I tried searching this but had no luck. I had some doug thorley headers, no name aftermarket cat and a flowmaster 60 series installed with 2.25 inch piping. The check engine light is now on. Had my neighbor check it out said it's a code 21 71. If he is not mistaken he said 21= o2 and 71=egr. Why did this occur? What can I do to check this out & fix this? Has this happened to anyone else after installing exhaust? Anything helps thanks in advance. Ps: i live in California where they are strict on emissions
O2-probably damaged the wiring. Might have poisoned the sensor with rtv, paint fumes, dirt, ???? use the troubleshooting flowchart to check it. EGR I'm kinda surprised since last I checked, Toyota just used a temp sensor to see if hot gasses are going through the EGR passages. On the other hand, EGR flow is dependant on the pressure differential between the exhaust and intake manifold. If you alter that ratio (by changing exhaust flow-rate) you alter EGR behavior. Any of the passages getting plugged up, blocked off, or otherwise altered will change behavior as well.
Where can I find this chart? I'm going to upgrade the manifold gasket to and aftermarket one. Hopefully that's the issue.
Do the doug thorleys have the o2 plug anywhere on them and if so is was it connected after the swap.There are two on the stock set up.Here on Guam we don't have emissions so we don't have to worry about it but if you swap out your headers and don't plug in the 02 sensor it will read code 21.In the past I have found where the wires had touched the exhaust and melted together and it gave a code 21.
It's not on the headers it's just before the cat and right after. I might just swap out the o2s see if that helps
That's the one I ment before the cat my bad. But no it's right where it is suppose to be about a foot or so from where the headers start