P1402 - FAULT CODE - OBD2

P1402 INFINITI, NISSAN: EGR FUNCTION OPEN

The EGR (Exhaust Gas Recirculation) system limits the amount of nitrogen oxide emissions produced. To achieve this goal, it is sent to the engine’s top inlet, causing it to mix with the resulting air/fuel charge. The fuel mixture can burn cooler through this process, so it reduces fuel chamber temperatures to reduce nitrogen oxide emissions.

The EGR system controls the flow rate of gases from the exhaust manifold to the intake manifold. The opening of the bypass passage of the system is adjusted on a volume control valve. A stepper motor moves the valve in steps corresponding to the output pulses of the ECM (Engine Control Module). The opening varies to achieve the optimum engine control, which is stored in the ECM memory under certain engine conditions.

The P1402 OBDII fault code is a manufacturer-specific code. In the case of Nissan and Infiniti brands, it indicates that the EGR Temperature Sensor has detected that the exhaust gas recirculation flow is not required by current conditions, and is interpreted as a high flow fault.

• Check Engine lamp ON.

Storage of the P1402 OBD2 diagnostic code occurs for one or more of the following reasons:

• The EGR volume control valve circuit wiring may be damaged.
• The EGR volume control valve may be leaking or blocked.
• Possibly the EGR temperature sensor is faulty.

To troubleshoot DTC P1402 OBDII, try this:

• Consult the TSB (Technical Service Bulletins).
• Check the EGR volume control valve harness for deficiencies caused by wear or corrosion. Fix if necessary.
• Check the volume control valve of the Exhaust Gas Recirculation System and check it for leaks or binding. Repair if necessary, and make appropriate corrections.
• Check the condition of the EGR temperature sensor. Measure its resistance and compare that value to the manufacturer's specifications. Replace it if you determine that it is in poor condition.