code 334
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Mountain Pass
Joined: Aug 2014
Posts: 158
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From: Venice FL.
code 334
93 f350 7.5- Truck's been running good, Then yesterday, start it up and running rough at idle. Drove home, about 15 mins,not running quite right,but got home. Pulled code 334. Is this an EVP sensor issue?
Would that cause my symptoms?
Would that cause my symptoms?
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Was the code displayed in the KOEO tests or Stored Codes from Continuous Memory?
Code 334: EVP circuit above the closed limit of 0.67 volts.
This can be caused by a faulty EGR valve, EVP sensor or the EGR Valve Regulator (EVR) could allow vacuum through to the EGR when it is not supposed to.
It's a process of elimination.
Code 334: EVP circuit above the closed limit of 0.67 volts.
This can be caused by a faulty EGR valve, EVP sensor or the EGR Valve Regulator (EVR) could allow vacuum through to the EGR when it is not supposed to.
It's a process of elimination.
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Mountain Pass
Joined: Aug 2014
Posts: 158
Likes: 3
From: Venice FL.
This is the first time I ever checked codes. I jumped the test connections on the EEC,turned the key on,engine not running, and counted the flashes.It seemed to show the same code like 4 times, then stopped,
I shut the key off, and then did it again, and got the same results. Is there a way to disconnect the EGR operation to see if that makes a difference?
I shut the key off, and then did it again, and got the same results. Is there a way to disconnect the EGR operation to see if that makes a difference?
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
There are two parts to running the KOEO and Stored Code display. Any issues flagged in the KOEO tests will be flashed twice. Once the KOEO codes are flashed out there is a single Separator flash to indicate any Stored Codes from Continuous Memory will be displayed. It looks like you got Code 334 for both KOEO and Stored Code display.
Since the engine was not running and you got Code 334 that means the EGR valve position feedback is above .67 VDC with no vacuum applied. This can be caused by carbon build up that prevents the EGR valve from fully closing. Or the valve could simply be stuck in some position from build up. Try inspecting and cleaning it. You should be able to manually move the valve with a screwdriver or apply vacuum to it.
If the EGR valve checks out good then it could be a faulty EGR Valve Position (EVP) sensor. The problem is the EGR valve applies some preload to the EVP sensor so it could still be a bad EGR valve. Although the common failure mode is the internal spring gets weak over time which allows the EVP value to drop below .67 VDC when the valve is supposed to be closed.
Since the engine was not running and you got Code 334 that means the EGR valve position feedback is above .67 VDC with no vacuum applied. This can be caused by carbon build up that prevents the EGR valve from fully closing. Or the valve could simply be stuck in some position from build up. Try inspecting and cleaning it. You should be able to manually move the valve with a screwdriver or apply vacuum to it.
If the EGR valve checks out good then it could be a faulty EGR Valve Position (EVP) sensor. The problem is the EGR valve applies some preload to the EVP sensor so it could still be a bad EGR valve. Although the common failure mode is the internal spring gets weak over time which allows the EVP value to drop below .67 VDC when the valve is supposed to be closed.
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Mountain Pass
Joined: Aug 2014
Posts: 158
Likes: 3
From: Venice FL.
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Fleet Owner
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From: Kentucky
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