GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Express - AWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P2457

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2457: Exhaust Gas Recirculation (EGR) Cooling System Performance

Circuit/System Description

The exhaust gas recirculation (EGR) cooler must remain within a specific temperature range to efficiently reduce emissions. Engine coolant flowing through the EGR cooler helps cool the exhaust gases flowing to the EGR valve. The EGR cooler has internal coolant passages and metal fins between the passages to help carry away excessive exhaust gas heat. This diagnostic monitors the temperature of the EGR cooler by monitoring both EGR temperature sensors while the EGR valve is active. If the EGR cooler temperatures exceed a calibrated threshold, this diagnostic will run and fail.

Conditions for Running the DTC
    • DTCs P040C, P040D, P041C, P041D or P040F are not set.
    • The ignition is ON.
    • The engine is not in diesel particulate filter (DPF) regeneration.
    • The engine coolant is greater than 50°C (122°F).
    • The EGR is active for greater than 60 seconds.
    • The EGR command is greater than 4 percent.
    • This diagnostic runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the temperature difference between both EGR temperature sensors si not within a calibrated range, for greater than 3 seconds. The difference can be from 1°C to 10°C depending on operating conditions.

Action Taken When the DTC Sets

DTC P2457 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P2457 is a Type B DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Verify that DTCs P0116, P0117, P0118, P0128, P040C, P040D, P041C, P041D or P040F are not set.
    2. ⇒If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Engine running, observe the DTC information with a scan tool. DTC P2457 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Inspect the engine cooling system for the following:

    • Low engine coolant level or engine overheating condition
    • Damage, restrictions, or leaks
    • Contaminated engine coolant
    • Damage, restricted, or leaking EGR cooler pipes and hoses--Refer to Symptoms - Engine Cooling.
       ⇒If the engine cooling system, pipes and hoses are OK, replace the EGR cooler and gaskets.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Exhaust Gas Recirculation Valve Cooler Replacement
    •  Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement