The National Highway Traffic Safety Administration has opened an investigation into nearly 605,000 heavy-duty Ram trucks. A report from the regulator’s Office of Defects Investigation has tabulated 22 complaints from the 2019 and 2020 model years, all of which use 6.7-liter Cummins turbo diesel engines, spurring the NHTSA to launch a formal investigation. Complaints revolve around loss of motive power, with most incidents occurring above 25 mph and resulting in the “permanent disablement of the vehicle.”
While the public was not made aware of the investigation until Monday, the agency launched its probe last Thursday on October 14th. The goal will be to establish how widespread the presumed defect is, what exactly caused it, and any potential safety hazards relating to the issue. Some headway has already been made, however.
Back in 2019, Fiat Chrysler Automobiles (now Stellantis) issued Warranty Bulletin D-19-02 to dealers. The memo requested stores participate in a campaign to “collect, monitor and correct quality issues” on certain MY 2018-2020 Ram trucks equipped with the 6.7-liter Cummins. The NHTSA’s action summary states that this resulted in FCA and an unnamed supplier collecting and inspecting high-pressure fuel pumps.
Vehicles under suspicion include all Ram 2500, 3500, 4500, and 5500 HD pickups from the 2019-2020 MY. The NHTSA plans on looking into the trucks to determine whether or not it needs to press Stellantis to launch a recall. That means asking the manufacturer to give its take on the situation while it compiles warranty claims, injury reports, and whatever FCA previously had on those suspect fuel pumps.
Regulators have been incredibly hard on diesel vehicles ever since Volkswagen’s emissions scandal upended the industry in 2015. While a part of me wants to believe the NHTSA just has it out for Ram’s HD lineup (since a few have asked), it seems far more plausible that this was a standard, shrug-your-shoulders defect. Selective environmental regulations have made diesels cost more as they’ve gradually amassed a bevy of pollutant controlling hardware while also complicating powertrains to a point that has lessened their overall effectiveness. But the impact this has had on their reliability is less obvious and may have nothing to do with a bunch of subpar fuel pumps.
Let’s face it, U.S. regulators haven’t been shy about hitting manufacturers with emissions-focused recalls backed by the Environmental Protection Agency and/or California Air Resources Board in the past. If they wanted to chide Cummins or FCA/Stellantis over pollution, they could have done so overtly.
Stellantis has said it plans on cooperating with the NHTSA fully, launching an investigation of its own for good measure. So we should have some answers soon, including the name of the supplier. In the meantime, you might want to keep a closer eye on how your HD Ram is running if it falls under the purview of the investigation.
[Image: Stellantis]
Become a TTAC insider. Get the latest news, features, TTAC takes, and everything else that gets to the truth about cars first by subscribing to our newsletter.

So these get up to 25 mph and the engine bricks itself?
Well, I guess that’s one way to keep my rear view mirror from being filled up with RAAAAMMMMMMMMMMMMMMMMM grille.
The diesel engines in these HD trucks are probably the most complicated things you can buy south of a Bugatti.
I’m an HD advocate when it comes to frequent towing but now that the Ford 7.3L offers a 20,000lb gooseneck/5th wheel rating I’d only go for the diesel if I was a commercial operator.
And those old V10 fords and Dodges are worth almost nothing due to their hideous economy. Same will happen to the new 7.3, I predict.
I just looked up Ram HD V10 prices and we must have different definitions of “worth almost nothing”.
Plus how are Ford 6.4L diesel resale values?
I’m thinking he hasn’t looked recently. Even before the recent run up in car prices the values on used gas HD trucks has been trending up. I have a feeling emissions issues is a big reason for it. A gas 3/4 ton used to have a value on par or maybe worth 10-12% more then a 1/2 ton on the used market. Over the last 4-5 years that is more like 20-30% more.
I can’t imagine towing recreationally and buying one of today’s diesels. They aren’t very reliable, they’re tuned for bragging rights instead of durability or heat management, and on top of it all they’re still a bit stinky. (And I wouldn’t be shocked to learn that their emissions are fraudulent, either.) I’ll second ajla that if I were going to tow a heavy trailer around for hobby reasons, I’d be getting a 7.3 Super Duty. (Though in fairness the GM 6.6 isn’t a bad choice either.)
I have noticed that modern diesels have traded the old strong skunky smoky smell for the new emissions controlled ones that under high loads make a much milder hint of chlorine/ ammonia smell.
thats because sulfur levels are reduced and onboard urea
I mean the power when they work is incredible. If you never tried it you would be happy with gas but modern turbo diesels pull really hard (gas could too if were honest and wanted it too). I haven’t been in the latest batch but 10 years ago pulling a travel trailer with a power stroke or Cummins was amazing compared to the gas jobs Ive used most of my life.
But I’m with you I couldn’t justify it either recommended the same to my inlaws and they ordered a 6.6 Silverado. I like the 6.4 rams I’ve driven they are supposedly less torque y down low but I can’t find a chart to confirm that.
I know one RV writer recently had both a Ford and Ram go into limp home modes on him while remote camping out west. Driving to a service center from the middle of nowhere in AZ and under 35 mph must be a real pain in the ass.
“10 years ago pulling a travel trailer with a power stroke or Cummins was amazing compared to the gas jobs Ive used most of my life.”
Modern HD gas engines are a lot better than the ones of 10 years ago, let alone older ones.
I’m convinced a lot of people order $10K diesel engines nowadays simply because they don’t like the sound of the higher revs of the gasser or think it’s bad for the engine. It’s their money, but seems like a waste to me.
I think it will be interesting to see how my inlaws 6.6 does. They will be towing around 9k worth of 5th wheel. I have a few friends that tow heavy with pickups for a living and I know they all still buy diesel so I assume there is something they still need. One guy I noticed did drop the diesel for his newest 2500 Ram, that he uses to tow around a giant chipper and bobcats etc. but his partner went with a cummins to haul their excavator and dump trailer.
If you’re using the truck commercially, then the fuel economy over a couple of years is enough to pay for the diesel and for its increased maintenance costs. But I bet a lot of the commercial operators would appreciate a tune that would sacrifice a bit of the bragging rights for the sake of heat management. if I were using one of these as a job tool, I’d get EGT and oil temp gauges and watch them very carefully.
The three appeals of diesel I can see are:
1. Lower revs. This is probably the biggest one. Like you wrote alot of people freak out over 4k RPMs.
2. Easier refuelling when towing because diesel pumps can often be found on their own island.
3. Unladen highway fuel economy.
@dal20402 – a diesel HD is worth it if you plan to pull heavy for long periods of time. It makes zero sense for a once a month RV tow to the lake.
The commercial fleets in my area stay away from diesels because pickups don’t last long enough to reach a return on investment. If they require heavy hauling/pulling then they go straight to light HD commercial trucks.
I have a 2015 Duramax and 2014 4Runner. The only time I smell any difference is at the fuel pump or during a regen. The Duramax gets better mileage unladen. I tow a bumper pull 7500lb camper 2 to 3 times a year. I replaced my gas burner because it struggled to hold highway speeds while the oil burner cruises easily without downshifting for every slight grade. To each their own.
“I replaced my gas burner because it struggled to hold highway speeds”
Was your gas burner from the 1980s?
I could (if I wished) maintain 90 mph pulling 7500 lb with my F350 6.2L. The GM 6.6, Ram 6.4, and Ford 7.3 are all more powerful than my truck. It does downshift on grades but that is expected and not a concern to me.
“Permanent disablement” sounds interesting. I would like to hear details (the report doesn’t seem to include details of what exactly happened).
The heavy duty diesels used to be the most reliable engines you could buy. Powerful, efficient, reliable and if left unmodified reasonably clean. The RAM 6.0 was good for hundreds of thousands of miles. But now the RAM is saddled with expensive and unreelable emissions garbage like all the other once good engines. Too bad common sense could not have played a middle ground between modified coal rollers and climate change shysters.
These emissions controls aren’t primarily due to climate change, they are to deal with particulates and nitrogen oxide. I’m surprised you thought they were.
And why the concern for particulates and nitrogen oxides? I’m surprised you thought they weren’t related.
Related to global warming? Diesel particulates cause cancer and other lung problems. They aren’t related to global warming. NO, while a greenhouse gas, is regulated because it causes smog.
Diesels used to be low power, low revving, high torque engines that didn’t go fast, stunk, but could go forever. The true heavy duty ones still are. In the light truck market though, it’s all one big measuring contest to see who has the most hp and can get to starbucks quicker. Bonus points if you completely screw up the fuel settings to make it roll coal, super cool brah! Gotta make them super complicated to squeeze out as many HP as possible for the look at me crowd but also can’t offend the tree huggers delicate noses. Reliability = reduced
Spoken like someone who still dumps his used motor oil down the well.
It’s the only true way to own the libs…
Oh, so not liking coal rollers and obvious polluters but also not liking overly complicated emissions controls makes me some kind of pariah to you? Spoken like a self righteous snowflake….
toilet and a couple flushes. mebbe wipe down the bowl? good enough to throw frying oildown, right?
Not sure why the foray into emissions…don’t ALL diesels require high pressure fuel pumps? It does seem like a normal recall. The vehicle shuts down and won’t restart. As for diesel vehicles getting extra scrutiny because of the cheating scandals, well, why shouldn’t they? One reaps what they sow.
RAM seems to have hit its stride – they are thick on the streets here. And not just for the air-hauling crowd. Lots of them are outfitted for real work. Wasn’t all that long ago that Ram trucks were not very common compared to the other brands.
Agreed.
All the commentary about emissions has nothing to do with bad fuel pumps, which is a safety issue.
I think it’s more just the trend of Diesels getting less reliable is largely tied to emissions. Much like cars in the late 70’s. My Neighbor was a mechanic and for a medium duty truck dealer when the new emissions came online and man did he have horror stories, He’s now a manager but says the problems have gotten a lot better over the past 5-6 years, not as good as before but manageable.
This morning, as I passed my thrid 2nd gen (94-2001) ram cummins on the highway I realized they must be one of the most common 25 year old daily drivers in existence, The other thing that strikes me is that on average they look better then they did 10 years ago. The values on these seems to have them getting restored, over the weekend I saw two in front of a MAACO getting all their trim stripped with new black premiered front fenders getting ready for paint. The issues with modern diesels mean the old ones must have some damn severe damage to be taken off the road.
There is a shop a couple blocks from my house the does truck frame repair. There are 3 vehicles that I commonly see there (because their value makes it worth while) Dodge Cummins, Jeep Wrangler, and any Toyota pickup.
This is most likely related to the Bosch CP4 injection pump that Ram used during these years. The CP4 likes to grenade itself and send metal through the entire fuel system. Starting in 2021 they went BACK to using the older CP3 injection pump.
This problem is not limited to Ram. GM and Ford have also used the CP4 on their diesels with similar issues.
Posky seems unable to write anything without throwing his usual barrelful of red herrings at us.
“Selective environmental regulations have made diesels cost more as they’ve gradually amassed a bevy of pollutant controlling hardware while also complicating powertrains to a point that has lessened their overall effectiveness. But the impact this has had on their reliability is less obvious and may have nothing to do with a bunch of subpar fuel pumps.”
Yes, it may have nothing to do with that. Give me five minutes, and I could list a thousand other things it also may have nothing to do with. You’re the supposed journalist–why don’t you tell us what it DOES have to do with? Or what, at the very least seems likely? Or just admit that, like the rest of us, you really don’t know?
This is an awful lot of words spilled over some fuel pumps crapping out for as-yet unknown reasons. But I guess the story had to be tweaked and expanded for maximum aggrievement, Posky’s stock-in-trade. How exhausting.
“Selective environmental regulations have made diesels cost more”
Even this is misleading. “Golden Age” 200-250 hp diesel engines cost $4-5000 in the 90s-early 00s, which is $7500 or so adjusted. 450 hp diesel engines costing $10K now is hardly out of line by comparison.
The lighter-duty GM 3.0L is only $1K more than the 5.3L V8. And the diesel gets a better transmission.
I still wouldn’t buy one though, unless I was leasing or only owing for 3-4 years.
“Selective environmental regulations have made diesels cost more”
I read that over the past 20 years there’s been a 95% reduction in emissions from commercial diesel trucks.
In USA or Canada diesels in light vehicles don’t tend to sell well. Pickups are the only exception.
This is how much I know about diesel pickups… -holds forefinger and thumb at 10mm gap-.
But I do know that anytime you drive more than 15 miles from home, you should have a can of this in your truck:
https://www.amazon.com/CRC-05110-Mass-Sensor-Cleaner/dp/B000J19XSA
Cummins Switched to a CP4 pump which has a high failure rate. Duramax tried this
pump and had lots of problems with it.