Fault code P0473 – exhaust pressure sensor “A” high input

Fault code P0473 is called “Exhaust Pressure Sensor “A” High Input” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P0473

This Diagnostic Trouble Code (DTC) is a generic powertrain code. Error P0473 is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly from model to model.

Fault code P0473 – exhaust pressure sensor

Error code P0473 OBD2 indicates that the incoming signal from the “A” exhaust pressure sensor does not match the inlet manifold pressure. This may be an electrical circuit fault.

This fault may be present at the same time as P0471. The main difference is that P0473 is an electrical problem. And P0471 can be the result of a mechanical or electrical problem.

It is usually recommended to start with fixing P0473 (electrical) first, and then move on to P0471 (electrical/mechanical). This way, if the problem is electrical related, the likelihood of repair is increased.

The troubleshooting steps can vary depending on the manufacturer, gasoline or diesel. As well as the type of the exhaust pressure sensor and the colors of the wires.

Symptoms of vehicle malfunctions

The main signal that an error P0473 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Check engine control lamp on the control panel will light up (the code will be recorded in the ECM memory as a fault).
  2. Engine power drop.
  3. Exhaust pressure regulator may malfunction.

Fault P0473 is not considered serious, but if the problem is not solved for a long time, it can lead to more serious malfunctions. Therefore, if this code is detected, it is recommended that the problem be corrected as soon as possible.

Factors that can cause this error code

The error code P0473 can mean that one or more of the following problems have occurred:

  • Open circuit in signal line between exhaust pressure sensor and PCM.
  • Damage to the power supply circuit between the exhaust pressure sensor and PCM.
  • Short to earth in the signal circuit of the exhaust pressure sensor.
  • Faulty exhaust pressure sensor (internal short to ground).
  • In rare cases, powertrain control module (PCM) may malfunction.

How to fix or reset OBD-2 code P0473

Some suggested steps for troubleshooting and fix the error code P0473:

  1. First, connect an OBD-II scanner to the vehicle’s onboard computer and read all stored data and error codes.
  2. Then clear the error codes from the PCM memory and test-drive the vehicle to see if error P0473 appears again.
  3. If the error code appears again, confirm that there is a problem and continue diagnostics.

Diagnose and repair of problems

Locate the “A” exhaust pressure sensor on your vehicle. Disconnect the tube that connects the sensor to the exhaust manifold. If this is not possible, slip a small piece of wire through to remove any soot stuck inside.

If the tube is clean, inspect the connectors and wiring. Look for scuffs, exposed wires, burn spots, or melted plastic. Disconnect the connectors and carefully inspect the terminals inside the connectors.

Next, make sure the tubing that connects the turbocharger to the intake manifold is tight. Visually check all tubing connections around the turbocharger and intake manifold. Tighten all hose clamps.

If you have an error scanner, clear the diagnostic trouble codes from memory and see if code P0473 returns. If it doesn’t, it’s probably a connection problem.

If the code returns, you will need to test the sensor and associated circuits. Usually the exhaust pressure sensor has 3 wires. Use a digital multimeter to check the 5V power supply circuit going to the sensor.

If all is normal, check that the exhaust pressure sensor is securely grounded. Connect the test light, if it does not light up, this indicates a faulty circuit. If it lights up, jiggle the wiring harness going to the sensor to see if the check lamp flashes, indicating an intermittent connection.

If code P0473 still pops up when you run all the tests, it probably indicates a faulty exhaust pressure sensor. But a failed PCM module cannot be ruled out either until the sensor is replaced.

On which vehicles does this problem occur most frequently

Fault code P0473 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi (Q7)
  • Hyundai
  • Kia (Sorento)
  • Mercedes-Benz
  • Volkswagen (Passat)

Fault code P0473 can sometimes be found with other errors. The most common are the following: P0047, P0101, P0105, P0108, P0113, P0130, P0172, P0231, P0237, P0238, P0470, P0475, P0603.

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