Sick97SS

My check engine light seems to come on during random times about once a week, then goes away. Took it to autozone and they scanned out.....

PO400 EGR flow malfunction

PO113 IAT Sensor/Circuit high input

The EGR Code has me confused as to what to check. All my EGR vacume lines seem ok i don't know what else to look for.

I was using the 5.7k resistor mod for the IAT but removed it because of negative feedback with the mod on this board. This was about a week before the SES light started comming on.

Any ideas??

Also i believe i have false knock becuase my car falls on it's face at high rpms, what type of tool do i need to read knock. Scanmasters? Actron Scanners? which will and which won't check degrees of knock. im looking to invest in a scanner just don't know which one to get.

Injuneer

P0113 = IAT sensor circuit high (= low temp). That means the circuit for the IAT sensor is "open".... either the wire or harness connector has a break in it (intermittent) or the sensor itself is broken. Its easy to check the sensor with an ohm meter.

P0400 = EGR system low flow detected. Means when the PCM activates the EGR valve, it doesn't see the expected change at the MAP sensor. With your long tubes and ORP, you probably don't have enough back pressure to give the required EGR flow. Or the valve is not opening, the valve pintle or the opening in the manifold is carboned up, the EGR vacuum solenoid is plugged or the vacuum source is interupted.

Sick97SS

thanks Injuneer...
going my your info i have so far replaced my IAT sensor with a brand new one, and when i pop it on and off th connector i can actually hear the car change noise so i know it's working.

Also took off my EGR valve and cleaned it out to the best of my ability. seems to be working ok. I can stick my finger in the holes on the side of the EGR when the car is running and it starts stumbling and poping. So the valve is working ok. How can i test if the solenoid is working or not. Is there a vacume (neg pressure) in the EGR lines at idle? because if so i cant feel it.
The EGR only works at higher speeds for gas milage right?

Im just out of ideas and don't know what else to check. thanks in advance.

Injuneer

The EGR does not operate at idle. And it isn't used for gas mileage, its used to reduce combustion chamber temps when you are lugging the engine at lower RPM, to reduce the formation of NOx. Also does not operate above 3,500RPM.

With the engine at idle, unplug the solenoid harness connector (the SES light will go on for the loss of continuity on the circuit). Unplug the vacuum line that goes to the EGR valve. Apply a ground to one side of the solenoid and 12V to the other. The valve should open and you should feel vacuum at the nipple that the vacuum line would attach to.

If you have a vacuum pump, don't start the engine. Apply vacuum to the engine side of the solenoid. Then power up the solenoid and feel for vacuum on the EGR side. That way you could avoid the SES light, resetting it, etc.