DPFE sensor?

How do I check the component DPFE sensor with a multimeter?

I have a 1997 Ford Taurus. 3.0Lv6 Manufactured in 08/97. I have a trouble code the Powertrain Control module has reported to an OBD2 device. Code p1401. This code is not in my book, but I have found on internet sources that it means the device is operating above 4.5 volts. What I want to do is "Backprobe" the circuit to check for actual operating voltages so I can find the problem. I really don't know what wires to back probe. The chilton manual says "To check the operation of the EGR backpressure sensor refer to the wiring diagrams and backprobe the correct connector terminals with your voltmeter. Check the signal voltage with the connector attached to the sensor and the engine running first while cold and then at warm operating temperature. With the engine cold there should be no EGR, and the voltage should be approximately 0.4 to 0.6 volts. As the engine warms up, Open the throttle to about 2000 rpm and check the voltage again, should be about 1.5 to 2.5 volts."

Although I cannot find in the wiring diagrams where it says anything about which wires to backprobe.
I believe it isnt there. I have looked.



P1401 DPFE (Differential Pressure Feedback EGR) circuit high input

Welcome to the forum!

Since you didn'g mention if you have the 3.0L 12V or the 3.0L 24V, I'm going to assume you have the 12V (Vulcan). Per the factory service manual, the ground for the DPFE is the Gray/red wire. The reference voltage is provided via the brown/white wire, and the signal to the PCM is the brown/light green wire.

Have you tried searching this forum for P1401? Others may have found sources for this code other than what the service manual (info below) suggests.

Also per the factory service manual, the following are suggestions for the P1401 code:
Possible causes:

-- DPFE SIG open.

-- DPFE SIG shorted to VREF or PWR.

-- VREF shorted to PWR.

-- SIG RTN open.

-- Damaged D.P.F. EGR sensor.

-- Damaged PCM.

-Rod

I recieved this information from another bbs system.

Key "ON", Engine "OFF".
Disconnect the DPFE connector and measure the voltage between the Grey/Red(VREF) wire and the Brown(Signal Return) wires. You should have approx 5 volts. If ok, proceed to step 3. If not ok, check for voltage between the VREF wire and Battery Ground. If voltage is now 5 volts, your SigRet ckt is open.
Reconnect the sensor connector.
Backprobe DMM positive lead into the Brown/Light Green (DPFE Signal) wire at the DPFE connector.Next,backprobe the DMM negative lead to the Brown(Signal Return) wire.You should have a voltage reading of 0.2-1.3 volts (Key On Engine Off). If your voltage is above 1.3 volts with the engine off, replace the DPFE sensor.
Ok,I now have tested the DPFE sensor as follows:

1.Key "on" engine "off."
2.Disconnected the DPFE connector and measured the voltage between the Grey/Red(VREF) wire and the Brown(Signal Return) wires.
Result 4.5v
3.Checked for voltage between the VREF wire and Battery Ground.
Result 5.0v
This tells me the SigRetCkt is open What is the SigRetCkt?
Also, Yes it is a 12 valve engine.

The SigRetCkt is Signal Return Circuit. All signals need a return path to complete the circuit. For the DPFE, this return path is provided through the Gray/Red wire (signal return). This wire coloring is from the factory Ford service manual for 1997 model year, so it should be correct. The signal return wire IS NOT the "brown wire." Also according to the service manual, two of the wires should be brown, one with a light green tracer and one with a white tracer.

What color are the wires on your connector, and are you sure it is the DPFE connector?

Your readings above would not indicate an open, but rather a high resistance path to ground, possibly due to corrosion or a loose connection, but since the wire colors don't match the service manual, I'm not sure I'd put much faith in them anyway.

-Rod

How do I check the component DPFE sensor with a multimeter?

I have a 1997 Ford Taurus. 3.0Lv6 Manufactured in 08/97. I have a trouble code the Powertrain Control module has reported to an OBD2 device. Code p1401. This code is not in my book, but I have found on internet sources that it means the device is operating above 4.5 volts. What I want to do is "Backprobe" the circuit to check for actual operating voltages so I can find the problem. I really don't know what wires to back probe. The chilton manual says "To check the operation of the EGR backpressure sensor refer to the wiring diagrams and backprobe the correct connector terminals with your voltmeter. Check the signal voltage with the connector attached to the sensor and the engine running first while cold and then at warm operating temperature. With the engine cold there should be no EGR, and the voltage should be approximately 0.4 to 0.6 volts. As the engine warms up, Open the throttle to about 2000 rpm and check the voltage again, should be about 1.5 to 2.5 volts."

Although I cannot find in the wiring diagrams where it says anything about which wires to backprobe.
I believe it isnt there. I have looked.



P1401 DPFE (Differential Pressure Feedback EGR) circuit high input

I don't want to offend anyone but you may be over analyzing this. Is the car running OK? If so you just had a hiccup in the EGR system. It's usually a chunk of carbon that hung the EGR valve momentarily. Erase the code and see if it happens again.

Ususally cleaning the EGR valve and DPFE sensor does the trick. Check the 2 small going to the DPFE sensor tubes for breaks.

Mostlikely it is the DPFE SENSOR, if you had a way to monitor the pid on a scanner and you see 4.5 volts its bad. i changed alot of these at the dealership pretty common problem. hope this helps you.