2010 Sprinter crank no start + other issues

Eric Technician Blowing Rock, North Carolina Posted   Latest  
Question
Driveability
2010 Mercedes-Benz Sprinter 2500 3.0L (642.898) 5-spd (W5A380)—WD3PE7CC8A5475604
Crank No Start

Initially vehicle came in with crank no start concern, found multiple codes in system related to components on pin 46 5v reference circuit. Checked 5v reference signal at component b28/20-DPF Differential Pressure Sensor and found 1.2v. Also checked 5v reference signal at component A27/2-Viscous fan(5v present), B4/17-Fuel Rail Pressure Sensor(5v), b60/4-Exhaust back pressure sensor(1.2v). Further investigation determined that the Z7/120 5v reference circuit is at 1.2v. Z7/121 5v reference and Z7/122 5v reference circuits are operating as intended. Completely isolated Z7/120 and found 1.2v being output from CDI control unit. CDI control unit has failed internally. 

Measured independent 5v reference for engine oil sensor (B40/8) and found 2.1-2.2v at sensor.

ECM Powers and grounds checked and verified. (H7 load tested)

CDI was cloned, upon return, we were unable to program via Bluelink and had to send ecu out to be programmed, upon return vehicle condition has not changed. 

5V @ Pin 46 circuitry load tested and wiggle tested to check for short. Wire has been isolated from ECU. ECU putting out 1.0-3.1 volts cycling.

2.14v @ pin46 CDI Control unit with circuit isolated at CDI connector.

ECM Powers and grounds checked and verified. (H7 load test0 5V @ Pin 46 circuitry load tested and wiggle tested to check for short. Wire has been isolated from ECU. ECU putting out 1.0-3.1 volts cycling. 

Autologic Drivepro will NOT communicate with this vehicle. Snapon and Autel will communicate.

I have gone over this pretty thoroughly looking for shorts/opens, etc and feel comfortable that I have ruled that out as a cause. 

When cranking, when we start, we are jumping up to …FRP, we will start for 2-3 seconds and stall out. 

Any feedback or thoughts would be greatly appreciated. This vehicle has got to get moving on, and I am at the point where I am second guessing myself on everything with this.

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Shaya Mobile Technician
Jackson Township, New Jersey
Shaya Default
 

Did you disconnect every component on the 5 volt reference and test? A sensor may be internally shorted and pulling down the reference voltage

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Eric Technician
Blowing Rock, North Carolina
Eric Default
   

Initially I had checked via unplugging everything which did not result in a marked change. The pink/vt wire coming off the ecm is currently clipped about 10" outside of the ecm. It is completely isolated. To isolate a harness concern, I clipped the 5v ref lines for both the run with the DPF, EBP and MAP, as well as the oil sensor, neither made a difference to output voltage.

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Shaya Mobile Technician
Jackson Township, New Jersey
Shaya Default
 

Looks like you thoroughly checked everything. I don't have a diagram for this vehicle to know if z7/121 is referring to pin 46 and everything off that or amount circuit. But just take note that many times different 5 volt reference circuits coming out of the ECU on different pins are actually the same circuit internally, they come from the same 5 volt regulator. Therefore all the 5 volt circuits…

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Eric Technician
Blowing Rock, North Carolina
Eric Default
 

They have been, of the 3 shared references, i believe it was 120 that was down, 121 and 122 were both at 5v. The remainder of the 5v sensors have their own references from what i saw in SI.

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Reid Owner/Technician
Middleton, Wisconsin
Reid Default
 

I had one similar to you 5 years ago. Had a lot of 5 volt reference codes. Had low voltage at several sensors. Tried to isolate the wires but always had low 5 volt reference. After hours of screwing around, I found the harness that runs over the transmission to the exhaust sensors melted. All the wires in the harness were melted together. Note, you have to remove the harness material to see the…

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Matt Technical Support Specialist
Dallas, Texas
Matt Default
 

Have you gone to the ECU and cut the 5V feeds a few inches back in the harness (leave room for repair) and confirmed the 5V is not present from the controller?

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Eric Technician
Blowing Rock, North Carolina
Eric Default
 

Yes I have.

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Matt Technical Support Specialist
Dallas, Texas
Matt Default
 

With all the powers and grounds verified and the second ECU acting in the same behavior, I wander if the original ECU coding became corrupted. If the replacement ECU was "cloned" it's possible it that just transferred the issue into the replacement part.

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George Diagnostician
Burnaby, British Columbia
George Default
 

I think your going to have to source oe wiring diagrams I think your original one are leading you astray

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Reid Owner/Technician
Middleton, Wisconsin
Reid Default
 

I am pretty sure we did and there still was low 5 volt reference. If I remember correctly we were ready to order a ECM and then another sprinter with the exact year & model came in. We switch ECM and had the same problem. We orginally had thought we disconnected all five volt circuits but after ECM replacement we knew that could not be the case. I also think that Alldata wiring diagram was…

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Eric Technician
Blowing Rock, North Carolina
Eric Update
 

So, the majority of the issues have been isolated to a shorted EGR positioner. I did have a code, and I apologize for not posting a code list..flustration has had me climbing walls for more time than i care to admit on this vehicle. Thank you everyone for the replies!!

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