Engine Codes CEL, HELP !

[crivas13]

I have a 94 Explorer Limited 2WD and im getting this check engine light. At first it would come on when passing someone on the highway now it comes on about 10 seconds after i start it. I went to Autozone and they checked the codes and here's what they got:
335335 Long Pause 1214336214336 we ran it a couple of times and it came out the same both times. The guy couldnt tell me for sure what was wrong. I tried changing the EGR Pressure sensor but that didnt help. I've reset the battery constantly and still nothing is helping.

 

[Texplorer]

Thats a long code, are you sure there isnt a space inbetween any of those numbers?

 

[crivas13]

Thats how the guy wrote them down as he was reading them. Im guessing the first line is 335 335. On the second set he said it could be 12 | 14 | 33 which check out in the code book but the rest 6214336 i dont know.

 

[MrShorty]

I wasn't there, so I can't be absolutely sure, but here's how I see that code sequence.
335 335 = KOEO hard fault code 335
long pause
1 = separator pulse between the KOEO hard faults and continuous memory codes.
Then two continuous memory codes 214 and 336 (repeated twice just like the hard fault code).
First thing to do is resolve the hard fault. You've tried replacing the pressure sensor (or whatever it is on this EGR system), now check out the rest of the circuitry for any breaks, shorts, or other issues.
And, after you get the KOEO code resolved, don't forget to run the KOER test before jumping into those continuous memory codes.
And, finally, I would suggest you learn to read the codes yourself. It's real easy, only requires a paper clip, and then you aren't dependent on the folks down at Autozone to do it for you. Instructions can be found in several places like www.dalidesign.com/hbook/eectest.html

 

[Glacier991]

Great post and good advice as usual MrShorty. Guys if you haven't figured it out, he's a pro and knows his stuff!

 

[crivas13]

Thanks for the code help. I tried checking the system hoses and the EGR Valve selenoid has 2 wires, 1 going to the EGR valve and 1 going into the engine. The one going to the engine has a vaccum but the one going to the EGR Valve doesnt, I tried it this morning because someone told me it should vaccum when the engine is cold. So is it probably this selenoid? I tried checking and Autozone does not have it.

 

[crivas13]

I tried changing the selenoid, still no vaccum to the EGR Valve. Any ideas?

 

[MrShorty]

I'm not real familiar with the EGR system on these, because my '92 doesn't have one. I don't know when it should have vacuum to the valve. If you want to test the solenoid, try the output state test (refer to above instructions). I expect that solenoid would fall under the umbrella of solenoid controls that that test tests.
One note, you diagnose a KOEO hard fault first because you know the fault must be electrical (with the engine off, all related parameters such as engine vacuum or exhaust pressure are not there). The pinpoint test mentions to first, check the vacuum hoses to the sensor for plugging. Then check the wiring between the sensor and the PCM (I know it can be tedious tracing wires and reading wiring diagrams, but sometimes it needs to be done). Check the Vref voltage at the sensor.
I would suggest you get a hold of the full circuit test. You can often find manuals with this information at libraries.

 

[bmonahan]

crivas13 - did you ever resolve the 336 error code? If so, how.