Diesel Trouble Codes

P042E — Exhaust Gas Recirculation Control Stuck Open (6.7 Cummins (SCR / DEF))

Exhaust Gas Recirculation Control Stuck Open

Updated September 2, 2026

What it means

The EGR control circuit reports the valve stuck in the open position on the 6.7L Cummins SCR/DEF 2013–present. This platform has an EGR valve + cooler, DOC/DPF/SCR+DEF, VGT HE300VG with electric actuator+position sensor, CP3 2013-2018 & 2021+, CP4.2 2019-2020 only, in-tank lift pump, rail pressure sensor, FCA/MPROP, mechanical rail pressure relief valve, solenoid common-rail injectors, grid heater, no glow plugs, mechanical wax thermostat, gear-driven timing, MAP primary with MAF for EGR/emissions.1

Most likely causes

  1. EGR valve stuck open mechanically due to carbon buildup / soot fouling in valve and cooler passages — Carbon accumulation can hold the valve off its seat, keeping EGR flow higher than commanded. Typical on 6.7L Cummins 2013–present with EGR valve+cooler present.1
  2. EGR valve position sensor / actuator feedback error causing the ECM to infer stuck open — The ECM monitors commanded vs. actual EGR position. A faulty position sensor or wiring can make the control circuit appear stuck open even if the valve moves. Platform uses EGR valve+cooler and MAP primary with MAF for EGR/emissions.1
  3. EGR control circuit electrical fault — wiring, connector corrosion, or ECM driver issue — Open/short in the EGR valve control wiring or poor connector contact can set a stuck-open diagnostic. Affected systems: EGR on 6.7 Cummins SCR/DEF.1
  4. Excessive EGR flow due to intake/EGR restriction or cooler internal failure affecting flow measurement — Restriction or internal cooler breach can alter measured EGR flow relative to command, contributing to P0402-type excessive flow conditions on this platform.2

How to diagnose

  1. Verify freeze frame and confirm P042E is active on 6.7L Cummins SCR/DEF 2013–present with EGR hardware present.
  2. Inspect EGR valve and cooler for carbon/soot fouling and mechanical binding; check valve pintle movement and seat condition.
  3. Check EGR valve position sensor signal and actuator command vs. actual with scan tool; compare to MAP/MAF-based EGR flow expectations.
  4. Inspect EGR control wiring and connectors for corrosion, chafing, or poor pin contact; perform pin drag and continuity tests per service info.
  5. Review related EGR flow codes such as P0401 insufficient flow and P0402 excessive flow for pattern clues on this platform.

Parts and tools you may need

Rough cost and difficulty

Parts and labor vary by model year and calibration; diagnostic time is typically 1–2 hours. EGR valve replacement or cleaning costs vary widely. Obtain quotes for the specific Ram 2500/3500/3500-5500 cab-chassis year.

When to see a pro

If the EGR valve is seized, the intake/EGR passages are heavily carboned, or wiring/ECM driver faults are suspected, have a qualified diesel technician perform inspection and repair. Do not attempt high-pressure fuel or turbo work without proper training.

Sources

  1. Curated DTC seed — 6.7 Cummins (SCR / DEF) (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 6.7 Cummins (SCR / DEF) (curated) ↩︎

Watch a repair

Third-party videos, not ours — for illustration. Confirm anything against the factory service information for your truck.

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2019 6.7 Powerstroke EGR Maintenance: The Problem With Carbon Build-Up — Dave's Auto Center · 170K views