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P0472 OBD-II Trouble Code: Exhaust Pressure Sensor Low

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P0472 code definition

A P0472 code means there is a problem with your vehicle’s electrical circuit, though the source could be electrical or mechanical. It stems from an exhaust back pressure sensor not working correctly.

What the P0472 code means

A P0472 code concerns the incoming signal sent by the exhaust pressure sensor because it’s not coinciding with the intake manifold pressure or ambient air pressure. The problem is strictly related to an issue with the electrical circuit. It often occurs with the P0473 code as well.

What causes the P0472 code?

There are a number of reasons you could be seeing the P0472 code displayed:

  • An exhaust back pressure sensor that is no longer working correctly
  • The exhaust back pressure sensor is suffering from a poor electrical connection
  • The exhaust back pressure sensor harness is shorted or open
  • There is an open in signal circuit occurring between the PCM and exhaust pressure sensor
  • There is an open between the PCM and the exhaust pressure sensor in the power supply
  • Short of power to ground in the signal circuit to the exhaust pressure sensor
  • A faulty exhaust pressure sensor internally shorted to the ground
  • The PCM has failed internally (this is the least likely reason)

What are the symptoms of the P0472 code?

  • Lack of power to the engine
  • Seeing the Check Engine Light come on
  • A manual regeneration is unable to perform
  • A crank-no start (if a perform regeneration isn’t able to perform)

How does a mechanic diagnose the P0472 code?

  • If possible, a PCM flash/reprogram protocol

  • Checking the exhaust pressure sensor, inspecting its connectors and wiring for rubbing, chafing, burn spots, bare wires, and melted plastic

  • Taking the connectors apart, inspecting for corroded or burnt terminals and possibly cleaning them

  • Clearing the diagnostic trouble codes from memory using a scan tool to see if the code returns. If it does, the sensor and various circuits will need to be tested.

  • Disconnecting the harness that leads to the exhaust pressure sensor with a DVOM (digital volt/ohm meter) and testing the power supply circuit that runs to the sensor to make sure it is powered up.

Common mistakes when diagnosing the P0472 code

The most common reason the P0472 code gets misdiagnosed is because it gets confused with an exhaust gas recirculation code. Even though the exhaust back pressure tube may be found close to the exhaust gas recirculation (EGR) valve, the P0472 code still needs to be diagnosed in a completely different way.

How serious is the P0472 code?

Although it’s not a code that represents extreme danger, it’s still a good idea to have a qualified mechanic take a look ASAP if you see P0472 displayed. Your engine simply isn’t performing as well as it could be which is only going to lead to more problems in the future. Worst case scenario, though, your vehicle may stop working completely even while you’re driving on the road, which could obviously be pretty scary (or at least very inconvenient).

What repairs can fix the P0472 code?

  • Replacing any damaged wires in the EPS and/or cleaning them
  • If the connectors were the problem, then erasing the code from memory should result in a clear screen as opposed to the code returning
  • If the code returns, testing the sensor and its circuits
  • Checking the voltage of the EPS to see if it has suffered from a failure

Additional comments for consideration regarding the P0472 code

Associated codes like P0471 and especially P0473 may occur along with P0472. They all relate to the same core issue, though, so addressing P0472 should clear out the others too.

Need help with a P0472 code?

The moment you see a P0472 code, contact YourMechanic and schedule an appointment with one of our certified mobile mechanics. You can sign up through our website or by calling us at 1-800-701-6230. The mechanic will then travel to either your home or place of business whenever is most convenient. We’d be happy to supply you with a quote first as well.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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