P0470 P0471 P0472 P0473 and P0474 Exhaust Back Pressure Sensor Error Code Explained

P0470 to P0474 Exhaust Back Pressure Sensor Error CodeP0470 P0471 P0472 P0473 and P0473 exhaust back pressure sensor error codes are a fault codes or Diagnostic Trouble Code (DTC) that indicates your car's electrical circuit is malfunctioning for exhaust pressure area. This could be due to either an electrical or mechanical issue. To alert you that this fault has occurred, the check engine light or an error message will be activated.

These fault codes are related to all car manufacturers such as Audi VW Ford GM Opel Vauxhall Renault Nissan Peugeot Fiat Chevrolet Mercedes-Benz Mini BMW Seat Skoda Porsche and many other.

Error codes with explanation:

  • P0470 Exhaust Pressure Sensor A Circuit
  • P0471 Exhaust Pressure Sensor A Circuit Range/Performance
  • P0472 Exhaust Pressure Sensor A Circuit Low
  • P0473 Exhaust Pressure Sensor A Circuit High
  • P0474 Exhaust Pressure Sensor A Circuit Intermittent

What causes it?

Both gas or diesel engines that use variable nozzle turbochargers can be affected by this fault. When the incoming signal sent by the exhaust pressure sensor does not work simultaneously with the intake manifold pressure or ambient air pressure, a P0472 code will be activated. The P0472 error code can be caused by a fault with the exhaust back pressure sensor, the exhaust back pressure sensor harness or when there is an inadequate electrical connection in the exhaust back pressure sensor circuit. Other causes can include an obstruction in a clogged tube preventing the pressure sensor connecting to the exhaust manifold, air inlet or charge air leaks, and leaks in the exhaust gas recirculation system causing issues. It is also possible, although highly unlikely, that the power-train control module, the vehicle's control unit, has failed.

How to fix it

Prior to taking your vehicle to a mechanic, you can try some basic tests.

To test if the fault is with the power supply circuit not being powered up, disconnect the harness that runs to the exhaust pressure sensor.

To check if the tube connecting the exhaust manifold to the exhaust pressure sensor is blocked, try to run air through it; if the air does not go through easily, check for a blockage with a narrow wire. It may be possible to carefully dislodge the obstruction and after checking the air can run through again, you can reconnect the tube, to see if the P0472 exhaust back pressure sensor error code is still activated.

To check the exhaust pressure sensors, thoroughly inspect all wiring to check if there is any damage and replace or repair any wiring or connectors that are shorted or corroded. Dirty terminals can be effectively cleaned using an electrical contact cleaner with a small plastic bristle brush. Once dry, apply some dielectric silicone compound to where the terminals come into contact, to ensure the tubes that connect to the turbocharger do not have any leaks. Finally, check all of the hose and band clamps to ensure all of the tube connections are secure around the turbocharger.

Once you have completed all of these checks, you could try to install a new sensor. To find the exhaust back pressure sensor, look at the engine at the rear left, the sensor is next to the left exhaust gas recirculation positioner. After changing the sensor and before you drive your vehicle, ensure you clear the codes. You will know if changing the sensor has worked if your engine power returns to a normal range.

If you have been unable to fix a P0470 P0471 P0472 P0473 or P0474 depending which one code is popping out on your OBD-II reader screen, it is important to take your vehicle to be checked by a qualified mechanic. The code indicates the engine is not working properly and if ignored, this could even cause your vehicle to stop working when you are driving it. To avoid a potential accident.