Engine shuts off intermittently, codes P0628, P1652, P1652 and P0628

Tiny
SIXTY6GTO
  • MEMBER
  • 2004 DODGE RAM
  • 5.9L
  • 6 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
I have the truck listed above with a Turbo Diesel Cummins 5.9L. The truck runs and idles fine and may shut off unexpectedly for no reason intermittently. The fuel pump was changed with an OEM part from the dealer, but still happening. Check engine light remains off while engine is running, but it has four codes stored in the computer: P0628, P1652, P1652, and P0628. Two sensors have already been changed as well with no effect. Therefore, the fuel pump and two sensors have been changed with no joy. Troubleshooting for my friend and at this moment I am taking over the job. This is the information I have. I scanned for the OBD2 codes myself. See photos of sensors that have been changed. One is on the fuel rail I believe, and the other is in an engine driven pump I believe. I ran and idled the truck for 32 minutes and could not duplicate the problem. The owner is afraid to go take it for a drive and have it shut off resulting in a tow. I ran the truck back and forth down the street and could not duplicate the problem. Should I clear the codes first and try again? The codes should help pinpoint. I think it is low circuit voltage for the fuel pump. Is this common?
Sunday, March 6th, 2022 AT 6:09 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

By accident, did you write the same code twice, or were there more?

The codes do indicate a low voltage to the lift pump. However, they also indicate a short to ground at the ECM.

I attached the diagnostics for both codes below. The first pic is specific to the P1652 and pics 2 and 3 are for the P0628.

Let me know if you are comfortable performing the tests below.

Take care,

Joe

See pics below.
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Monday, March 7th, 2022 AT 6:02 PM
Tiny
SIXTY6GTO
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My scanner had a total of four codes with each of the codes listed twice. I really want to erase the codes and run the truck and see if the codes come back again since I am new to the troubleshooting process on this vehicle since other friends tried to help him troubleshoot it previously. If there is a problem the codes will surface again anyway, I feel. I think I am comfortable pretty much with these tests briefly reading them. A wiring diagram and ECM location would help.
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Wednesday, March 9th, 2022 AT 8:20 PM
Tiny
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  • MECHANIC
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Hi,

I would be happy to provide that for you. I just need to know the 8th digit in the VIN number to get the correct schematics. The engine code will either be a 6 or a C.

As far as the ECM, it's located on the lower left side (driver's side) of the engine block. That won't change. See pic below.

I will watch for your reply on the VIN.

Take care,

Joe
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Thursday, March 10th, 2022 AT 5:08 PM
Tiny
SIXTY6GTO
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  • 62 POSTS
Hi Joe,

Is the "(D25)" in the troubleshooting steps refer to a particular pin? Meaning pin D25? In the J1850 circuit? I am trying to familiarize myself with what it is telling me in the troubleshooting steps.
The VIN number 8th digit for this truck is: the Letter "C".
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Friday, March 11th, 2022 AT 7:40 PM
Tiny
JACOBANDNICKOLAS
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Hi,

Yes, it is pin 25. A letter before usually represents a connector.

I hope this helps.

Joe
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Saturday, March 12th, 2022 AT 12:01 PM
Tiny
SIXTY6GTO
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The Letter is C for the 8th digit of the VIN, can you get the schematics?

And yes, that helps clear up the connector/pin question I had. Thanks
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Saturday, March 12th, 2022 AT 12:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

I should have attached that before. Sorry about that. I attached the powertrain management schematics below which are all tied into the module.

The schematics are 4 pages long. I had to cut each picture in half to make them readable for you. I did overlap them so you can follow from one to the next.

I hope this helps.

Let me know,

Joe

See pics below.
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Saturday, March 12th, 2022 AT 4:06 PM
Tiny
SIXTY6GTO
  • MEMBER
  • 62 POSTS
Hi Joe,

On test 1, do they want you to see if the pin (D25)? On the ECM itself? Has a good ground? They don't want to check the harness connector that I pull off because that may be covered in step 2. Step 1 is just to check to see if pin 25 on the ECM has less than 10 ohms to the battery negative which means it has a good ground as it should?
I am just making sure that they want me to probe the ECM connection area on the ECM and not the plugs (connectors) I remove which will be connected to the harness.
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Friday, March 18th, 2022 AT 11:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Yep, you are correct. I read through the directions again, and first, they want to confirm the ECM is working properly. Then, you will check the wiring by checking at the connector.

It sounds like you are moving along. Let me know if I can help in any way.

Take care,

Joe
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Saturday, March 19th, 2022 AT 6:18 PM
Tiny
SIXTY6GTO
  • MEMBER
  • 62 POSTS
I checked the ECM this weekend and there are two connectors on the ECM. They both have the same number of pins and the connecter pictured which is on the left or forward most side read 64 k Ohms to the negative battery terminal at pin #25. The other connector to the right read infinity at pin # 25. They were both neither less than 10 ohms. It was hard for me to determine which connector was "D" in the field, but I came up with these values and determined that the ECM is bad. What are your thoughts and any suggestion where to purchase a remanufactured ECM and steps to undertake when replacing the ECM if the re manufacturer already programmed it to the VIN and Engine valve cover codes etc. See attached photo of the ECM and zoom in on the left forward most connection point where I read the 64k ohms.
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Monday, March 21st, 2022 AT 9:51 PM
Tiny
JACOBANDNICKOLAS
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Hi,

It sounds like you are correct. As far as a replacement, I have personally purchased remanufactured ones online. They were plug-and-play units and honestly, I have had no issues with any of them. With a Chrysler, it seems most important that they have the original part number. They never requested my VIN, but it may be different on a Cummins.

Here is the site I used:

https://www.carcomputerexchange.com/

Neither do I nor this site have anything to do with the webpage I provided. I don't want you to think I'm trying to sell you anything. LOL, I'm not. However, it may be a good starting point for you. The one I purchased was not too expensive, and all I did was unbolt the old and install the new. The truck started right up, and I've driven it since. (Approximately 2 years now).

Let me know if this helps or if you have other questions.

Take care,

Joe
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Tuesday, March 22nd, 2022 AT 5:40 PM
Tiny
SIXTY6GTO
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Thank you, Joe!
I will see what my friend the owner wants to do. I feel better knowing you had a good result with this online provider. I will keep you posted.
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Tuesday, March 22nd, 2022 AT 7:32 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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You are very welcome. I hope you have the same luck as I have. The site I provided is where I got mine, but there are others as well.

When you have a chance, let me know how things are going for you.

Take care,

Joe
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Tuesday, March 22nd, 2022 AT 8:00 PM

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