Fault code P047A – exhaust pressure sensor “B” malfunction

Fault code P047A is called “Exhaust Pressure Sensor “B” Malfunction” 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 P047A

This Diagnostic Trouble Code (DTC) is a general powertrain code. Error P047A is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

Fault code P047A – exhaust pressure sensor

Error code P047A OBD2 indicates that the incoming signal from the “B” exhaust pressure sensor does not correspond to the inlet manifold pressure. This may be an electrical or mechanical fault.

This code may also be present at the same time as P0471. The only difference between these two codes is how long the problem lasts. And also the type of electrical/mechanical problem that the sensor/circuit/engine controller is having.

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

Symptoms of vehicle malfunctions

The main signal that an error P047A 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 P047A is considered serious, as it may cause some problems with controllability and performance of the vehicle. The fault itself is easily solved by replacing the faulty exhaust pressure sensor.

Factors that can cause this error code

The error code P047A can mean that one or more of the following problems have occurred:

  • Blockage in the pipe from the pressure sensor to the exhaust manifold.
  • Faulty exhaust gas recirculation system (air leakage).
  • Exhaust pressure sensor failure
  • In rare cases, the transmission control module (PCM) may be defective.

How to fix or reset OBD-2 code P047A

Some suggested steps for troubleshooting and fix the error code P047A:

  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 P047A 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 “B” 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 P047A 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 P047A still comes up when you run all the tests, it probably indicates a faulty exhaust pressure sensor. But a failed PCM module also cannot be ruled out until the sensor is replaced.

On which vehicles does this problem occur most frequently

Fault code P047A can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Ford
  • Infiniti
  • Mercedes-Benz
  • Nissan (Juke, Qashqai)
  • Opel (Movano)
  • Renault (Duster, Master)
  • Toyota
  • Volkswagen (Jetta)
  • Volvo

Fault code P047A can sometimes be found with other errors. The most common are the following: P047B, P047C, P047D, P047E, P047F.


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