oh.... P1401

[brwntom]

98 2.5 auto trans

Ive replaced the egr pressure sensor 2 times. (autozone warranty) still getting the code. the pins are not bent. What to do next? fuel economy is suffering and I do not know what to do!

Help!!!

Tom

 

[rtg143]

Code P1401-Differential Pressure Feedback Electronic (DPFE) sensor signal was over 4.0 volts.
Enabling conditions: Engine off self test.
Blocking Action: This code can block the following monitors: Fuel control, O2 monitor, catalyst, misfire, and EGR monitor.
Testing: Check for an open ground for the sensor, damaged sensor or a short to 5 volt reference in the signal wiring.

Engine Off:
The EGR can’t have flow with the engine off, The engine off voltage is the base line for engine idle testing. The normal voltage is 0.45 to 0.60 V sensor range. The new plastic low profile sensor is the 0.9 to 1.1 V version with some of the older versions being the new 0.9 to 1.1 V version too. If the signal voltage is wrong check the 5 V reference and ground before replacing the sensor.

5 Volt Reference Check;
Note: 5 V reference is shared with other sensors.
The sensor requires 5 Volt reference to operate properly. Check for 4.9 to 5.1 V using battery – as reference. If voltage reading is too high, check the grounds because they are the most likely cause of a high reference voltage
reading. Low 5 V reference is usually caused by a short to ground.
Sensor Ground Check;
Check for 0.050 volts between sensor ground at the sensor and battery negative. Note: Sensor ground is shared with other sensors.
Normal ground voltage and reference voltage with wrong signal voltage indicates the sensor is bad.
If the voltage is too high check the voltage on the PCM ground to battery negative.
– High voltage indicates the PCM to engine ground or battery to engine ground is bad.
– Normal PCM ground voltage with high sensor ground indicates a prob-
lem at the PCM connector or inside the PCM.

 

[brwntom]

Its suppose to rain here for the next.... well, as far out as the forecast goes. Ill pull it in my garage tomorrow and let you know what I find.

Thanks,
Tom

 

[db796]

Where do u guys find the codes is there a spot on this site that shows what they mean...? if so could one of u guys get a link could be useful for me...

 

[2813josh]

Where do u guys find the codes is there a spot on this site that shows what they mean...? if so could one of u guys get a link could be useful for me...

In the tech library under "computers"

 

[db796]

In the tech library under "computers"

Allright thanks alot!!!

 

[brwntom]

I know its been like 10 months since this problem developed but I've been super busy and finally had time to get around to this. I tested the voltages for the 3 wires to the DPFE switch. The ground shows 0V, power shows 5V, and the reference shows 5V. I thought there was an internal short in the computer. I picked up a junkyard unit, having the same issue. I have also replaced the DPFE again. Once again, i am stuck. HELP

Thanks,
Tom

 

[brwntom]

I still need help with this.

Tom

 

[rtg143]

Have you tried running vacuum to the EGR valve and see if the engine runs rough or dies? Take both hoses off of the DPFE, start the truck and see if exhaust comes out. Both hoses are on and not blocked?

 

[Thed]

Your little tube in the intake that goes from the valve to the intake might be clogged. Carbon likes to build up in the intake...

Before:

After:

 

[Mazda]

Check out this site it will help you with your problem.

http://easyautodiagnostics.com/ford_egr_test/ford_egr_valve_1.php

Also check the hoses to DPFE. make sure they are not cracked or clogged. Are they connected top the EGR pipe.

Bryan

 

[brwntom]

neither of the hoses are cracked or clogged. When vacuum is applied to the egr valve the engine stumbles and almost dies. Im starting to lean towards a short in the wiring?

Tom

 

[Earl43P]

There are only 3 wires to check then.

BN/LG wire goes to Pin 65 of the PCM (Brown wire with LG stripe). This is the actual DPFE signal wire.

GY/RD wire goes to pin 91 of the PCM. This should be the 5v reference voltage.

BN/WH goes to Pin 90 of the PCM. Signal ground.

Good links:
http://www.tomco-inc.com/techinfo.aspx
http://www.tomco-inc.com/Tech_Tips/ttt36.pdf

 

[thoorn]

Brwntom,

Did you ever get this solved? I am having the same issue on my Ranger. I am getting p1401 code and get 5V on both vref and the signal line (pins 1 and 3). I was thinking that maybe the PCM is bad but then saw that you changed yours and it didn't help.

 

[cvar]

I changed my DPFE & hoses, and p1401 went away. Yay!
BTW, stick to Motorcraft DPFE (I bought mine $74 from Rockauto), cuz they lasted longest. Whereas other manuf DPFE failed prematurely.