Symptoms · 6.7 Cummins 2019+

6.7 Cummins 2019+: hard start, long crank or no-start

3 documented failures on this engine list this among their signs. They are ordered from the most widespread down. Each one shows the signs in its record's own words, how to tell it from the others, the usual fix and any recall or bulletin.

CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7) Very common · 66 complaints · 3 recall/bulletins
Grid heater bolt and relay failures (2019+ 6.7) Common · 22 complaints · 3 recall/bulletins
In-tank lift pump failures (2019+ 6.7) Common

Not sure which engine you have, or want the recalls for your exact truck? Check your VIN: it names the engine and lists the campaigns for that model year. Whether a recall is still open on your VIN: nhtsa.gov/recalls.

1 CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7)

verified How widespread: Very common 66 NHTSA owner complaints match it, out of 318 checked

How it shows up

sudden loss of power and stall, often with no warning or after a 'Service Exhaust System' type message; may not restart
codes P0087 (rail pressure too low), P008A (low-pressure side too low), P0201-P0206 (injector circuits); engine will not start

Its other signs

metal debris in the fuel filters once the pump has come apart

How to tell it apart

check the VIN for recall 21V-880 / Y78 first
on a stall or no-start, inspect the fuel filters for metal before replacing parts
a CP3.3 pump looks and sounds different from the CP4; bulletin 14-008-22 explains the identification differences

Usual fix

recall Y78: CP3.3-style pump, PCM update and fuel system parts as needed, free at a Ram dealer

Recalls and bulletins

21V-880 18-099-22 / 18-054-21 14-008-22

Root cause, parts and sources →

2 Grid heater bolt and relay failures (2019+ 6.7)

verified How widespread: Common 22 NHTSA owner complaints match it, out of 318 checked

How it shows up

code P2609 (intake air heater circuit) and P0542; long crank and white smoke in cold weather

Its other signs

knocking at speed after the heater's terminal nut or bolt breaks off and is pulled into a cylinder (owners most often name cylinder 6)
smoke or fire from the heater grid relay on 2021-2023 trucks (recalled)

How to tell it apart

take P2609 seriously: inspect the heater grid terminal hardware before replacing the relay alone
check the VIN for the relay recalls on 2021-2023 trucks
verify relay operation and voltage drop at the studs at key-on

Usual fix

repair the relay/circuit; reseal or replace the grid heater assembly (retention bolts with the update kit)

Recalls and bulletins

23V-060 21V-798 21V-163

Root cause, parts and sources →

3 In-tank lift pump failures (2019+ 6.7)

verified How widespread: Common

How it shows up

fuel pressure sag under load on a gauge; hard hot starts; injector rattle from starvation

Its other signs

CP3 inlet contamination when the pump sheds debris

How to tell it apart

fuel pressure gauge at the CP3 inlet - log hot and under load
inspect the water-in-fuel filter element and drain schedule

Usual fix

replace the lift pump/module and the fuel filter; consider a gauge if not fitted

Root cause, parts and sources →

Other symptoms on the 6.7 Cummins 2019+

Loss of power, limp mode or derate White smoke from the exhaust Losing coolant Ticking, knocking, rattle or whine DEF, DPF and regeneration warnings

Everything on the 6.7 Cummins 2019+Its recalls and bulletins

Order: how widespread each failure is in its record (near-universal, very common, common, occasional, rare), then the number of NHTSA owner complaints that match its keywords. Complaint counts are keyword matches, not a manual review of each complaint. A symptom listed here means the failure is documented with that sign; it is not a diagnosis of your truck. Tiers: verified, aggregated, contested, data-gap. How we tier and source facts.