Diesel Trouble Codes

P042E — Exhaust Gas Recirculation Control Stuck Open — 6.4 Power Stroke

Exhaust Gas Recirculation Control Stuck Open

Updated October 15, 2026

What it means

The EGR control circuit reports the valve stuck in the open position. On the 6.4L Power Stroke, EGR hardware is EGR valve plus EGR cooler.1

Most likely causes

  1. EGR valve stuck open due to carbon buildup / mechanical binding — Valve pintle or seat carboned, preventing closure; typical EGR flow/position fault on this platform.1234
  2. EGR valve position sensor / feedback circuit fault — Position feedback out of range or implausible, causing PCM to infer stuck open; EGR control circuit range/performance is a related fault family.12
  3. EGR valve control circuit electrical fault — Wiring, connector corrosion, or driver fault causing valve to remain energized/open; EGR control circuit issues are documented for this engine.12
  4. EGR cooler bypass valve performance issue affecting EGR flow control — On 6.4L, P2457 is defined as EGR cooler bypass valve performance, not generic EGR flow low; bypass valve faults can influence EGR operation.5

How to diagnose

  1. Verify code and freeze frame; confirm P042E is present and not accompanied by other EGR or aftertreatment codes.
  2. Inspect EGR valve and passages for carbon buildup and mechanical binding; check valve pintle movement with ignition off.
  3. Check EGR valve position sensor signal and reference/return voltages; compare commanded vs. actual position data at idle and elevated engine load.
  4. Inspect EGR valve electrical connector and wiring for corrosion, chafing, or pin damage; perform pin drag and continuity checks to PCM.
  5. Command EGR valve through scan tool (if supported) and monitor actual position feedback; look for inability to close or erratic response.
  6. Inspect EGR cooler and cooler bypass valve for leaks, clogging, or bypass valve control circuit faults; P2457 relates to cooler bypass valve performance on this platform.
  7. Review recent regen history and EGT sensor data; excessive soot loading can contribute to EGR valve sticking.
  8. Clear codes, road test under conditions that set the monitor, and re-evaluate for repeat P042E.

Common mistake to avoid

Replacing the EGR valve without testing it. If the valve still moves freely, a carbon cleaning often fixes the flow code; and if it opens on command but the code stays, the blockage is in the passages or cooler, not the valve. Source: FleetRabbit — EGR valve problems and repair.

Parts and tools you may need

Tools you’ll need

Rough cost and difficulty

Likely repairPartsShop laborWho usually does it
EGR valve/passage carbon cleaning$20–$1001–4 hrsDIY with tools and a manual
Wiring or connector repair$10–$1001–4 hrsDIY with tools and a manual
EGR position/temperature/differential pressure sensor$60–$3000.5–1.5 hrsDIY with tools and a manual
EGR cooler$400–$1,0008–15 hrsShop

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If diagnosis points to internal EGR valve failure, cooler leak, or requires removal of high-temperature exhaust components, have a qualified diesel technician perform inspection and repair. Do not attempt step-by-step repair of safety-critical systems. If the vehicle enters limp mode or shows signs of coolant loss/white smoke, stop driving and seek professional service.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources

  1. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎ ↩︎ ↩︎

  3. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎

  4. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎

  5. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎