I received the mentioned codes, 14 and 32, today sitting in a fast food line. The dash temp skyrocketed to 300˚. Got home and it didn't seem that hot, started it some time after and no codes appeared (didn't reset them) but again after driving for about 10 minutes the SES light on and verified that I probably have something going on with these 2.

I have an 85, the ECT sensor was replaced about 2 months ago so I'm not 100% sure it already failed. The EGR code came up one time when I was diagnosing things a couple months ago too, it never came back after I reset the codes. I did notice getting out that the car smelled unusually rich, which could be a result from a failing EGR?

Anyways, I did a visual inspection of the wiring but will look at it again in the morning. Can these codes trigger one another? If so, is there a root cause? If anyone has encountered this problem or has some information on the two (if one can affect the others "performance") I'd love to get some information.

Thanks

 

Maybe. I don't know the '85 or the L98. Is DTC 14 coolant sensor circuit fault on your model year?

The comp uses coolant temp as one of the factors to determine if it should open the EGR valve.

I don't know but I suspect the EGR valve on the 85 was one of the types that was "bang-bang" operation meaning it was either opened all the way or closed all the way. I also suspect it moves the plunger by vacuum on a diaphram. If so you can check it by putting a hand held vacuum pump on it's vacuum connection and with the engine at idle draw a vacuum and it should cause it to run rough and eventually die. EGR valves foul with carbon over time and need replacing or cleaning. I'm not sure how buried it is on your L98 but consider pulling it off for a cleaning using something that will not damage the diaphram.

300 degree coolant temp is kinda hard to believe. With a 15 pound cap and 50/50 mix it should boil at about 256 degrees. The temp sensor is basically a resistor that will change resistance with temp. Maybe you can look up a test for it and see if it tracks with temp change doing some off vehicle test?

Things to check would be what the actual temp is and does the EGR valve open and close. I know it sounds strange but intoducing hot exhaust gas into the intake lowers combustion temps and that is part of how the emissions system deals with NOx.

 

if the DCT14 is 'engine coolant temp (ECT) sensor circuit' on your year, it could be bad sensor.

As mentioned, sensor is a variable resistor where resistance is inversly proportional to temps (e.g. 241 ohms = 194 F; 177 ohms = 212 F).

One other thing which could cause this is low coolant and nothing but steam at the sensor location (thermostat housing on your year?).

So you might want to also check for proper coolant level and bleed any air in/around the thermostat housing (if your year has a bleeder).