Failure mode - Cummins 6.7L ISB Diesel (Ram HD, 2019+ generation)

Grid heater bolt and relay failures (2019+ 6.7)

Reliability tier: verified - verify before ordering, see /disclosure/

Symptoms

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

Compare with the other causes of the same sign on this engine: hard start, long crank or no-start (3 causes) · white smoke from the exhaust (3 causes) · ticking, knocking, rattle or whine (3 causes)

Root cause

The intake grid heater's high-current terminal nut and bolt sit inside the intake after the turbo; heat and arcing wear them until they break off and are drawn into a cylinder, the same failure documented on the 2007.5-2018 engine. Separately, the solid state heater grid relay on 2021-2023 trucks can short with the ignition on or off and start a fire (recalls 21V-163, 21V-798, 23V-060).

Diagnosis

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

Fixes

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

grid-heater - more than one option: Banks Power Billet Heater Kit, 1500W (2019-2024 Ram 6.7L Cummins; requires Monster-Ram installed) (upgrade option), Banks Power Billet Heater Kit, 750W (2019-2024 Ram 6.7L Cummins; requires Monster-Ram installed) (upgrade option), Banks Power Dual Heater Upgrade Kit (2019-2024 Ram 6.7L Cummins; requires Triple-Heat-capable Monster-Ram) (upgrade option), Banks Power Monster-Ram Intake & Killer Grid Heater Upgrade (2019-2024 Ram 2500/3500 pickup, 6.7L Cummins) (upgrade option), Banks Power Monster-Ram Intake & Killer Grid Heater Upgrade, Chassis Cab (2019-2024 Ram 3500/4500/5500, 6.7L Cummins) (upgrade option)
Killer Grid Heater Upgrade Kit (BD Diesel 1041520, 2007.5-2024 Ram 6.7L Cummins)

Prevalence

common