Simp

Hello to all,

I need your knowledge. For the past month the check engine light keeps coming on. I scanned the car with the OBD Fusion app on my iPhone and Codes C1201 (Engine Control System Malfunction) and P0430 (Catalyst System Efficiency Below Threshold)(Bank 2) pops up. I clear the codes each time hoping it doesn't come back but the engine light comes back on and it's the same codes. The car drives smooth! Even went on a road trip to Boston and Philly from NY recently and no problems. MPG on the highway is avg 22 and 18 avg in city. I went to Lexus to explain the code C1201 and the employee stated it could be something wrong with the brakes or drivetrain. But I changed the Brakes, Brake fluid and calipers (did not change the rotors because they still have life). I also went to a mechanic shop near me which I always go to who has experience working on Toyota and Lexus. One of the mechanics told me the C1201 could mean the computer is messed up and that the P0430 might mean I need a new Cat. But I am not going to buy a new Cat and he told me not to because I can buy a new cat and the code will still be there. I watched a Scotty Kilmer video on YouTube and he said I can take out the Cat and clean it with soap/laundry detergent. But I'm thinking of buying the product Cataclean: Fuel Exhaust System Cleaner for an easier method and it has great reviews. I also used Marvel Mystery Oil. Has anyone else experienced these codes and if so can you tell me what the issues were? Code it be possible that C1201 and P0430 are related? All recommendations are gladly accepted. Also if anyone lives in the NYC area, do you know of any other mechanic shops which specialize with JDM cars?

gs350fan

Check that the exhaust pipe isn't rotted out. Common in NY, and could cause that code. Air gets pulled into the exhaust pipe and the sensor reports it as a bad cat (there should be little to no oxygen after the cats).

ibidu1

iTrader: (1)

Welcome! First off what year and model is the car? If its awd as gs350fan stated check for leaks and take off the tin covering that surrounds the mid pipe, common issue on awd only

Simp

Thanks for the reply. I will check out the system to see if there is any rotting.

Simp

I have a 2008 GS 350 awd. I will check underneath the car and get back to you. If there is a leak, Do I wield new metal to cover the leak? Or do I have the option to get a brand new spanking exhaust system?

Simp

Thanks for the reply. I will check out the system to see if there is any rotting.

ibidu1

iTrader: (1)

Take it to a muffler shop, or jack up the car yourself and remove the tin metal covers that cover both sides of the mid pipe, aswell as the fiberglass packing. I wouldnt tell the muffler shop about the check engine light, so they wont bug you about up selling for a replacement cat, just tell them you have a leak, and maybe those smaller muffler shops are best to give you a 20-$30 quick weld.

Only AWD have this design flaw in that moisture gets trapped inside the metal and lays in the soaked fiberglass, especially bad for northern cars that see salt.

Its 10mm socket to remove it, but more likely all the nuts will be seized. If you have an angle grinder with a cut off wheel you can easily cut them off or even with strong tin snips. You should be able to see if the exhaust tubes are leaking, as any cracks will show carbon soot. If you have small hard to find leaks, then you can start the car and have someone with a rag block off both sides of the exhaust, and that should amplify the leak to maybe a whistle sound. But usually the leaks happen at the end of the mid pipe, near the exhaust clamps close to the o2 sensors.

Once you remove the tin you can see if you are able to save your old midpipe, and many times all that is needed is to weld that joint on the mid pipe. If theres a section of badly rotted tube, then you can have the exhaust shop cut that section off and weld in a new one. OEM Mid pipes are pricey! I dont like the aftermarket options.

Heres a pic off of ebay to show you the lay out
https://www.ebay.com/itm/LEXUS-2006-...EAAOSwVkZdrkzR