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Discussion Starter #1
I'm getting code 34 (CM, valve above closed limit), been getting it for a while. I decided that my EGR valve and not the solenoid or EVR (which is new) were to blame, so I pulled the EGR valve to clean it.

Anyways, I can pull air from the flange that bolts to the intake, but not from the lower portion that goes to the exhaust tube unless the valve is open with vacuum. The valve holds vacuum just fine so the diaphragm or EVR rubber gasket is just fine.

How is this even possible? and am I definitely stuck with getting a new EGR valve? ridiculous that these things are $100.. I just don't understand how I'm getting code 34, how I get no leakage to the exhaust tube, both the EVR and EVP test out fine.. this is driving me nuts
 

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The Anti Yam!
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I'm getting code 34 (CM, valve above closed limit), been getting it for a while. I decided that my EGR valve and not the solenoid or EVR (which is new) were to blame, so I pulled the EGR valve to clean it.

Anyways, I can pull air from the flange that bolts to the intake, but not from the lower portion that goes to the exhaust tube unless the valve is open with vacuum. The valve holds vacuum just fine so the diaphragm or EVR rubber gasket is just fine.

How is this even possible? and am I definitely stuck with getting a new EGR valve? ridiculous that these things are $100.. I just don't understand how I'm getting code 34, how I get no leakage to the exhaust tube, both the EVR and EVP test out fine.. this is driving me nuts
If it is a CM code it means it "Has" happened, not is happening. Clear the codes by interrupting the test and drive it to see if it re-appears.

If it does re-appear, but only on memory codes than your EEC is intermittently receiving a signal from the EVP that is not possible from a properly functioning unit. Either the EVP is bad, or you have a wiring problem.
 

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yo,
DTC 34 - EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary.

DTC 34 "...in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates that the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem..."
Source: by rla2005 (Randy) via miesk5 at http://broncozone.com/topic/22091-throttle-position-sensor-trouble/

DTC 34; Next isn't listed by anyone for the 34 Code, but is a good test anyway to rule the EVR out & is a simple multimeter test; The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed. When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere. To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times. With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
Source: by miesk5 at Ford Bronco Zone Forums

More EGR (Valve & EVP) info & test LINKs in my site @ http://www.broncolinks.com/index.php?index=146
 

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Discussion Starter #4
I found out it's actually pulling air through the lower portion of the valve at the inspection holes. I'm not sure what the inside looks like, but I think there is a gasket between the top and lower portion of the valve that keeps it airtight when not open and that gasket has broken apart. I wish the thing wasn't crimped and you could seperate it (where the screws are?) I'd be able to fix it.. It's not carboned up or anything, diaphragm is fine. Oh well, guess I need a new valve.
 

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The Anti Yam!
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If it does re-appear, but only on memory codes than your EEC is intermittently receiving a signal from the EVP that is not possible from a properly functioning unit. Either the EVP is bad, or you have a wiring problem.
Allow me to amend this, it was not accurate.

34 = (KOEO/KOER) PFE or EVP circuit above the closed limit of 0.67 volts.
34 = (CM) PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.


The EEC is not receiving a signal from the EVP that the EGR is closing. Either the EGR is not fully closing, the EVP is bad or you have a wiring problem.

Test the EVP both on and off the EGR, if it tests good replace the EGR.
http://www.fordfuelinjection.com/index.php?p=35

Sorry for the misunderstanding :toothless
 
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