My son just bought a 2003gt with a 4.6L eng. It has new cats and 02 sensors. It did not pass the readyness test when we tried to get the emission test done. The check engine light is not on and it shows no codes when connected to a scanner. The only thing is the car will not pass the cat test when connected to the scanner.

 

Were the new parts just installed? A lot of the time if new parts were installed the car needs to be driven so the ECU can settle in. I just smogged mine and I made sure it was good and hot for the test. It makes a huge difference.

 

The I/M readiness tests require that several drive cycle series be completed--click here for more.

 

I have driven the car approx 500 miles with multiple start/stop cycles. The parts were installed just proir to that. As to it being hot I have done that also.

 

Do you know what components of the readiness test are failing? This requires a scan device that can read PIDs (Parameter IDs), PID 0101 in particular:

The value returned by PID 0101 is 4 bytes, bit-mapped as follows:



Knowing which test failed is obviously a good thing...

 

It did not pass the catalyst test. I am going to put it on the scanner again this afternoon to see if it has any codes after about another 100 miles.

 

I just finished putting the car back on the scanner. It is not passing the catalyst test, oxygen sensor, oxygen sensor heater, and evaporative systems. I think the catalytic test wil not pass because of one of the other things not passing. One odd thing is the front heaters are cycling on and off but the back ones are not.

 

If the rear sensors are disabled in the tune the heaters will not cycle, the OBD2 readiness tests for the rear O2 sensors will never complete, and the cat tests will fail because of no data from the rear sensors--any possibility of their having been turned off?

 

What county do you live in? I may be able to hook you up with a different place to get emissions done so you don't have to worry about that ****.

 

We are in cobb county