Cp4 buzzing noise

[Pjc87]

I have a 2020 Ram 5500 6.7 Cummins with a build date of 8/20
It has the revised cp4 injection pump with the big dimple on the pump.
Ever since we got this truck it makes a loud buzzing noise that cuts in and out and it’s super annoying.
I read the tsb pointing out the 2 different pumps one is asymmetrical and the updated pump is symmetrical.
It says on the tsb make sure the truck is calibrated for the correct pump otherwise you will hear noise from the injection pump.
So I thought since this truck was built in august which is right around the time they started to install the updated pumps, what if this truck was calibrated for the old style asymmetrical pump and not the uodated symmetrical.
So I took it to my local dealer and asked them to check and see if it was calibrated for the symmetrical pump and the service writer tells me they have no way of checking that.
I find that very hard to believe, she said they plugged into the truck and gave it the latest updates and that they heard no more noises from the pump.
I pick up the truck and it’s still making the same
Exact buzzing noise that cuts in and out.
So how do I proceed forward and get them to understand that I’m simply just asking them to check and see which pump this truck is calibrated too?
And has anyone else had this buzzing sound coming from the updated cp4 pump?

 

[Brutal_HO]

Welcome to HDRams.

You sure it's the pump and not something else like EGR?

Since you don't say if you're a first time CTD owner, have you compared it to any other trucks to see if what you're hearing is normal?

Ask the dealer for a "Scan Report." it will show all the code levels on all the modules. I can't put my finder on it right now, but I believe the 4th digit in the PCM flash part# is different between the Asymm and Symm pumps.

My dealer gave me a scan report when asked with no pushback. It included two pages of module flash part #'s and the full details of every set code.

 

[Pjc87]

We bought two 2020 ram 5500’s.
One has a build date of 8/20
And the other has a build date of 9/20
The truck with the build date of 9/20 has the same dimple cp4 pump and it does not have this annoying rattle that the 8/20 truck has.
It sure sounds like it’s coming from the injection pump too me.
I will take it to the dealer again and ask for a scan report.
And ask them for the 3rd time to verify this truck is calibrated to run with a updated symmetrical cp4 pump.

 

[Brutal_HO]

@RamCares can escalate a case if you're not getting any satisfaction with the dealer.

 

[RamCares]

We bought two 2020 ram 5500’s.
One has a build date of 8/20
And the other has a build date of 9/20
The truck with the build date of 9/20 has the same dimple cp4 pump and it does not have this annoying rattle that the 8/20 truck has.
It sure sounds like it’s coming from the injection pump too me.
I will take it to the dealer again and ask for a scan report.
And ask them for the 3rd time to verify this truck is calibrated to run with a updated symmetrical cp4 pump.

Hi PJc87, if would like assistance while working with your dealer on this please don't hesitate to send us a PM with your VIN and mileage. We would be happy to assist you along the way.

Michelle
Ram Cares

 

[JJC72]

my truck makes the same noise, build date of 10/20 with large dimple pump. What was your final resolution if any?

Thanks

 

[Bucky57]

I have a 2020 with the same problem, I took it to the dealer and they said it’s “normal” the buzzing is really annoying and is definitely coming from the cp4. Hope there’s some kind of fix for it.

 

[Epsilon Plus]

The correct fix for it is a recall and switch to the CP-ISB21S3 that Stellantis is dragging their feet over.

There is only one very vague indication that they are planning to do anything about it that would properly correct the problem. See this mega thread for details:

CP4 to CP-ISB21S3 (revised CP3) change for 2021 6.7L Diesel Trucks -- Merged Threads

So for those that haven’t bought yet, get the 2021. The 2021 (verified just a little while ago) has the CP3. So no need to deal with a recall etc. [MOD EDIT: Any complaints or rants about the CP4 may be messaged in one of the other three or four threads along those same lines or the following...

hdrams.com

 

[RAMbot]

New to this forum and new to a 2021 RAM 3500. I ordered in May and picked up 6/25/2021. I have the same noise and I don't have the CP4, it is the new pump. I cant hear it inside the cab but noticed it as soon as I got home. I also have the Aisin 3-4 shift squeak under load. Never had either issue with the previous 2 RAM Cummins, 2014 and 2018. Will be going back to the dealership as soon as I am done with the rest of the shake down.

 

[Dmacmilitant]

My pump failed and was replaced with the updated CP4 and it buzzed when I got it back. The dealer that did the work said it was fine. I went to a different dealership that found the software update hadn't been performed for the new style pump. They did the update and now it's silent. This took the second dealership all of 3 hours to verify, diagnose, and fix. Had my truck back by 1:00pm the same day. Exceklw t service from McConnell Dodge in Healdsburg, CA.

 

[Pjc87]

My cp4 is still rattling away, they did a scan report and handed it to me and according to their scan report it’s calibrated correctly.
So I guess it’s just a noisy pump.
Still nervous it’s gonna explode any minute with how much noise it makes.