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Toyotapro, ASE master tech
Category: Toyota
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Experience:  ASE Certified, 10+ years Lexus and Toyota Certified
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Toyota Camry: fine..the second catalytic converter..pipe

Resolved Question:

I have engine light on for a few years on my Toyota Camry 96 but the car seems to be running without any noticeable problem. Several years ago I took my car to a mechanic for some exhaust problem,perhaps some catalytic converter issue. The mechanic advised that the car would run fine without the second catalytic converter so he cut it off and welded the pipe. The car had been running fine without the second converter. Sometimes later the engine light came on. I was not sure if it was due to the second missing converter. I took the car to another mechanic who tested with a code computer and told me that it needed the catalytic converter. Two years ago the car failed the emission test. The mechanic worked on the car for over an hour doing different tests and said that EGR valve needed to be replaced. He did something to pass the car in emission test and charged me $200. The car was running OK but the engine light did not go away. The emission is due again this month. I replaced the front header pipe or the flex pipe with a catalytic converter today. I took the car for emission test immediately after the new flex pipe and catalytic converter was installed at a local Meineke shop. The emission mechanic told me to bring the car back in a couple of days because the catalytic system was not ready. The engine light also came on after 30 minutes of driving. Couple of weeks ago I had taken the car to another exhaust shop and they checked the codes and found the code for the EGR valve. I am still not sure if the problem is with the EGR valve or there some other issue causing the engine light to come on. EGR valve is expensive and before buying a new EGR valve I want some advice if it is actually the bad EGR valve that is causing the engine light to come on. Any advice/help to correct this problem would be greatly appreciated.
Submitted: 7 years ago.
Category: Toyota
Expert:  AdvanceAuto replied 7 years ago.

First thing you have to do is find the exact trouble code that it is setting. If the catalytic converter is missing or faulty then it will set either a P0420 (catalyst efficiency below threshold Bank 1) or P0430 (catalyst efficiency below threshold Bank 2). These codes usually indicate a failed or missing catalytic converter or an oxygen sensor that is not responding. If it is an ExaustGasRecirculation code then it could be a P0401-EGR Insufficient Flow. Usually on these cars the valve don't do bad and the problem is usually the EGR Vacuum Solenoid. One way to check it is to unplug it and connect 12volt battery power and grounds to the solenoid terminals and it should operate/click, open/close. This is a common problem on this model.

(Item is called VSV for EGR on picture)

First picture is for a 4Cylinder

Second picture is for a V6


Customer: replied 7 years ago.
I took the car to a Advance Auto Parts retailer. They checked with a coumputer and found code P0401- insufficient flow through EGR. Is this problem easy to fix or I have to take the car to a shop. How much it would cost to fix this problem. Any suggestions.
Expert:  Toyotapro replied 7 years ago.
P0401 is a common issue on these cars as they gain age and mileage. A vaccum pump needs to be used to be sure that the EGR vavle still operates and the ports are not clogged, 99.9% of the time this issue is resolved by replacing the EGR vaccum switching valve that is located on the back side of the block as well as the modulator valve.
Toyotapro, ASE master tech
Category: Toyota
Satisfied Customers: 9974
Experience: ASE Certified, 10+ years Lexus and Toyota Certified
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Customer: replied 7 years ago.
Is it possible that a DIY person can correct this problem by following step by step instructions. I would appreciate any help if you can guide me so I could correct this myself and the car passes the emission inspection. I would be glad to add bonus dollars ($10 -$20) or any other bonus you think appropriate for your service.
Expert:  Toyotapro replied 7 years ago.
Sorry but realistically a DIY replacement of these is hard to do, reason for this is because the vaccum switching valve for the EGR valve is located on the back side of the engine block ust above the driveshaft, this requires access to a lift and some creative tool setups to get to the bolt that holds this in place. The modulator valve sits nest to the EGR valve and is a 15 second swap.
Customer: replied 7 years ago.
a local shop says that intake manifold needs to be cleaned of carbon buildup. He would charge $ 175. Another shop says to replace the EGR valve. It would roughly cost about 300. A third shop says to replace the vacuum switch or valve for a total parts and labor to be around 240. I am confused. Is it a good idea to replace the EGR valve or to clean it. The valve is expensive. Any recommendations
Expert:  Toyotapro replied 7 years ago.

You are not getting an accurate diagnosis by these shops, they are simply guessing.

No do NOT replace the EGR valve, that is not the issue. As long as the car will idle or stall when vaccum is applied to the egr valve then all you need to do here is replace the vaccum switching valve and the modulator.