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Hey all I am having an issue. 93 4.9 the truck is overcooling and its pulling code 332/334. Replaced te thermostat and egr valve. still overcooling and pulling code. Any ideas. I'm looking at throttle position sensor next.
Should mention code 332/334 are both egr codes and I checked for restrictions in tube and leak test showed no leaks. The codes appeared at the same time as the overcooling
Code 332: EGR valve opening not detected.
Code 334: EVP circuit above the closed limit of 0.67 volts.
You replaced the EGR valve, but did you verify it is being told to open? Has someone removed the vacuum source? Is the EVR operational?
Code 334 indicates the closed value is too high so that tells us the EVP is connected, but it is probably faulty in light of you already replacing the EGR valve.
I had to go get a vacuum tester and I was going to test the vacuum solenoid next and the position sensor and go from there. Also I don't know if this is true on a truck this old but my buddy told me you have to put some miles on an egr after replacement to stop the check engine light. But this came at the same time as the overcooling so I assume its PCM trying to compensate for something. That's what brought me to throttle position sensor.
What he is talking about is after you replace a sensor you have to disconnect the battery for about 15 minutes, re-connect the battery and then drive the truck about ten miles for it to relearn the sensors.
This does not apply if you change an Actuator just a sensor.
A EVR is a Actuator.
A EVP is a Sensor.
This all has nothing to do with the check engine light or MIL being on after you change something.
If the light is still on then you need to recheck the codes in CM.
Found it thanks for all the help no vacuum in front of vacuum solenoid tested behind it and was fine sprayed it out and some silver something came out now egr is opening. Still gonna stash those links thanks again.
Found it thanks for all the help no vacuum in front of vacuum solenoid tested behind it and was fine sprayed it out and some silver something came out now egr is opening. Still gonna stash those links thanks again.
The "overcooling" is probably caused by a faulty temperature sending unit or a bad gauge. More then likely the former. Do not confuse the temperature sending unit for the Engine Coolant Temperature (ECT) sensor. Two different beasts with two different functions.