08' RR Catalytic Converter Failure

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Cthehentz

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The wifes 08' RR w/84k miles threw a code and the shop determined it was a bad catalytic converter, what would cause this with such low miles? I okayed the replacement of both ($1900) but this is the first time I have ever had to replace such item so I am a little skeptical.
 

Rex Rekstad

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I am with you on the skeptical part. The first thing I would do is check to see that they are in fact now brand new. I worked for a place that was notorious for putting on parts without putting on parts. Catalytic convertors only go bad from burning too much fuel inside them so if they went bad, there is another problem that needs to be addressed (leaking fuel injectors, intake air leaks...)
 

BendRover123

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I have a LR3 at 125000mi and it threw a catalyst on bank 2 depleted error, however after cleaning the downstream o2 sensors on both sides I haven't gotten the error again.

Just saying that might be the cheapest fix (~80$ in tools, 3hours wrestling with the sensors, use a torch to heat the threaded insert to release). Soak the sensor in gasoline for 8hours, and use MAF cleaner before and after.
 

DaytonaRS7

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I agree with the skepticism.

how did they diagnose bad cats? the only real way to know they are bad is by physically inspecting them. and a bad cat would usually have a slew of other symptoms such as misfires, bad performance and sometimes a rotten egg smell. were these present?

99% of the time, a simple code related to cats is remedied by replacing (or cleaninig) O2 sensors.
 

Cthehentz

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Little update, after I questioned the shop they replaced the 02 sensors, PVC valves and updated the computers software but the same code would show up after several drive cycles. The last thing they replaced were the catalytic converters, you can feel the difference with increased performance and it feels more spunky. I also verified these were brand new...
 

BendRover123

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Just an update:

  1. first i did the liquid mechanic treatments, do not work at all after you atop using them so dnt waste your money
  2. replaced downstream catalytic converters, again does not work
  3. used spacers to take them out of the exhaust flow, this in fact removed the code: HOWEVER high fuel consumption opposite of running lean issue remains
  4. next stop, use spacers with 90deg angle to even further remove sensors from exhaust flow
BTW i know my catalyst is depleted but there should be no reason you need to replace them.

I have a LR3 at 125000mi and it threw a catalyst on bank 2 depleted error, however after cleaning the downstream o2 sensors on both sides I haven't gotten the error again.

Just saying that might be the cheapest fix (~80$ in tools, 3hours wrestling with the sensors, use a torch to heat the threaded insert to release). Soak the sensor in gasoline for 8hours, and use MAF cleaner before and after.
 

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