P0473: High input exhaust pressure sensor

Introduction

The DTC P0473 trouble code indicates a problem with the exhaust system pressure sensor, specifically a high input. This trouble code is common in vehicles equipped with diesel engines and can cause a variety of engine performance and emissions issues. In this article, we will explore the symptoms, causes, diagnosis, and possible solutions for the P0473 code, providing auto mechanics with a step-by-step guide to addressing this problem.

Symptoms

When a P0473 error occurs, symptoms can vary from vehicle to vehicle. However, some of the most common signs include:

  • The check engine light (Malfunction Indicator Lamp - MIL) comes on.

  • Reduced engine performance, with possible loss of power.

  • Increased fuel consumption.

  • Excessive exhaust fumes or abnormalities in the color of the fumes.

  • Slow acceleration or poor accelerator pedal response.

Cause

The causes of the P0473 error can be different and often require an in-depth analysis. Here are some of the most common causes:

  • Exhaust pressure sensor failure :
    The sensor itself may be faulty, causing incorrect pressure readings.

  • Electrical problems :
    Damaged wires, oxidized connectors, or defects in the sensor power circuit can lead to a high input.

  • Engine control unit (ECU) malfunction :
    The engine control unit may misinterpret the data from the sensor.

  • Pipeline problems :
    Blockages or leaks in the exhaust system can affect the pressure and, consequently, the operation of the sensor.

  • Auxiliary systems :
    A malfunctioning exhaust gas recirculation (EGR) system can contribute to incorrect sensor readings.

Diagnosis

Diagnosing a P0473 error requires the use of appropriate scan tools. Here are the steps to follow:

  1. Vehicle Scan :
    Use a diagnostic tool to read stored DTC codes. Note any related codes, such as P0470 or P0471, which may indicate similar problems.

  2. Visual inspection :
    Visually inspect the exhaust pressure sensor and associated electrical wiring for signs of wear or damage.

  3. Sensor Test :
    Measure the resistance and output voltage of the exhaust pressure sensor to check if it falls within the specification values provided by the manufacturer.

  4. Circuit Check :
    Use a multimeter to check the continuity and resistance of the wiring between the sensor and the ECU.

  5. Pipeline check :
    Make sure there are no blockages or leaks in the exhaust system that could affect the operation of the sensor.

Resolution and repair

Once you have identified the cause of the P0473 error, you can proceed with the resolution. Here are some common solutions:

  • Sensor Replacement :
    If the exhaust pressure sensor is faulty, it must be replaced. Make sure to use a quality replacement to ensure proper operation.

  • Wiring Repair :
    If there are damaged wires or oxidized connectors, they must be repaired or replaced to ensure proper electrical connection.

  • Replacing the engine control unit :
    In rare cases, if the engine control unit is faulty, it may require replacement or reprogramming.

  • Cleaning or replacing drain pipes :
    If there are blockages in the drain system, it is essential to remove them or replace the damaged parts.

Insight: Components involved in the failure

For a deeper understanding, it is useful to analyze the mechanical and electrical components involved in the P0473 code:

  • Exhaust pressure sensor :
    This sensor measures the exhaust gas pressure and sends the data to the ECU. It is essential for the correct functioning of the engine management system and the EGR system.

  • Engine Control Unit (ECU) :
    This unit processes information from the sensors and regulates the operation of the engine. An error in its programming can lead to incorrect readings.

  • Exhaust system :
    This includes pipes, mufflers and in some cases the EGR system. Blockages or leaks can affect pressure readings, causing the engine to run poorly.

Conclusions

The P0473 error code is a warning sign for auto repair professionals. Its diagnosis and resolution require technical expertise and a thorough understanding of the mechatronic systems involved. With the right tools and methodologies, you can address this problem effectively, restoring vehicle performance and ensuring compliance with emissions regulations. If you need additional information or support, do not hesitate to contact industry experts or consult the specific technical documentation for your vehicle.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.