What are the common causes of P2457?

A plugged or internally leaking EGR cooler A. Low coolant flow through EGR cooler A. A failed EGR cooler A temperature sensor. Coked EGR passages reducing cooler effectiveness.

Read EGR cooler A inlet and outlet temperatures on a scan tool. Check coolant level and flow through the cooler. Inspect the EGR cooler A for plugging or leaks. Compare the temperature drop across the cooler to spec. Replace the EGR cooler A if efficiency stays low. Clear the code and retest.

P2457

EGR Cooler A Efficiency Below Threshold

System: Auxiliary emission controls (P code)
Lamp: Check Engine Light
Category: Powertrain - Auxiliary Emissions Controls

What it means

P2457 means EGR Cooler A Efficiency Below Threshold.

Check these first

A plugged or internally leaking EGR cooler A
Low coolant flow through EGR cooler A
A failed EGR cooler A temperature sensor
Coked EGR passages reducing cooler effectiveness

What to do next

Read EGR cooler A inlet and outlet temperatures on a scan tool
Check coolant level and flow through the cooler
Inspect the EGR cooler A for plugging or leaks
Compare the temperature drop across the cooler to spec
Replace the EGR cooler A if efficiency stays low
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.