Ok I drove to my cousins shop and I turned off the check engine light off like a month ago. He checked the ECU with the ECU reader and the light was off but he still got a couple codes. There is a knock senor code and all the O2 sensors are out. Also there is a problem with the 3rd gear ratio in the transmission. I can't pass the inspection with that. I want ot know why the light wasn't on though with all these problems. Also he reset the codes and the knock sensor code comes back immediatly.

 

Does the light actually work? With the key in the ON position, the CEL bulb should light up.. (with all the other cluster lights).

If it lights up then I dunno whats up with the codes being stored but the light being off.

If it doesn't light up when the key is "ON", then you need a new bulb.

If the 0304 comes back right away (with NO other codes), its time for a new KS. Check the resistance, the grounds and harness etc. first, but most likely the KS is bad.

In NY do they do an actual emissions test or just check for codes or both as part of the inspection?

 

ghost codes...eventhough you manually set them off, the parts are still fouled, so they would always show up on a scan.

 

No way o2 sensors will NOT set the CEL - the bulb might be blown.

 

yeah, on second thought, njmodi is right. i only have heard of KS ghosts, not O2...

 

Well the light came back on while I was driving home. It decides to go on when it want's too. But when I turned the car on the light didn't even turn on. I know what you talking about how it turns on then off but nah, he was also saying that. Weird man. Maybe I did something wrong when I reset it. Does the screw on the ECU have to stay in a certain postition when your finished like to the right or to the left?

Also in NY they check the codes and do emissions. They just changed it. It used to be just emissions but no no more.

 

The screw should be turned all the way anti-clockwise (i.e. to the left), once you are done retrieving codes.

 

I'd check the stickies on the position of the ecu screw. I believe its all the counter clockwise. My screw is jacked and pretty much keeps spinning in either direction.

 

Check screw to the left when finished.. but if its to the right I think your idle goes all whack

 

Well that fixed one of my problems but the light went off drove a lil and came back on. I did not think that the screw would screw around with the idle. Thanks no more shaking and having to put in nuetural.

 

When your KS is bad your engine sets itself to default "safe" timing tables. Should give you some inspiration to change it, basically you should get more power when you fix it.

 

NY just checks for codes atleast anywhere out of NYC.......they hook up to teh OBDII Diagnostic port and check for codes...but no actual sniffer

 

Your monitors must be "set" in order to pass the OBD2 test, the light might be off , but if the monitors are not set - you'll fail the monitors test.

next time you hook up your car to scanner, have them check your monitors, to make sure they are set, it takes certain amount of driving under certain conditions to set those monitors

Nick.

 

Keep in mind that you can't just run to get inpected soon after resetting the ECU. It takes a couple hundred miles (to be safe) for the ECU to hit its "full ready" state.

 

A broken knock sensor won't throw a CEL code. You usually find out about it when another part of your car breaks. When I had my Nissan Truck (before my Maxima) I had an O2 sensor throw a code. After I put in a new sensor and reset the ECU I went straight to DEQ and passed it. Resetting it clears all codes.

Replacing the knock sensor is SO fun. One of the few things in life that makes me glad that I have small hands.....