Diesel Trouble Codes

P2457 — Exhaust Gas Recirculation Cooling System Performance — 6.4 Power Stroke

P2457 on the 2008-2010 6.4L Power Stroke indicates the PCM has detected the EGR cooler is not cooling recirculated exhaust gas as expected. On this platform…

Updated October 15, 2026

What it means

The PCM has determined that the EGR cooler is not cooling the recirculated exhaust gas as much as expected. On the 6.4L the EGR system uses coolant-cooled EGR coolers. P2457 commonly points to a fouled, restricted or leaking EGR cooler, low coolant flow through it, or an EGR temperature sensor fault.1

Most likely causes

  1. EGR cooler internal restriction or fouling reducing heat transfer — Carbon buildup or internal blockage limits coolant-to-exhaust heat exchange, so post-cooler EGR temperature stays higher than expected.1
  2. EGR cooler coolant flow restriction or low coolant flow — Restricted coolant passages, clogged cooler inlet/outlet, or system-wide coolant flow issues reduce cooling capacity.1
  3. EGR cooler internal leak allowing coolant into exhaust or exhaust into coolant — A leaking cooler can alter temperature readings and cooling performance, and is a known failure mode for the 6.4L EGR cooler.1
  4. EGR temperature sensor or related circuit fault giving incorrect temperature feedback — Erroneous temperature input can cause the PCM to infer poor cooler performance even if cooling is adequate.1

How to diagnose

  1. Verify freeze frame and monitor EGR temperature sensor data during a controlled drive to see if post-cooler temperatures remain high relative to expected values.
  2. Inspect coolant level, condition, and signs of coolant loss or contamination; check for white smoke or sweet odor indicating cooler leakage.
  3. Check EGR cooler coolant supply and return for flow restriction, debris, or blockage; verify coolant system pressure and circulation.
  4. Inspect EGR temperature sensor connector and wiring for heat damage, corrosion, or loose connection; compare sensor readings to a known-good reference or scan tool rationality.
  5. Review related EGR codes and data such as EGR flow/position codes to differentiate a true cooling performance issue from a sensor or control problem.

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
Coolant hose or leak repair$20–$2000.5–3 hrsDIY with tools and a manual
Exhaust gas temperature sensor$50–$2500.5–1.5 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 coolant loss, white smoke, or overheating is present, or if diagnostic data is inconclusive, have a qualified diesel technician inspect the EGR cooler and cooling system before operating the vehicle. High-pressure fuel and exhaust systems require trained personnel and proper safety procedures.

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) ↩︎ ↩︎ ↩︎ ↩︎ ↩︎