P0403 Fault Code

Exhaust Gas Recirculation Circuit Malfunction

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0403 fault code indicates a malfunction within the Exhaust Gas Recirculation (EGR) circuit. This system plays a crucial role in reducing nitrogen oxide emissions by diverting a portion of the exhaust gases back into the engine's intake. When there's a fault in this circuit, it can lead to increased emissions and poor engine performance.

• The EGR system consists of valves, pipes, and sensors that work together to regulate the exhaust flow.
• A malfunctioning EGR can also trigger the check engine light on the dashboard.

What are the symptoms of the P0403 code?

Drivers may experience the following symptoms when the P0403 code is active:

• Check engine light illuminated on the dashboard.
• Decreased engine performance, such as reduced power or sluggish acceleration.
• Increased fuel consumption due to poor air-fuel mixture.
• Rough engine idle or stalling.
• Unusual engine noises related to exhaust or intake airflow.

What causes the P0403 code?

Common causes of the P0403 code include:

• A faulty EGR valve that is stuck open or closed.
• Wiring issues such as frayed wires or bad connections.
• A malfunctioning EGR position sensor that fails to provide accurate readings.
• Blockages in the EGR passageways due to carbon buildup.
• Software issues in the engine control module (ECM).

How to fix P0403?

To resolve the P0403 fault code, the following steps can be taken:

• Inspect and repair any damaged wiring or connectors in the EGR circuit.
• Replace a faulty EGR valve with a new one if it is found defective.
• Clean out any carbon buildup in the EGR passageways to ensure proper flow.
• Check and replace a malfunctioning EGR position sensor as needed.
• If software issues are suspected, reprogram or update the engine control module (ECM).