I know they give you directions on the how to's section, but I heard that if you disconnect the negative cable on your battery for 15 mins, the ECU will reset thus not having the check engine light. I need to do this so I can smog my car cuz here in California they wont even smog it if the engine light is on. thanks anybody. this might be the wrong place for this post, but i couldnt figure out which one would be best.

 

Clear the errors correctly by fixing the problem first. Use the method of clearing codes via the ECU screw under the dash. The process is in the stickys at the top of this page.

If you simply clear the error code and still have a recurring problem, when you go to inspection and they plug into your OBDII they will either see an error or get a "not ready state" causing you to fail even if the light is off.

 

I agree completely................the EPA had a cute trick built into the OBD II standards to prevent clearing the codes just before going to inspection, doing it either by use of an OBD II scanner, or powering down the ECM will result in a "not ready/incomplete" reading (not enough "cycles" on the ECM) when they run the "I/M Readiness Test", which will result in a "Fail"..................

 

If you don't want to do it yourself, you can take it to a local service shop and have then reset it for about $30.

 

i wish i can disconnect the battery and the problem went away...lol...

 

You can take off the neg. battery terminal to clear dash CEL, it has to be off for 24 hours or more. It is easy to find the ecu and reset it yourself. Just take off the plastic piece near gas pedal, turn key to acc, with a tiny flathead turn right to stop wait 2 sec. left to stop wait 2 sec. repeat a couple times. Next start no CEL. If you f@ck it up its not my fault, many people break these screws, just be gentle. It only turns a little each way, make sure you put it back to the left when your done.

 

So what? He will STILL FAIL INSPECTION........................

 

Depending what is wrong, a CEL can come up for a number of reasons, sometimes they mean nothing and can be cleared w/o affecting inspection.

 

And the car will still fail..............all OBD II units have a "fail safe" built into their software at the behest of the EPA that will cause the unit to read out "not ready" if it has been reset just prior to inpspection........the unit must run a minimum number of start/stop cycles and "on time" prior to the "I/M Readiness Test" now run. This feature was designed to catch this exact action.....................

 

Take the car to a parts store with an OBD scanner (Autozone, Advance Auto, for example) and they will check the fault. It may be something easy to fix or there may not be a fault. They will reset the CEL and sell you any parts you may need.

Regarding the inspection, if he fixes the fault and resets the CEL, will it still read "not ready"?

 

Yes, the ECM will read "Not Ready". The code built into the OBD II system requires that the vehicle go through a series of cold starts, warm up, run at speed and shut down/cool off without any codes before the system will pass the "I/M Readiness Test" protocol. Otherwise the system will read out "Not ready", meaning the prescribed number of cycles has not been met. The only ones that are allowed to circumvent this are dealers or independant shops in states with state inspection certifications that are allowed to "testify" that the repairs were made. Then can repair the car, clear the codes and allow it to pass, providing that they assume responsibility for the repairs having been properly executed. Some states now also require that independants electronically file the OBD inspection records from the car with the state, creating a trail. "Big Brother" and all that....................

 

You can pass inspection with a variable speed sensor code, there are more I am not going to list them. These codes and some others do not affect emissions or safety, they will know you have these but they can not fail you for them. So don't act like you know every states requirements, JFP in Pa.

 

What I do know is the federal standards, which most states follow; I'm also sure you can always find a state station, or an independant inspection station, which will go a different way, ususally at their own risk. And, while not all codes will cause the I/M Readiness test to fail; but most states will not even look at a car with any MIL's present. However, I am NOT aware of ANY STATE that will purposely let a car slide on an I/M Readiness Test; which was my orignial statement, as to do so would deny them Federal funds for highway upkeep. So, I'll reapeat: Anything that will cause a "not ready" on an I/M Readiness Test will most likely fail you, period. If you want to take that as "acting like I know every state's code requirements", so be it; but I know I am correct on this point.......................

 

http://www.smogtips.com/passing_inspection.cfm

 

My point, exactly..............................

 

Yea.. thats pretty much the general rule all over. I dont know whether or not each state may have certain requirements, or be lenient in certain areas, but I know for sure in NY if your car is '96 or newer, any CEL means failure until the car is repaired and the CEL is cleared.

 

for a 97 5sp there are 8 selftests the ecu has to complete. just by starting it and driving for 5 min will complete about 4. You need 6 completes to pass. This is in cali. Go to your local smog guy and ask him for the obdII book, in there he will tell you the 12 steps it takes to complete all 8 selftests.

 

Wait, is the Key supposed to be set to "On" or "ACC"? I've read in multiple places that both say "On" and "ACC". What happens if you try to reset your ECU with it's turned to the "ACC"? Does it even matter?

 

Again with the old thread revivals.

If the key is in Accessory, the ECU gets no power. Hence, no code reading.

It's a very simple procedure: