust pipe has a leak. The error code given is: P0430 - Catalyst System Efficiency Below Threshold - Bank 2. I confirmed this with a scan tool. This is the only code that shows up. The dealer recommends replacing the front right side exhaust pipe with catalytic converter (Part #17410-50450). Needless to say, they want quite a bit to do this, approximately $2,200.00. If this truly is the problem, then could the existing pipe / converter be patched or welded? I suppose if it is something internal then perhaps not. Also, I did some research and found the part online. A Genuine Toyota Replacement right side exhaust pipe & converter costs a little less than what the dealer is charging; $830.00 (http://bit.ly/cEaUec). A direct bolt on aftermarket part made by 'Benchmark' costs $285.00 (http://bit.ly/byvnVD). I'm handy with a wrench and have some experience with exhaust work on some older cars. Seemingly, I could just replace the pipe myself. Perhaps if someone has experience and advice on this option as well? Thank You, Yasir