Throwing a code after tune...what gives?

[Sonic04GT]

I just had my 2004 GT tuned by a known reputable tuner yesterday when the car started throwing a P0405 - EGR Sensor A Circuit Low. Have you guys heard of this happening before? I believe he just ended up shutting the EGR off after playing with it for about 20-30 minutes. Are there any issues with this? I cleared the code and as soon as I start my car the code re-appears. It hasn't thrown a Check Engine Light though. Is there a way to troubleshoot this before I take the car back to him? He is obviously aware of the problem and counter-acted it by disabling the EGR apparently so I don't think that will accomplish too much.

What issues could I run into in its current configuration?

The only other cause I can think of is we put Marvel Mystery Oil through the small vacuum port on the plenum a week or 2 ago to make smoke and trace an exhaust leak. Whatever didn't get burned off is probably just sitting in my exhaust system. You'd think the car would have burned the rest off by now from the heat but I haven't noticed any smoke. When I had my muffler clamps removed and welded the other day he said there was a decent amount in there.

Could this have gotten to the EGR sensor? I'm a noob and somewhat unsure of how the EGR processs works and how these sensors are linked.

I really don't want to start tracing wires back to my PCM.

Could it be the valve?

I was told it could be a DPFE sensor, but those seem to go for about $40 which I don't want to spend if it really isn't bad and it's just the tune or wiring, or oil that hasn't burned away. If you guys think it'll fix the problem, relating to that code, I'll go pick one up. I read somewhere that if the DPFE sensor is bad it'll probably throw a different code.

This is what Diablosport said...
"If he turned off functions related to the EGR you should not be getting trouble codes. You’ll need to consult with the tuner to see if the custom tune itself needs adjustment.

-Mike M"

 

[wmburns]

I can not find a P0405 in my reference. Are you sure the code isn't P1405?

If so, inspect the vacuum lines to/from the DPFE sensor for leaks. Exhaust gasses are hard on the rubber parts making the lines brittle. It's hard to fully inspect these lines because of interference from the firewall.

Next pull and clean with electrical contact cleaner the DPFE and EGR vacuum solenoid electrical connector. Re-grease with a small amount of silcone di-electric grease (same kind used on spark plugs).

>>>
P1405 - DPF EGR Sensor Upstream Hose Off or Plugged

While driving, the EGR monitor commands the EGR valve closed and checks the differential pressure across the EGR orifice. The test fails when the signal from the DPF EGR sensor indicates EGR flow is in the negative direction.

Upstream hose is disconnected
Upstream hose is plugged (ice)
Plugged or damaged EGR tube

Look for signs of water or icing in hose
Verify hose connection and routing (no excessive dips)
Verify DPF EGR sensor proper mounting and function (view DPF EGR PID while applying and releasing vacuum directly to sensor with a hand pump)

 

[Sonic04GT]

I just went and took a look. You're right, hard to really see anything with the firewall in the way. I didn't want to remove any hoses but they appear to be ok. Followed the vacuum line back to the plenum and that looks fine too.

View attachment 204903

I noticed today when I started the car it was idling kind of rough. Put the AC on for a second and when I shut it off the RPMs dropped below 500.

After a couple minutes it smoothed out but will still spike between 720 and 780. Average is about 740.

 

[Sonic04GT]

Double post

 

[wmburns]

CLEAN the electrical connections to the DPFE sensor and EGR vacuum solenoid. A circuit malifunction is usually a wiring problem or a poor electrical connection.

 

[Sonic04GT]

CLEAN the electrical connections to the DPFE sensor and EGR vacuum solenoid. A circuit malifunction is usually a wiring problem or a poor electrical connection.

I will do that tomorrow as it's starting to rain. If it still throws a code should I go ahead and replace the DPFE? I can't imagine tracing back to the PCM.

Duralast/EGR Valve Pressure Sensor (SU2108) | EGR Valve Pressure Sensor | 2004 Ford Mustang GT 8 Cylinders X 4.6L SFI SOHC | AutoZone.com
Advance Auto Parts: EGR Pressure Feedback Sensor by BWD - Part EGR155

Could it have anything to do with the solenoid?
http://shop.advanceautoparts.com/we...BWD_20470133-P_1420_R|GRPEMISAMS_784381394___

If I recall, the harness itself looked good on the DPFE and the solenoid. Didn't check the parts themselves though.

I got an O2 circuit slow response code as well, but I saw that about a week ago and cleared it. Wouldn't surprise me if it's from that MM oil.

Just got off the phone with my tuner. Said he turned the EGR off twice, so it shouldn't be throwing a code. Taking it back to him tomorrow to turn the EGR back on and see what happens. Will still probably read a circuit error regardless.

Ford wants over $100 for a DPFE, OUCH. I'll try the $45 one from Autozone with a 2-year warranty.

 

[wmburns]

Regarding slow O2 response, oil contamination is listed as one of the causes.

From my personal experience, I seldom have good luck diagnosing EGR problems on my personal cars. More often than not, the problem turns out to be (in order):

• Bad DPFE sensor. This includes leaks in the vacuum lines
• Clogged TB EGR passageways
• Bad EGR valve

However, your DTC is very specific. It is either a bad DPFE sensor, loose/corroded wire, or bad PCM (unlikely).

I usually start diagosing an EGR problem by replacing the EGR valve (not likely in your case). I then end up replacing the DPFE. Then about 25% of the time, end up finding a blockage in the TB EGR passageways.

NOTE, have stated before that a vacuum leak in the lines to/from the DPFE can cause this DTC.

If you can't find an obvious electrical problem to the DPFE sensor, replacing it is a reasonable step. Another option is to measure the voltage BN/LG and GR/RD wire. Post.

I recently help another forum member. After tons of tests, we narrowed the problem down to a DPFE wiring fault or a bad PCM. He finally gave up and went to the dealer. The problem turned out to be corrosion in the DPFE electrical connector. Turns out that he did not take my advice and THROUGHLY clean and di-electric grease the connector. The Ford mechanic simply cleaned it and it worked perfectly.

OBTW, I found the DTC codes. Must have keyed in the wrong MY.

>>>service CD
P0405 - DPF EGR Sensor Circuit Low Voltage Detected See DTC P1400

P1400 - DPF EGR Sensor Circuit Low Voltage Detected: The EGR monitor checks the DPF EGR sensor signal to the PCM for low voltage. The test fails when the average voltage to the PCM drops to a voltage less than the minimum calibrated value.

DPFEGR circuit short to GND
Damaged DPF EGR sensor
VREF short to GND
Damaged PCM

A DPF EGR PID reading less than 0.2 volt with the key ON and engine OFF or running, indicates a hard fault.

 

[Sonic04GT]

Can you explain to a noob how to test it? I have a multimeter. Do I just pull the harness off and test one of the pins on the harness that connects to the DPFE with the vehicle running or just on? If it's above .2 then the sensor is bad?

Do you think that marvel mystery oil could have ruined the o2 sensor regarding the other code? Is it possible to clean it? Will it eventually burn off from the heat?

I'd hate to replace it and find out there's more oil in there only to ruin it again. I'll just park on a really really steep hill and let it all run out the tailpipes haha

 

[wmburns]

Please, please, please make the first thing done to clean the electrical connector. This may solve the problem without additional fan fare.

Get yourself a mirror on a stick. Use a bright light to inspect the DPFE vacuum lines. Feel around the lines for dry rot or other defects.

To test the DPFE sensor output, back probe the wires with a DC volt-meter. It will help to have test leads with a very small tips. If you simply disconnect the electrical connector, then you are NOT testing the DPFE.

The O2 sensors can be removed and cleaned with brake clean. I suspect it will burn off the oil sooner or later. Can't really answer how much oil it takes to ruin an O2 sensor. You are own your own.

 

[Sonic04GT]

Please, please, please make the first thing done to clean the electrical connector. This may solve the problem without additional fan fare.

Get yourself a mirror on a stick. Use a bright light to inspect the DPFE vacuum lines. Feel around the lines for dry rot or other defects.

To test the DPFE sensor output, back probe the wires with a DC volt-meter. It will help to have test leads with a very small tips. If you simply disconnect the electrical connector, then you are NOT testing the DPFE.

The O2 sensors can be removed and cleaned with brake clean. I suspect it will burn off the oil sooner or later. Can't really answer how much oil it takes to ruin an O2 sensor. You are own your own.

I'll have to go get some of that cleaner and grease tomorrow, and a mirror. do you just use a toothbrush or what?

Are you talking about the 2 large hoses that plug into the DPFE? All the thin vacuum lines running to the solenoid/DPFE/plenum look good. I ran my fingers along the 2 near the fire wall that run into the exhaust tube from the header and those felt ok but I'll check with a mirror tomorrow.

I don't know what I was thinking with disconnecting the harness. For some reason, an input was running through my mind, not output to the PCM lol

Do I need to put some kind of anti-seize on the O2 sensors before I put them back in? Just spray them with brake cleaner and thats all?

 

[wmburns]

A little bit of anti-seize on the O2 threads will make it easier to remove the next time.

A tooth brush is a good idea. Also, get an spary type electronic contact cleaner. The spary can get into places a tooth brush can't.

There are only two vacuum lines to the DPFE. Both go to the EGR tube.

 

[Sonic04GT]

A little bit of anti-seize on the O2 threads will make it easier to remove the next time.

A tooth brush is a good idea. Also, get an spary type electronic contact cleaner. The spary can get into places a tooth brush can't.

There are only two vacuum lines to the DPFE. Both go to the EGR tube.

Yeah I got ya. There was a vacuum line running to the solenoid too, and of course the valve.

I will pick those items up tomorrow and pull the DPFE off. Thanks for information. I'll let you know what happens.

 

[Sonic04GT]

Cleaned it this morning with CFC elextrical cleaner (contacts already looked really good.) Greased it with Permatex dielectric and nothing. Bought a new sensor today...
Duralast/EGR Valve Pressure Sensor (SU2108) | EGR Valve Pressure Sensor | 2004 Ford Mustang GT 8 Cylinders X 4.6L SFI SOHC | AutoZone.com

Still throws the code as soon as I clear it. The P1000 readiness test is still there but I don't think PCM readiness should affect these codes.

 

[wmburns]

What about this test?

If you can't find an obvious electrical problem to the DPFE sensor, replacing it is a reasonable step. Another option is to measure the voltage DPFE BN/LG and GR/RD wire. Post.

Have you reached out to the tuner to see if the EGR being disabled inside the tune could have something to do with this?

The P1000 codes just means that not all of the tests have completed. Normal after disconnecting the battery or reseting the codes with a ODB2 scanner/reader.

 

[Sonic04GT]

What about this test?

If you can't find an obvious electrical problem to the DPFE sensor, replacing it is a reasonable step. Another option is to measure the voltage DPFE BN/LG and GR/RD wire. Post.

Have you reached out to the tuner to see if the EGR being disabled inside the tune could have something to do with this?

The P1000 codes just means that not all of the tests have completed. Normal after disconnecting the battery or reseting the codes with a ODB2 scanner/reader.

No I just kind of jumped the gun on that one and bought a new sensor for $45. The car has 55,000 miles and nothing electrical shows any sign of wear. Don't see why all of a sudden when the car goes for a tune it'll short. Yeah, I understand that electrical stuff goes bad out of nowhere but I took faith into account and assumed the DPFE was bad since 5 people have said it's a common issue, to the point where Ford actually extended the warranty another 2 years on it.

Now after doing further research I'm led to believe it's the tune. He said he shut the EGR off, twice according to him while he was playing with the code originally. Said I can bring the car back to him so I'm probably going to head down there soon.

Why is it not showing an engine light though? Everywhere else I read people are talking about check engine lights with the same code. I haven't seen one yet, but the code keeps reappearing.
Looks like one or 2 of the guys below have seen the same code without a MIL.
A few people have had to send the custom tune back to Diablo.

Similar issues...
http://www.diablosport.com/index.php?name=PNphpBB2&file=printview&t=9738&start=0
http://www.diablosport.com/index.php?name=PNphpBB2&file=viewtopic&p=45240
http://www.ls1tech.com/forums/generation-iii-external-engine/320985-p0405-thrown-egr-deleted.html

 

[Sonic04GT]

Backprobed with a safety pin with the ignition "ON" but engine NOT running.

I am colorblind as **** so I took pics for 100% clarification. I remember seeing 5V somewhere in my research so it looks good. Hopefully I used the multimeter correctly haha

Top pin read 5V, middle pin 0, bottom pin about 1V.

Connector
http://i295.photobucket.com/albums/mm142/thealmightyhubbard/IMAG0471.jpg

Bottom pin reading
http://i295.photobucket.com/albums/mm142/thealmightyhubbard/IMAG0473.jpg

Top pin reading
http://i295.photobucket.com/albums/mm142/thealmightyhubbard/IMAG0470.jpg

Just out of curiosity, what do you do for a living? You seem to chime into every thread with a lot of specific tech knowledge. Once again, I appreciate the help. It's more than likely the tune, I'm just curious what effects turning the EGR off will have. We don't have emissions testing in FL, my rear O2 sensors are turned off according to him, and the car has Longtubes/O/R H pipe. Some have said it'll benefit in gas mileage and low end performance, another said it could have negative effects on shortening the life of something due to temperature I believe...can't recall what. Valves maybe?

Diablo tech support says
"EGR or MDS delete will make either of those systems stop functioning." So it doesn't just shut off the sensor or anything like that. That was from a 2007 thread though.

Someone with a 2.3L claimed gains...
http://www.cadvision.com/blanchas/Ranger/egr.html

Sucks that I spent $45 on a sensor and probably would have regardless but oh well.

I put the factory sensor back in since I don't think that's it anymore. I want to try re-installing the factory tune and see if the code exists.

 

[wmburns]

From your pictures, here are the wire colors I can see.

BN/WH top
GR/RD middle
BN/LG bottom

The Ford service manual lists the DPFE normal values are .95-1.05. So 1.0 volt is right in the range. So what this tells me is the basic electronics are OK. So this means focus should be at the EGR valve, blocked EGR passage way, vacuum leak in the EGR vacuum solenoid, or corroded electrical connection at the EGR solenoid.

I'm not sure where this tread is headed. You don't really intend to fix the EGR system. In fact, you fully intended to disable it. Since you paid good $$ for a custom tune, why not go back to the tuner?

With regard to your questions about EGR. EGR is mainly a method to meet SMOG codes. EGR works by dirverting a small amout exhaust gas back through the intake. Because exhaust gas is inert, it takes up space but contributes nothing to power production. This serves to lower exhaust temperatures which in turns to lower NOX.

In a correctly working EGR system, EGR only occurs during periods of stable operation. EGR is always disabled during WOT. So in theory, EGR should not have any drivability issues.

As for me, I program computers for a living. Work on cars as a hobby.

 

[2002BLGT]

If he did delete the EGR in the tune then you should not be getting any EGR codes , did you physically block off the EGR ? Call the guy and ask him if he set the EGR scalar to 0 or 2 , from the factory its a 1 which is for the DPFE type , the older cars are 0 for a stepper type EGR , 2 disables the EGR function in the PCM , most switches are either 0 for off and 1 for on , the EGR is one of the switches that is not like this though , so he could have accidently set it to 0 thinking he was shutting it off and actually set it for the wrong type of EGR

0 is stepper type EGR
1 is DPFE type
2 shuts off EGR function

 

[Sonic04GT]

Thanks for the input guys. I am taking the car back to him tomorrow or tuesday to look at it. He's already aware of the code, but when I talked to him on the phone, he was surprised it showed up after turning it off as well.

The EGR is unaltered, in it's factory production form. So either there's a blockage as burns messaged, or the tune is playing funny games with my PCM, since I never saw the code until tuning day.

I want to gather some more information, like the 0-1-2 mentioned before going back to my tuner.

This is my post on the Diablo forum, might have a couple more details than what I've mentioned in here.

Thanks again for all of the help

 

[2002BLGT]

Thanks for the input guys. I am taking the car back to him tomorrow or tuesday to look at it. He's already aware of the code, but when I talked to him on the phone, he was surprised it showed up after turning it off as well.

The EGR is unaltered, in it's factory production form. So either there's a blockage as burns messaged, or the tune is playing funny games with my PCM, since I never saw the code until tuning day.

I want to gather some more information, like the 0-1-2 mentioned before going back to my tuner.

This is my post on the Diablo forum, might have a couple more details than what I've mentioned in here.

Thanks again for all of the help

Its more than likely just an oversight by the tuner , should have typed in 2 instead of 0 to turn that particular switch off , if the EGR is not physically blocked off then you probably have a blockage in the EGR itself or the DPFE hoses or sensor .....