In 2021, Ram returned to the trusted Bosch CP3 fuel pump after widespread CP4 failures in 2019–2020 models. These newer trucks are considered more reliable overall, but they still suffer from camshaft & lifter failures, turbo actuator problems, and DEF/NOx sensor issues.
Whether it’s a Ram 2500, 3500, 4500, or 5500, the 2021+ 6.7 Cummins is a strong engine — but owners should stay on top of known issues to avoid costly downtime.
At DK Auto & Diesel Service in Magnolia, TX, we service, diagnose, and upgrade all 2021+ Cummins-powered Rams.
Common 2021–Present 6.7 Cummins Problems & Symptoms
1. Camshaft & Lifter Failures
• Symptoms: ticking noise at idle, misfires, reduced power, metal shavings in oil
• Causes: lifter roller seizure damaging cam lobes; worsened by high idle hours and towing loads
• Fixes: camshaft & lifter replacement, valvetrain inspection, preventive oil service with high-quality filters
2. DEF System & NOx Sensor Failures
• Symptoms: DEF warning lights, limp mode, poor mileage
• Causes: failed DEF heaters/pumps, NOx sensors losing accuracy
• Fixes: DEF heater/pump replacement, updated NOx sensors, system diagnostics
3. Turbocharger Actuator Issues
• Symptoms: low boost, poor towing performance, actuator fault codes
• Causes: actuator motor failure or sticking VGT vanes
• Fixes: turbo actuator replacement, turbo service or upgrade
4. Injector Wear
• Symptoms: rough idle, hard starting, excessive smoke, poor fuel economy
• Causes: high-pressure common-rail injector nozzle wear
• Fixes: injector testing & replacement, fuel filtration upgrades
5. Transmission Stress (68RFE & Aisin AS69RC)
• Symptoms: slipping, overheating, or harsh shifts under heavy load
• Causes: torque exceeding stock clutch design
• Fixes: transmission rebuilds, HD torque converter upgrades, valve body improvements
How DK Auto & Diesel Fixes the 2021+ 6.7 Cummins
- Camshaft & lifter replacements (valvetrain tick repairs)
- DEF/NOx system repairs & updates
- Turbo actuator repairs & turbo rebuilds
- Injector testing & replacements
- Heavy-duty transmission rebuilds for 68RFE & Aisin trucks
- Preventive maintenance for work, fleet, and tow trucks
Schedule Your 2021+ Cummins Diagnostic in Magnolia, TX
If your 2021+ Ram 6.7 Cummins is ticking, showing DEF errors, or losing boost, trust DK Auto & Diesel Service for expert service and upgrades.
Serving Magnolia, Montgomery, Conroe, The Woodlands, Tomball, Willis, and Spring.
Book a Cummins Diagnostic Today
FAQ About the 2021–Present Cummins
Is the 2021+ Cummins reliable?
- Yes — the return to the CP3 fuel pump improved reliability. But cam & lifter failures remain a known weak point.
How long will these trucks last?
- With proper care, 350k+ miles is achievable, though valvetrain service may be required earlier.
What’s the most common issue?
- Camshaft & lifter wear and DEF/NOx sensor problems are the leading causes of repairs.
