P2457

DTC P2457

Diagnostic Instructions

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

DTC Descriptor
DTC P2457
- Exhaust Gas Recirculation (EGR) Cooler Low Efficiency

Circuit/System Description

The Exhaust Gas Recirculation (EGR) cooler has internal coolant passages and metal fins between the passages to help carry away excessive exhaust gas heat. Engine coolant flowing through the EGR cooler helps cool the exhaust gases flowing to the EGR valve. The EGR cooler must remain within a specific temperature range to efficiently reduce emissions. The Engine Control Module (ECM) determines the efficiency of the EGR cooler by monitoring both EGR temperature sensors while the EGR valve is active. If the difference between the EGR cooler temperature sensors exceeds a calibrated threshold, this diagnostic will fail and the DTC will set.

Conditions for Running the DTC

* Engine speed is between 1,000-2,200 RPM.
* The engine is not in Diesel Particulate Filter (DPF) regeneration.
* The calculated fuel rate is greater than 20 mm(3).
* The engine coolant temperature is less than 123°C (253°F).
* The difference between the upstream EGR cooler temperature and the Engine Coolant Temperature (ECT) is greater than 40°C (72°F).
* The ambient air temperature is greater than -7°C (19°F).
* The EGR valve position is greater than 10 %.
* The Barometric Pressure (BARO) is greater than 74.8 kPa (10.9 psi).
* DTC P2457 runs once per driving cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the temperature difference between the EGR temperature sensors is not within a calibrated range, for greater than 30 s.

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 ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information. Verify that DTC P0116, P0117, P0118, P0128, P040C, P040D, P041C, P041D or P040F is not set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.

2. Engine running, observe the DTC information with a scan tool. DTC P2457 should not be 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
* Damage, restrictions, or leaks
* Contaminated engine coolant
* Damage, restricted or leaking EGR cooler and cooler pipes/hoses-Refer to Symptoms - Engine Cooling (Symptoms - Engine Cooling).

• If a condition is found repair or replace the affected component as necessary.
• If all inspections are normal, replace the EGR cooler and gaskets.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Exhaust Gas Recirculation Valve Cooler Replacement (Exhaust Gas Recirculation Valve Cooler Replacement)
* Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement (Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement)