Code Definition

P2457 — Exhaust Gas Recirculation Cooling System Performance

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2457

P2457 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2457 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2457 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

P2457 is set when the engine control module determines the EGR cooler is not reducing the temperature of recirculated exhaust gas by the expected amount. The module compares measured EGR gas temperature against a modelled value derived from engine load, coolant temperature and commanded EGR flow, and if the cooler falls short of that model across a monitored period the code is stored. The most common physical cause is internal fouling, where soot and oil vapour build a layer on the cooler core that both insulates it and restricts flow. On the Isuzu D Max and MU X with the 4JJ1 engine, and on m...

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