Code Definition

P2BAC — NOx Exceedence - Deactivation of EGR

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

About P2BAC

P2BAC 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.

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 P2BAC 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

This is an emissions reporting code found on diesel vehicles fitted with NOx sensors and an EGR system, and it is informational rather than a direct component fault. The ECM sets P2BAC when it has itself deactivated or heavily restricted exhaust gas recirculation because of another stored fault, and the resulting oxides of nitrogen in the exhaust have then exceeded the legislated threshold. In other words the module is recording the emissions consequence of a decision it made, so the code almost never stands alone. TaT members are seeing it most on Volkswagen Crafter, Amarok and Transporter, M...

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