05 Dodge Sprinter 2.7L Turbo. P2511 EGR Signal Circuit Short to Ground

Hi folks.

2005 Dodge Sprinter 2.5L Turbo Diesel 5Cyl

P2511 - EGR Valve Signal Circuit Short to Ground - Causing Limp Home Mode (Emergency Mode in ECM)

I am feeling pretty accomplished with this one. Makes me want to stay in the diagnostic field instead of leaving it. I will update this with all the details, its late right now but I wanted to give you guys a little teaser. I couldn't find any information about this code other than people getting it deleted from the ECM at the dealer cause no one could figure it out or they would bypass the EGR system altogether. Took me about 5-6 hours over the coarse of 3 days after work.

If anyone could tell me exactly how these 3 wire Mercedes EGR valves operate internally with 3 wires that would be great just for clearing up the circuit design theory. No wiring diagram from OEM, BBB Industries or AllData showed me what I needed to see. The wiring diagrams don't even show you where the "sensor ground" is getting its ground from.

This one capture gave me everything I needed to know.
Blue: EGR Fused Power
Yellow: EGR Signal Circuit (PWM Ground Control from ECM)
Green: Ground (Connector View Diagram says "Sensor Ground")

Hey graywave! Would love to see the follow up to to this if you get the chance. Gonna guess ground circuit issue? :huh:

For giggles, I tried looking up an '05 Sprinter on BBB, and couldn't find a 2.5 turbo. But, I did find the 2.7, and this is what it showed for the EGR valve:



Not sure if this adds anything to what you already knew? Without any previous experience or knowledge of this system, I'm gonna hypothesize that there's a transistor inside the EGR valve that's controlling solenoid field strength. The signal wire is the control for the base of the transistor.

Seems weird to not have some kind of valve position feedback circuit? :silly: But, that's my idea, anyway.

Hi Tyler.

It is a 2.7L. If someone could fix that in the title that would be great I jumped the gun on this being [FIXED].

The owner is out of the country at the moment for a few weeks. I thought this was fixed and done on Monday when I added a ground to the EGR. Well took it for a test drive and all was well for a few minutes and then it went back into limp mode which disables the turbo by operating the boost pressure servo motor (waste gate). Same code for the EGR and also a CMP Sensor code and glow plug codes which come back now and then.

I decided to put on my amp clamp to the power feed to the EGR and I could duplicate those moments when the EGR fails. Looks like its shorting out and then the ECM goes into limp mode and the signal wire, maybe the controller for the signal wire? seems to stop working? I'm having him replace the EGR.

Now there are two models of this sprinter. Non OBD and OBD when looking for wiring diagrams and it seems to matter. I attached the OBD ECM Wiring. There is not one wiring diagram that shows me "where" this ground gets its ground and what other components are on this ground other than the boost pressure servo motor which I did confirm as I get the same noise at the servo motor on that ground wire.

Link to AllDATA ECM Wiring
drive.google.com/file/d/1ORYhjGDTtNon3Yd...TfV/view?usp=sharing

An OE Diagram for OBD
drive.google.com/open?id=1qaFMRpYzvU6aAN0pwACTGOrFJwZO1VMe

EGR Connector View
drive.google.com/open?id=1tdK7mNM59X21d3wP5u6sH85wsG3eK55X

The ground which jumps between the EGR and servo motor go to splice 106 which I can't find any information about.

I never thought of a transistor in the EGR. That makes more sense to me. I have been trying to figure out why there are 3 wires yet no position sensor. I also don't think I measure "current" on the signal wire, just the power wire. Never did measure the ground wire. Reason this ground wire has me complexed is because first no diagram shows me where its coming from, 2nd in a connector view, its labeled as a sensor ground which I don't think would power an EGR valve. Especially when I took my 250ma standard test light and tested the ground and saw ground voltage go up to 300+mv. To me thats a bad ground. Also tested the ground circuit with a 3157 bulb lighting 1 filament (under an amp?) and that brought the ground circuit up to over 500mv from close to 0.

So adding a new "ground" didn't fix the issue, it just bought more time for the EGR to function. As soon as I added a temporary ground before I made this thread, the EGR stayed working so I thought it was a fix. Apparently not.

Another thing to note is I was trying to follow this ground wire by seeing which harness it went into. Seem to go to the harness that leads to the ECM. Well the Cam Position Sensor Ground is Brown/Dark Green, same gauge wire and same color as the so called "sensor ground" for this EGR. The Cam sensor ground at the sensor doesn't seem to have all the same noise (when egr is operating correctly), instead the ground is fairly clean. I never did test the CMP ground at the sensor or ecm when the EGR was failing. So either this is the same ground and I just made a computer "sensor ground" grounded to the chassis when adding a new ground to the EGR or there is a separate ground for the EGR. My head was spinning a bit with this.

The image below is a zoomed out view. Yellow is current (1mv per 100ma), green is control signal. Control signal never really changes when the current ramps up. I don't have a very good shot of that so you'll have to take my word for it.

Thank you for fixing the thread title and I promise to update this when the owner gets back in town and buys the EGR. I'll run some comparison tests.