SES light on - please help

cheezmunky · #1 02-08-2006, 05:31 PM

I have a '98 GTP and my SES light came on earlier this week but the car seems to be running fine. The only problem I have noticed is that when idling, my water temp goes a lot higher than I have ever noticed it going. It goes back down again once I start moving. I took it to autozone and it gave the code p1404 and something about emission control. Any help would be greatly appreciated.

BNaylor · #2 02-09-2006, 08:32 AM

DTC P1404 is EGR valve circuit performance error. During that test the PCM commands the EGR valve closed but it is detecting it is stuck open. You either have a wiring problem at the EGR valve or a defective EGR valve and solenoid. You can try removing the EGR valve and cleaning it. It may be carboned up. The pintle should move freely.

cheezmunky · #3 02-10-2006, 01:50 AM

this probably sounds stupid but there isn't any way that could somehow affect the water temp is there?

BNaylor · #4 02-10-2006, 02:04 AM

Quote:

Originally Posted by cheezmunky

this probably sounds stupid but there isn't any way that could somehow affect the water temp is there?

It is possible. With the EGR valve stuck full or partially open hot exhaust gases are constantly being fed into the intake system at the lower intake manifold. This may cause a change in fuel injector pulse width which may cause either a lean (most likely) or rich condition which could cause overheating, etc. It is best to resolve the EGR issue and see what happens.

cheezmunky · #5 02-10-2006, 02:29 PM

thanks

cheezmunky · #6 02-22-2006, 06:28 PM

after I took my car to autozone, they reset the light and it hasn't come back on but I went ahead and inspected the egr valve anyways. I wasn't really sure what to look for but the pintle moved freely. Where should I be looking for carbon buildup? The gasket didn't look so well and the paint on the valve was flaking off. Could that be from heat damage? I am still having the heating problem as well. Any suggestions? thanks

richtazz · #7 02-23-2006, 07:10 AM

If the coolant temp sensor is slightly out of range, it could be confusing the PCM with an erroneous reading, causing it to "think" the coolant is warmer/cooler than it actually is. The CTS may be gunked up with sludge, which would cause it to read incorrectly. The PCM uses the signal from the CTS to turn the cooling fans on also. If you decide to change the CTS, while you have the cooling system open, change the T-stat if you haven't recently and see what happens.

BNaylor · #8 02-23-2006, 08:10 AM

Quote:

Originally Posted by cheezmunky

after I took my car to autozone, they reset the light and it hasn't come back on but I went ahead and inspected the egr valve anyways. I wasn't really sure what to look for but the pintle moved freely. Where should I be looking for carbon buildup? The gasket didn't look so well and the paint on the valve was flaking off. Could that be from heat damage? I am still having the heating problem as well. Any suggestions? thanks

That is interesting. Paint peeling off the EGR. I'd keep an eye on it just in case. It gets very hot but not supposed to get hot enough to peel off the paint. When you check for carbon you need to look at the EGR pipe and mount which goes to the exhaust and to the lower intake manifold. If the gasket doesn't look good it should be replaced.

If the ECT (engine coolant temperature) sensor is out of calibration it can be checked with a multimeter in ohms position. See chart below:

Sounds like you just need a good cooling system flush if you have never done it before. Get rid of the Dexcool and use Prestone Extended Life coolant. A lot of us have switched over.

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