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Error Code P0470 is defined as Exhaust Pressure Sensor Malfunction. This means the sensor in charge of evaluating the exhaust pressure is not working due to a poor electrical connection or back pressure sensor.
This trouble code is a generic error code, which means it applies to all vehicles with variable nozzle turbochargers (diesel or gas), or vehicles made since 2006 on Ford trucks equipped with 6L diesel engines, Ford EcoBoost engines and the Cummins 6.7L in 2007, the 3.0L in the Mercedes lineup in 2007 and here recently the Cummins 3.0L 6 cyl in the Nissan pickups starting in 2015. That’s not to say you wouldn’t necessarily get this code in a VW or other make though.
Error Code P0470 happens when the sensor in charge of determining the exhaust pressure is not working properly. This code happens when the incoming signal from the exhaust pressure sensor not matching the pressure from the intake manifold or ambient pressure at key on. This can be caused by a fault in the electrical circuit or a mechanical failure.
Error Code P0470 is related for Error Code P0471. The only difference between the two is the duration the code persisted for the electrical/mechanical problem the vehicle is experiencing.
As with other trouble codes, P0470 triggers the Check Engine light. Other symptoms include:
- Lack of power from the engine
- Unable to perform manual regeneration
- This problem can lead to crank-no-start condition
There are many factors that can lead to this error code, some of the typical causes are:
- Faulty exhaust back pressure sensor
- Shorted or open exhaust back pressure sensor
- Poor electrical connection with exhaust back pressure sensor circuit
- Blocked or clogged tube that runs from pressure sensor to the exhaust manifold
- Leaks in the exhaust gas recirculation system, air inlet or charge air leaks
- Failed PCM (rare, but possible)
How to Check
Mechanics start their diagnosis for vehicles with this error code by checking the exhaust back pressure sensor. They disconnect the tube that connects the exhaust manifold to the exhaust pressure sensor and try to run air through it. If that step proves to be impossible, they will dislodge whatever is causing the blockage using a wire.
Next, mechanics will check the wiring involved, and look for signs of damage. The connectors will also be checked thoroughly.
To test the power supply circuit and make sure it’s working properly, the harness that runs to the exhaust pressure sensor can also be disconnected.
If nothing seems to work, then the problem is most likely caused by a malfunctioning exhaust pressure sensor.
How to Fix
Repairs for this error code are pretty simple, and as we have covered above, the most basic repair to get rid of the error code is to replace the back pressure sensor. Other common fixes are:
- If not, the sensor, along with other associated circuits, must be tested to make sure the former is not malfunctioning due to the latter
- To confirm that the power supply for the sensor is working properly, it must be tested as well
- Power supply to exhaust pressure sensor must be gauged as well
Error Code P0470 keeps the vehicle from reaching its potential in power and performance. In many cases, this problem can be solved by simply replacing the malfunctioning sensor. However, you need to make sure everything is working fine before replacing the sensor.
When diagnosing, start by checking the back pressure sensor and check everything before moving on to the next step of diagnosis to make sure you don’t waste time and money on misdiagnosis and unnecessary replacements.