Exhaust Back Pressure Sensor

[lwillson]

Good Day

I wanted to share some info, I hope it isnt already posted somewhere on the forums and I am attempting to reinvent the wheel.

I plugged in the autoenginuity and was getting a p0470, Exhaust Back Pressure Sensor Circuit Malfunction. I also noted that the sensor was reading about 20 psi. I followed the website by guzzle (Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page) for cleaning out the tube and sensor. The tube was pretty much completely packed with soot, and so was the sensor. I cleaned out the sensor enough to see into it a 1/4 of an inch. I put it all back together, and started the truck up. I still had the code, and the pressure was still stuck at around 20 psi.

I then figured that the exhaust back pressure sensor was screwed, so I figured that anything I do to it now wont matter because I need a new one. I took an o-ring pick, and slowly started digging my way into the sensor and more and more soot kept coming out. I reinstalled the sensor and started up the truck. The p0470 was gone, and It was registering a small change in back pressure, but the value did not change much. I took the sensor off again, dug some more soot out, and hit it with the air compressor and kept going till I could not see any more soot coming out. I did notice a few little chunks of blue rubber come out, so I am pretty sure I scarred the rubber diaphragm on the inside of it. I was banking on getting a new sensor so I wasnt worried. I reinstalled it, fired the truck up and my code was still gone, and my exhaust back pressure was down to 14psi, and moved according to engine rpm instead of just being stuck at 20psi.

I have attached a picture to describe what the inside of the sensor looks like, in order to show where all the soot can hide. I think when I scarred the diaphragm, it was closer to the far edge of the blue area, so be careful when carving away at soot.

Hope this helps.

[dieseldan2005]

Good post. THanks for the info. I tried cleaning mine also and my code came back, so i just bought a new sensor.

[vitalidle]

Good info thanks Welcome to powestroke.org!

[NCHornet]

Soak it in brake cleaner and it will soften the carbon build up. Also International has the sensor for 1/2 the cost of Ford/
NCH

[jukka]

Hello Gentlemen
I can not open the cleaning page. Any other link please ?

Jukka

[vitalidle]

Hello Jukka the link is still working it must be filtered out on your end. I will send you a pm and see if I can get you a link to his site as it has lots of good info. Maybe we can get it to you by email

[Big K]

Just unplug it, it isn't needed except for the EBPV to operate during warm-ups.

(Drove me NUTS, plus most people CUT them and remove the EBPV).

I now have the EBPV Sensor Dongle

SP Diesel Main

I got it cheap from someone, works great!

[Big K]

SIGNAL FUNCTIONS
The EBP (Exhaust Back Pressure) sensor is a variable capacitance sensor that when supplied with a 5 volt reference signal from the PCM produces a linear analog voltage signal that indicates exhaust back pressure.

The EBP sensor's primary function is to measure exhaust back pressure so that the PCM can control the exhaust back pressure regulator when needed.

FAULT DETECTION MANAGEMENT
An EBP signal that is detected out of range high or low by the PCM will cause the engine to ignore the EBP signal and disable exhaust back pressure operation.

The NGS tool will display a fixed PID value of 43.5 PSI (300 kPa) for EBP when exhaust back pressure is in default.



After removing connector always check for damaged pins, corrosion, loose terminals, etc.
Connector Checks to Ground (B-)
(Check with Sensor Connector Disconnected and Ignition key off, all accessories off)
Test Points Spec. Comments
A to Grd. < 5 ohms Resistance to chassis grd. check w/key off, if > than 5 ohms harness is open -Signal Grd.
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground. - VRef
C to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground. - EBP signal

Connector Voltage Checks
(Check with sensor Connector Disconnected and Ignition Key On)
Test Points Spec. Comments
A to Grd. 0 - .25 volts If greater than .25 v signal ground is open or shorted to VRef or battery.
B to Grd. 5 ± .5 volts VRef check with key "ON," if voltage not in spec., see VRef circuit
C to Grd. 0 - .25 volts If greater than 0.25 volts, signal wire is shorted to VRef or battery.

Harness Resistance Checks
(Check with breakout box installed on engine harness only)
Test Points Spec. Comments
#91 to A < 5 ohms Resistance from sensor connector to 104 pin connector - Signal ground
#90 to B < 5 ohms Resistance from sensor connector to 104 pin connector - VRef
#30 to C < 5 ohms Resistance from sensor connector to 104 pin connector - EBP signal

Test Points Operational Voltage Checks
(+) #30 to (-) #91 (Check with breakout box installed in line with the PCM)
Voltage PSI KPAG Comments
.8-1.0 v 0 o Signal with key "ON" and engine OFF (Value dependent upon atmospheric pressure and altitude.)
.8-1.0 v 0 0 Normal warm idle signal.
1.19 v 14.8 10.0 Minimum signal expected at 2300 RPM with warm engine. (See EPR diagnostics)

Circuit Faults: Diagnostic Trouble Code Description
0472 = Signal voltage was less than .039 volts for more than 0.2 seconds.
0473 = Signal voltage was greater than 4.90 volts for more than 0.2 seconds.
__________________

[jukka]

Thank You Gentlemen

I just ordered the EBP sensor eliminator and will get rid of the noise.
Thank You for exelent help

Jukka