error code help

[the manzo]

hi i have a 93 explorer 4x4 and i have four engine error codes that i dont know how to fix.

the first code is: 335-EGR sensor voltage out of range
the second code is: 124-throttle position sensor voltage higher than expected
the third code is: 327-EGR valve pressure transducer/postion sensor curcuit below minimun voltage
and the fourth code is: 332-EGR valve opening not detected

 

[MrShorty]

When you have several codes, usually the best approach is to resolve the KOEO codes first (see my notes on pulling EEC-IV codes if you are not sure how to distinguish KOEO from CM codes).

My code list indicates that the 335 has to be a KOEO code, so I'll probably recommend starting there. A KOEO 335 indicates some fault in the EGR's DPFE circuit. This is fairly common on these. I'd probably check the wiring to make sure it isn't something cheaper, then replace the DPFE. Then clear CM, test drive, and pull codes again to see what (if any) codes return.

 

[the manzo]

ok thanks ill try that. but do you think that reseting the computer would help?

 

[MrShorty]

It doesn't seem likely to me. A KOEO code (assuming the 335 is a KOEO code) is a hard fault where the fault condition existed at the time the test was performed. It would only take a few minutes to reset the computer and see if it helps, but I would not expect it to.

 

[the manzo]

i reset the computer today and after about five or so miles, it popped on again. i changed the egr valve sensor and the engine light is still on.

 

[MrShorty]

Are you still getting all the same codes? If you reset the computer before the repair, you'll need to clear codes and test drive to make sure you are getting the most recent codes.

 

[the manzo]

ok, i just scanned and cleared the codes and i got error code 335 and 332. when i cleared the codes i took it for a test drive. the only time the codes come on are when i bog the engine.

 

[the manzo]

do you think replacing the egr valve itself would fix error code 332?

 

[MrShorty]

I expect the CM 332 has the same cause as the KOEO 335. Since the 335 is set with the engine off, it almost has to be electrical in nature. I doubt replacing the EGR valve is going to have any effect on a KOEO 335.

As common as it is for the DPFE sensor to fail, I'm a little surprised that replacing it didn't fix the issue. If we assume the new DPFE is good, that means the problem is likely a wiring fault between the DPFE and the PCM or something internal to the PCM.

Next thing I'd probably do would be to carefully check the wiring to the DPFE sensor and make sure it is good. I'm not familiar with the specifics of the DPFE circuit. Get a wiring diagram, check for 5V Vref at the DPFE, and make sure there are no breaks in the wires going back to the PCM.

 

[jd4242]

does a 93 even have egr?didnt think they started till 94

 

[the manzo]

yes. 93 does have an egr valve

 

[the manzo]

I expect the CM 332 has the same cause as the KOEO 335. Since the 335 is set with the engine off, it almost has to be electrical in nature. I doubt replacing the EGR valve is going to have any effect on a KOEO 335.

As common as it is for the DPFE sensor to fail, I'm a little surprised that replacing it didn't fix the issue. If we assume the new DPFE is good, that means the problem is likely a wiring fault between the DPFE and the PCM or something internal to the PCM.

Next thing I'd probably do would be to carefully check the wiring to the DPFE sensor and make sure it is good. I'm not familiar with the specifics of the DPFE circuit. Get a wiring diagram, check for 5V Vref at the DPFE, and make sure there are no breaks in the wires going back to the PCM.

ill check the wiring tomorrow. where is the pcm located

 

[MrShorty]

The PCM is behind the kick panel, below the glove box, just in front of the passenger door.

 

[the manzo]

ok the check engine light only comes on when the engine is warmed up.

 

[MrShorty]

That could be expectedd, as the computer is probably waiting until the engine is warmed up before deciding the EGR system isn't working and turning on the CEL.
What happens if you perform the KOEO test on the engine cold? Note that you will likely get KOEO 116 and 114 codes because the engine is cold. If the KOEO 335 goes away cold, that suggests that the electrical fault is only present when hot. If it's still there, the fault is present whether hot or cold.

 

[the manzo]

when i scan it, hot or cold, error code 332 and 335 appear

 

[MrShorty]

It sounds like it is time to get a wiring diagram and go through the DPFE sensor circuit carefully.

 

[the manzo]

so the error code is not coming from a faulty egr valve. i fount a hose the leads from the intake to the heads. i noticed that there was moisture around it on the head. so i put silicone around it. hopefully that solves the problem. but when i was doing that, i snapped a plastic hose comeing from the egr valve sensor. what size is the plastic hose?

 

[the manzo]

i replaced the broken hose. the engine light only comes on when it is under load. could the pcm still be running off the vacuum leak error?

 

[MrShorty]

Because KOEO codes are set with the engine off (no vacuum), I would not expect a KOEO 335 to be set by a faulty vacuum hose. I also would not expect the PCM to remember a faulty vacuum line after it has been replaced like you are describing.

Assuming you are still getting a KOEO 335, I would still suggest going through the DPFE sensor circuit.