96 Ranger code still P0401
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Junior User
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From: Enola
96 Ranger code still P0401
EGR flow insufficient. Well I replaced the EGR Valve twice and the DPFE for inspection last September. The light came on in March. I had the Air Conditioner on last month for the first time this season and it stalled. I started it and got about a mile and it stalled again even with the AC off at that point. I had to do this a few times until I got home. I replaced the EGR valve since that was the only code. I turned the light off and it came back on two days later. Anyone have any idea what else gives this code?
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From: SW Va
The EGR isn't on line at idle, so if it isn't cloged up & sticking open, I might suspect an acting out IAC, causing it to want to stall at idle.
But get the code/s pulled & post the number/s that turn up.
Did you replace the DPFE with OEM, or aftermarket????
But get the code/s pulled & post the number/s that turn up.
Did you replace the DPFE with OEM, or aftermarket????
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From: Enola
I pulled the codes just before I posted on this forum. P0401 is the only code I get. I replaced the DPFE with an aftermarket product from Pep Boys. BWD is the name brand of the DPFE and is made of black plastic. The box that the DPFE came in says EGR 155. It only stalled that one day until I replaced the EGR valve. Not saying that is what caused my truck to stall but it hasn't stalled since I replaced the EGR valve and I havn't ran the air conditioner since.
I will try cleaning the steel tube going to the EGR valve. The rubber hoses that go to the DPFE don't look bent or collapsed but I will clean them too and look for leaks.
I will try cleaning the steel tube going to the EGR valve. The rubber hoses that go to the DPFE don't look bent or collapsed but I will clean them too and look for leaks.
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From: SW Va
OK good feedback, so you don't have any other codes stored
Be sure to check the EGR VSV, as any internal problems with it's diaphragm leaking can cause a hidden vacuum leak & problems with it trying to control the EGR valves operation.
I'm not famaliar with the quality of the DPFE sensor brand you used, but just because it's new, shouldn't automatically earn it a pass, as I've seen plenty of bad new parts, right out of the box!!!!
Maybe consider doing the operational test listed in the "Tech Info" thread.
You may have more than one problem, so if the engine won't idle up when you turn the A/C on, then maybe suspect the IAC.
More things to ponder, let us know how it goes.
Be sure to check the EGR VSV, as any internal problems with it's diaphragm leaking can cause a hidden vacuum leak & problems with it trying to control the EGR valves operation.
I'm not famaliar with the quality of the DPFE sensor brand you used, but just because it's new, shouldn't automatically earn it a pass, as I've seen plenty of bad new parts, right out of the box!!!!
Maybe consider doing the operational test listed in the "Tech Info" thread.
You may have more than one problem, so if the engine won't idle up when you turn the A/C on, then maybe suspect the IAC.
More things to ponder, let us know how it goes.
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From: Enola
Below is a DPFE Test from this link: http://rockledge.home.comcast.net/~r...tage-Test.html
I get 5 volts but how does this tell me that the sensor is bad when it is unplugged and I am not measuring the voltage on the DPFE sensor? I am measuring the voltage on the wire going to the DPFE sensor. I am getting 5V on the DPFE signal and 5V on the VREF. 0V in the middle. Could I be doing something wrong?
__________________________________________________ ___________________
FORD DPFE SENSOR TEST
What you are trying to do here is to check the voltage output of the DPFE sensor. Initially it should read around .45 - .55 volts or .8 - 1.0 volts @ KOEO, depending on the application (that's because DPFE sensors will have either a 0.55 voltage offset or 1.0 voltage offset). Use the table below for guidance, but you should check to be sure which offset is used by your vehicle's DPFE sensor:
Aluminum or Black Plastic Housing
(1.0 voltage offset)
- All Others
1. Make sure the Key is ON and the Engine is OFF (KOEO);
2. The wire harness remains plugged into the DPFE sensor for this test;
3. Check DPFE SIG for .45 - .55 volts or .8 - 1.0 volts (as per the above table);
4. If DPFE SIG at KOEO is not within the indicated range, then the sensor is faulty and should be replaced;
I get 5 volts but how does this tell me that the sensor is bad when it is unplugged and I am not measuring the voltage on the DPFE sensor? I am measuring the voltage on the wire going to the DPFE sensor. I am getting 5V on the DPFE signal and 5V on the VREF. 0V in the middle. Could I be doing something wrong?
__________________________________________________ ___________________
FORD DPFE SENSOR TEST
What you are trying to do here is to check the voltage output of the DPFE sensor. Initially it should read around .45 - .55 volts or .8 - 1.0 volts @ KOEO, depending on the application (that's because DPFE sensors will have either a 0.55 voltage offset or 1.0 voltage offset). Use the table below for guidance, but you should check to be sure which offset is used by your vehicle's DPFE sensor:
Aluminum or Black Plastic Housing
(1.0 voltage offset)
- All Others
1. Make sure the Key is ON and the Engine is OFF (KOEO);
2. The wire harness remains plugged into the DPFE sensor for this test;
3. Check DPFE SIG for .45 - .55 volts or .8 - 1.0 volts (as per the above table);
4. If DPFE SIG at KOEO is not within the indicated range, then the sensor is faulty and should be replaced;
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Joined: Jan 2004
Posts: 13,851
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From: SW Va
Below is a DPFE Test from this link: http://rockledge.home.comcast.net/~r...tage-Test.html
I get 5 volts but how does this tell me that the sensor is bad when it is unplugged and I am not measuring the voltage on the DPFE sensor? I am measuring the voltage on the wire going to the DPFE sensor. I am getting 5V on the DPFE signal and 5V on the VREF. 0V in the middle. Could I be doing something wrong?
__________________________________________________ ___________________
FORD DPFE SENSOR TEST
What you are trying to do here is to check the voltage output of the DPFE sensor. Initially it should read around .45 - .55 volts or .8 - 1.0 volts @ KOEO, depending on the application (that's because DPFE sensors will have either a 0.55 voltage offset or 1.0 voltage offset). Use the table below for guidance, but you should check to be sure which offset is used by your vehicle's DPFE sensor:
Aluminum or Black Plastic Housing
(1.0 voltage offset)
- All Others
1. Make sure the Key is ON and the Engine is OFF (KOEO);
2. The wire harness remains plugged into the DPFE sensor for this test;
3. Check DPFE SIG for .45 - .55 volts or .8 - 1.0 volts (as per the above table);
4. If DPFE SIG at KOEO is not within the indicated range, then the sensor is faulty and should be replaced;
I get 5 volts but how does this tell me that the sensor is bad when it is unplugged and I am not measuring the voltage on the DPFE sensor? I am measuring the voltage on the wire going to the DPFE sensor. I am getting 5V on the DPFE signal and 5V on the VREF. 0V in the middle. Could I be doing something wrong?
__________________________________________________ ___________________
FORD DPFE SENSOR TEST
What you are trying to do here is to check the voltage output of the DPFE sensor. Initially it should read around .45 - .55 volts or .8 - 1.0 volts @ KOEO, depending on the application (that's because DPFE sensors will have either a 0.55 voltage offset or 1.0 voltage offset). Use the table below for guidance, but you should check to be sure which offset is used by your vehicle's DPFE sensor:
Aluminum or Black Plastic Housing
(1.0 voltage offset)
- All Others
1. Make sure the Key is ON and the Engine is OFF (KOEO);
2. The wire harness remains plugged into the DPFE sensor for this test;
3. Check DPFE SIG for .45 - .55 volts or .8 - 1.0 volts (as per the above table);
4. If DPFE SIG at KOEO is not within the indicated range, then the sensor is faulty and should be replaced;
Now follow steps 1 & 2, & with the electrical connector on the DPFE sensor, back probe the SIG voltage at KOEO & tell us what it reads.
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Junior User
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From: Enola
Ok plugged in I am getting 4.91V for the top (DPFE signal) and 5.03V for the bottom (VREF). I cleaned the metal tube yesterday and light is still on. My DPFE Sensor has specifications with it saying the KOEO is 1 volt with plastic bodies. I am getting 5.03V and the sensor is only 8 months old. Of course this is the only receipt I can't find for this truck to take it back if that is even possible. If this DPFE is defective, what causes it to become defective? Since the old one went out originally.
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Joined: Jan 2004
Posts: 13,851
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From: SW Va
I don't think I was clear, was the above 4.91 volt reading on the "SIG RTN" lead????
You can read up on DPFE SIG RTN voltage verses applied vacuum & vacuum leak testing here
http://www.tomco-inc.com/Tech_Tips/ttt36.pdf
If you don't have a hand vacuum pump to test the DPFE, most autoparts stores have them in their "Loan-A-Tool" program, for a refundable deposit.
Let us know how it goes.
You can read up on DPFE SIG RTN voltage verses applied vacuum & vacuum leak testing here
http://www.tomco-inc.com/Tech_Tips/ttt36.pdf
If you don't have a hand vacuum pump to test the DPFE, most autoparts stores have them in their "Loan-A-Tool" program, for a refundable deposit.
Let us know how it goes.
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zippy the pinhead
1983 - 2012 Ranger & B-Series
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Apr 8, 2004 01:17 AM
