Code 401 "insufficent EGR flow. Now what?
Laughing Gas
Joined: Nov 2003
Posts: 794
Likes: 3
Do a search on here this is very very very common problem and is a relatively easy fix if you can use a socket wrench. Basically you have to take the tbody & intake elbow off the engine and clean carbon out of the egr ports, *most likely*
but do a search thers tons and tons of threads about this.
but do a search thers tons and tons of threads about this.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Awful when you don't know what's behind a number!
It's an EGR performance diagnostic failure code.
There is a metal tube that runs from the drivers side exhaust manifold to the EGR valve, up top of the motor.
When the EGR is commanded to open, the flow is measured by a sensor.
This sensor is telling you the flow is too low vis 401 code.
Reasons could be the EGR passage is blocked, the sensor is faulty or it's attaching hoses are faulty and anything that could affect the system as a whole.
Testing:
1. Try opening the EGR while the engine is running. The engine should get rough from this indicating the EGR and passages are ok.
2. Inspect the DPFE mounting hoses and stand pipe for faults.
3. If nothing is found, the DPFE sensor is suspect.
This is not all there is to how the system works but is enough for you to get a handle on it using logic. The DPFE is hanging off two small metal pipes with short small hoses located right near the power brake Booster. It has a connector on it.
Testing the EGR requires you to remove it's vacuum hose and apply vacuum from a hand pump or in some manner to suck it open with engine vacuum or 'otherwise'.
You can either clear the code with a reader, unhook the battery for 5 min or let two drive cycles do the testing and put the lamp out if it passes.
It's an EGR performance diagnostic failure code.
There is a metal tube that runs from the drivers side exhaust manifold to the EGR valve, up top of the motor.
When the EGR is commanded to open, the flow is measured by a sensor.
This sensor is telling you the flow is too low vis 401 code.
Reasons could be the EGR passage is blocked, the sensor is faulty or it's attaching hoses are faulty and anything that could affect the system as a whole.
Testing:
1. Try opening the EGR while the engine is running. The engine should get rough from this indicating the EGR and passages are ok.
2. Inspect the DPFE mounting hoses and stand pipe for faults.
3. If nothing is found, the DPFE sensor is suspect.
This is not all there is to how the system works but is enough for you to get a handle on it using logic. The DPFE is hanging off two small metal pipes with short small hoses located right near the power brake Booster. It has a connector on it.
Testing the EGR requires you to remove it's vacuum hose and apply vacuum from a hand pump or in some manner to suck it open with engine vacuum or 'otherwise'.
You can either clear the code with a reader, unhook the battery for 5 min or let two drive cycles do the testing and put the lamp out if it passes.
