p0401 intermittent issues
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From: Charleston
p0401 intermittent issues
I have a 96 4.0L that is throwing an EGR flow code error (P0401) and stalling out after it drives for a while. The time it will run varies. Sometimes it could be a few hours and sometimes it could be 15 minutes. If I let it sit for about an hour after it dies I can crank it back up.
So far I have replaced the DPFE sensor, the EGR valve and the EGR pressure feedback sensor. None of this has resolved the issue.
What else can I do?
Welcome to the forum
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
Do you have a vacuum gauge?
Good tool to have, $10-$15
It reads like you may have a clogged exhaust, either Cat Converter or Muffler has broken up inside
You can test for that with vacuum gauge
Or unhook the vacuum hose on the EGR Valve and plug the hose end with a screw/bolt
Will get the P0401 but should be no issues in driving at all, so no stalls or no starts......if its an EGR issue
The way the EGR system works is that the DPFE(differential pressure feedback) sensor measures pressure in two places, the exhaust manifold and at the EGR valve's end of exhaust tube
When computer opens the EGR valve there should be a pressure drop at the EGR end as exhaust flows into the intake
P0401 means there was not
This is code often a clogged exhaust tube which you would have seen if you replaced EGR, I am assuming
EGR system will only work after engine is fully warmed up, and only when accelerating or cruising at highway speeds, it is there to reduce cylinder temps to lower NOx production when engine is under a heavier load
But in any case your description of the problem doesn't read like an EGR issue
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
Do you have a vacuum gauge?
Good tool to have, $10-$15
It reads like you may have a clogged exhaust, either Cat Converter or Muffler has broken up inside
You can test for that with vacuum gauge
Or unhook the vacuum hose on the EGR Valve and plug the hose end with a screw/bolt
Will get the P0401 but should be no issues in driving at all, so no stalls or no starts......if its an EGR issue
The way the EGR system works is that the DPFE(differential pressure feedback) sensor measures pressure in two places, the exhaust manifold and at the EGR valve's end of exhaust tube
When computer opens the EGR valve there should be a pressure drop at the EGR end as exhaust flows into the intake
P0401 means there was not
This is code often a clogged exhaust tube which you would have seen if you replaced EGR, I am assuming
EGR system will only work after engine is fully warmed up, and only when accelerating or cruising at highway speeds, it is there to reduce cylinder temps to lower NOx production when engine is under a heavier load
But in any case your description of the problem doesn't read like an EGR issue
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