So as the title states, I have 2 codes that WILL NOT CLEAR! With an OBDII scanner, as soon as you erase the codes, you do not even have to start the car and the same 2 codes will reappear. P0113 and p0447. However, the check engine light on the dash is NOT on, but I know for a fact the bulb is not out, and is working. I can't get my car inspected with these codes constantly remaining on?!?!

 

I hate these inspections. It will not pass because of the stupid obd II test. I would suggest you fix whatever the issue that's causing the codes.

 

But why are these codes persisting? They shouldn't be there still if you completely erase them, and before the car is running, still brings the code back?!

 

They will be there until you fix the issue. Something is wrong with your car you cant just clear them and have them stay off if there is a problem.

P0113 - The powertrain control module (PCM) monitors the temperature of the air entering the engine. The PCM supplies a 5 volt reference voltage to the Intake Air Temperature (IAT) sensor. The IAT is a thermistor that varies resistance based on temperature. As the temperature increases, resistance decreases. Low temperature results in a high signal voltage. When the PCM sees a signal voltage higher than 5 volts, it sets this P0113 check engine light code.

P0447 - Evaporative Emission Control System Vent Valve/Solenoid Circuit Open

This code is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the model. What does that mean? The Powertrain Control Module (PCM) has detected an open within the circuit that controls the vent valve or solenoid for evaporative emission systems vapor. As fuel sits in the tank it lets out fuel vapor, while driving this vent opens and allows the vapors to be circulated into the engine intake manifold, a charcoal canister or into the atmosphere, depending on the vehicle. This vent valve is apart of the simple, yet complicated evaporative emissions system. Symptoms Symptoms of a P0447 DTC will include Malfunction Indicator Lamp (MIL) illumination, you will likely not notice any other symptoms. Causes Potential causes may include: Faulty vent valve Wire/circuit issue PCM fault

 

You have an aftermarket intake? Try to clean you MAF sensor too.

 

I do have an AEM intake, but that is it. The IAT sensor, is the one ON the pipe next to the oil cap, right? If so, I am replacing it today. i was also told that when something like the IAT goes out, I will get the 0447 code regardless. IDK if that is true or not. BTW Oldschool350z, great info and detail!!!

 

I just googled the codes lol.

You may find more info if you search on here or Google. But the codes are coming back on because your car is trying to say something is wrong

 

You should bench test the part before you replace it. Throwing parts at a problem is more or less a crap shoot. In the end, it usually costs less to take your car to a recommended shop where they can do a proper test and fix the issue.

 

without reading all the jibber jabber it sounds like u have some electrical issues. so when u turn the key on the ecu does an automatic self test on certain circuits. and ur have problems.
so the car does not need to be running for the ecu to see (example) voltage is out of spec, or there is no resistance in the circuit when normally there should be 10ohms.
check the codes, then check the parts, if they check out check the actual circuit.
ALWAYS ALWAYS ALWAYS check the easiest simplest thing possible, plugs actually connected? is there corrosion in the plug on the terminals? go ova that basics first, then move a step deeper, then deeper still if u have not found the problem.

 

Well said.