The Big Four Failure Modes
Ram 2500 and 3500 trucks built around the 6.7L Cummins I-6 have generated more warranty claims than anyone at Stellantis wants to admit. The four failure patterns we see repeatedly in California:
1. Bosch CP4.2 High-Pressure Fuel Pump
The CP4.2 pump, used on 2019 through current 6.7L Cummins builds as part of the emissions and fuel delivery system, has been tied to metal-on-metal wear events that grind the cam lobe and pump head. Shrapnel enters the fuel system and contaminates injectors, rails, the fuel tank, and every fuel line. The entire high-pressure system must be replaced. A vehicle that has experienced a CP4 failure once is at ongoing risk for residual contamination failures. Pattern evidence on CP4 failures supports a strong willfulness argument for civil penalties under Civil Code 1794(c).
2. EGR Cooler Cracks
EGR coolers on the 6.7 crack internally, allowing coolant into the EGR flow and into the intake. Symptoms: white exhaust smoke, sweet coolant smell, overheating, coolant consumption without external leaks, and warning codes related to EGR. Replacement EGR coolers sometimes fail again within a year. Repeat EGR repairs are the backbone of many Ram Cummins lemon claims.
3. Turbo and Actuator Failures
The Holset variable geometry turbo on the Cummins uses an actuator that can seize from soot loading, triggering power loss and throttle cut. Replacement of the actuator or the entire turbo assembly is the dealer's standard fix. When the issue returns within a short interval, a Song-Beverly repair pattern is established.
4. DPF and Regen
Diesel particulate filter regeneration problems mirror those on other diesels: failed regens, manual forced regens at the dealer, DPF pressure sensor faults, and eventual DPF replacement. Each dealer visit counts toward the 4-attempt presumption, and extended DPF replacement waits count toward the 30-day out-of-service branch.
The Warranty Structure for Ram Cummins
- Basic: 3 years or 36,000 miles bumper-to-bumper.
- Powertrain: 5 years or 100,000 miles on most Cummins-equipped Rams.
- Diesel engine long-block: 5 years or 100,000 miles for most years.
- Federal emissions and California ARB emissions warranty: extend well beyond 3/36 for specified components, including fuel system and catalyst components.
Fourth CP4 Visit? EGR Cooler Round Two?
Pattern of Cummins emissions or fuel-system repairs is the exact profile Song-Beverly was written to address. Ram pays your attorney fees under Civil Code 1794(d).
Submit Your Case Call (310) 598-9614
Heavy-Duty Coverage Considerations
Ram 2500 trucks are often under 10,000 pounds GVWR and fall inside Civil Code 1793.22(e)(2)'s small-fleet coverage. Ram 3500 trucks are typically above 10,000 pounds. For trucks outside the 10,000 GVWR threshold, claims proceed under Magnuson-Moss and CLRA where applicable. An attorney can confirm coverage from your door jamb GVWR sticker and registration.
Evidence That Drives Settlement
- Every Ram repair order with Cummins-related customer concerns.
- CP4 failure diagnosis, injector replacement records, and full fuel system repair invoices.
- Photos of DPF regen screens, warning lights, and CEL events.
- Rental equipment expenses when the truck was out of service on a job.
- Stellantis/FCA technical service bulletins related to Cummins emissions repairs.
- Loss of revenue documentation for small-business owners.
Remedies
- Buyback: full price, taxes, DMV, finance, incidental damages, minus mileage offset.
- Replacement: comparable Cummins-equipped Ram.
- Cash-and-keep: when ongoing repair risk is manageable and value has been impaired.
- Civil penalty: up to 2x actual damages.
- Attorney fees: paid by Stellantis/FCA under Civil Code 1794(d).
Related Reading
Frequently Asked Questions
Are deletes or tunes a problem?
Yes. Aftermarket deletes of emissions equipment can defeat warranty claims and may create independent CARB exposure. Do not delete a work truck.
What about my 2500 HO with the high-output Cummins?
HO configurations often exceed 10,000 pounds GVWR. Coverage analysis depends on registration and business use.
Is fuel contamination a defense?
FCA sometimes blames bad diesel. Fuel receipts and CP4 metallurgical analysis rebut that defense.