Code Definition

P229E (13) — NOx Sensor Circuit Range/Performance (Bank 1 Sensor 2)

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

About P229E

P229E 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 P229E 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; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

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 P229E 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

DTC P229E indicates a range or performance fault from the NOx sensor on Bank 1 Sensor 2, the downstream sensor after the SCR catalyst. The module uses this sensor to measure how much oxides of nitrogen remain after treatment and to judge SCR efficiency and dosing. The code sets when the downstream NOx signal is present but implausible, for example failing to respond to changing exhaust conditions, disagreeing with the upstream sensor, or sitting outside the expected window over a calibrated period. Because this sensor verifies emissions performance, the fault commonly disables SCR efficiency m...

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