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NHTSA expands Bosch CP4 fuel pump investigation, millions of vehicles affected


If you are familiar with heavy-duty diesel engines, then you are all too aware of the Bosch CP4 fuel pump, which has led to catastrophic engine failures in Ram, GM and even Ford heavy-duty trucks.

This key issue seems to be that our diesel fuel in the U.S. doesn’t have the same lubricity as diesel fuel used in Europe, causing wear between the cam and roller and generating small metal shavings that could be released into the fuel system.

The release of these metal shavings into the fuel system can cause catastrophic failure.

Probe expanded?

According to CarComplaints.com, the original CP4 failure investigation included 2019-2020 Ram 2500, Ram 3500, Ram 4500 and Ram 5500 trucks equipped with 6.7-liter Cummins engines.

With such a checkered history, the NHTSA Office of Defects Investigation has decided to expand its safety probe to include any automakers who have installed the CP4 fuel pump.

The upgraded probe now includes the 2014-2022 Ram 1500 trucks as well as 2021-22 Jeep Gladiator, 2014-20 Jeep Grand Cherokee and 2020-22 Jeep Wrangler vehicles. They are also looking at 2014-18 BMW 328D, 2014-16 BMW 535D and 2015-17 BMW X3 vehicles.

A recent AutoNews.com report says the CP4 fuel pump will be looked at again, and any vehicle with it – including many trucks and SUVs – could be recalled.

The Bosch CP4 fuel pump has been a hot topic of conversation, with a multitude of lawsuits and complaints connected to it.

What if your vehicle has the Bosch CP4 fuel pump?

If you have a vehicle with the Bosch CP4 fuel pump, you do have some options – you know, other than waiting for a lawsuit to be ruled on. GM and Ram trucks can be retrofitted with the Bosch CP3. Ford trucks can opt for a CP4.2 bypass kit from S&S Diesel Motorsport, and there is now a retrofit option here as well.

Another option to prevent failure is using an additive like LX4 Lubricity Extreme to help increase lubrication and prevent the metal shavings from forming.

The bottom line

While we generally have an overly litigious society, these Bosch CP4 fuel pump lawsuits have legs with many owners reporting upwards of $10k in damages. Then there’s the issue of whether some automakers knew of the problem and went forward with using the fuel pump anyway.

With at least seven active suits, spanning several states, a final resolution could take some time.

Tim Esterdahl

Automotive Journalist Tim Esterdahl has been a lover of trucks and SUVs for years. He has covered the industry since 2011 and has pieces in many national magazines and newspapers. In his spare time, he is often found tinkering on his '62 C10 pickup, playing golf, going hunting and hanging out with his wife and kids in Nebraska.

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  1. Michael Colburn April 21, 2023

    Since 2007 when USEPA mandated ULSD the below question has never been answered

    The ASTM HFRR test is an abortion. A complete joke. Where does the HFRR test duplicate pressure like a modern-day diesel fuel system? Bosch CP4 pump failures prove the current ASTM lubricity test is a complete abomination

    I would like to ask you a question, in all your years of experience, has anyone ever defined for you the meaning of “Diesel Fuel Lubricity”? Beyond just the words? I have looked high and low and from here to there for even a technical definition by anybody and I have found nothing. Sulfur has no lubricating properties whatsoever.

    Or put another way. Outside of the ultra-low sulfur diesel fuel excuse. Do you know what causes diesel fuel to have poor lubricity? What is causal mechanism in the fuel that is causing the diesel fuel the poor lubricity problem?

  2. John Glenna May 10, 2023

    2012 F350 Powerstoke, and spent over 10,000 for complete new Fuel system due to CP4 failure, I would like to be on the list to get updates as to when Ford could reimburse us or some type of compensation.

  3. .Mark Schnautz June 5, 2023

    Then why did Marathon terminals install lubricity tanks at the terminals when they switched to UL sulfur diesel? Sulfur is a lubricant for fuel pumps.

  4. Dan Pulley June 10, 2023

    I have a 2022 Ford F350 6.7 with 55000 miles on it and 2 months ago the high pressure fuel pump went out. Took it to the dealership was told not covered under warranty. Got it back back 2 weeks ago and it started flashing up on the display reduced engine power and would cut off. Took it back to dealership. They have had it going on 2 weeks and told us they don’t know what is going on and they don’t know how to fix it.

  5. David Holloway July 19, 2023

    My 2016 f-250 with 70K miles is in the shop for the second time in the last 3 years, the first one cost over $12,000 and when I pick it up this Friday, it will cost over $18,000. CP)4 pump

    1. Don September 5, 2023

      I got 2016 F250 , 156,000 and cp4 failure yesterday.

  6. Jerry September 26, 2023

    Yup. My cp4 grenaded and trashed my entire fuel system over the weekend on our way to family vacation. EVERYTHING in the fuel system has to be replaced. $14,000 repair bill. thanks Bosch.


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