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Error code P0472 is defined as Exhaust Pressure Sensor Low. This means there’s a problem with the vehicle’s electrical circuit, often due to issues with the back pressure sensor.
This code is a generic trouble code, meaning it applies to all vehicles equipped with variable nozzle turbochargers (both gasoline and diesel engines), which started around 2005 on Ford trucks equipped with 6.0L diesel engines, all Ford EcoBoost engines, and eventually to Cummins 6.7L in 2007; Mercedes lineup with 3.0L engines in 2007 and the Cummins 3.0L 6 cyl in Nissan pickups starting in 2015. This code also applies to some VW vehicles models.
Error code P0472 means there’s a problem with the vehicle’s electrical circuit, though the source of the problem can be either electrical or mechanical failure. This problem stems from exhaust back pressure sensor not working properly.
Error code P0472 relates to the incoming signal sent by the exhaust pressure sensor not coinciding with the ambient air pressure or intake manifold pressure. This situation can happen with the Error Code P0473 as well.
Other related error codes include:
- Error Code P0470 Exhaust Pressure Sensor “A” Circuit
- Error Code P0471 Exhaust Pressure Sensor “A” Circuit Range/Performance
- Error Code P0473 Exhaust Pressure Sensor “A” Circuit High
- Error Code P0474 Exhaust Pressure Sensor “A” Circuit Intermittent
As with other error codes, this code activates the Check Engine light and registers the code to the vehicle’s memory system. Other common symptoms include:
- Engine lacks power
- Manual regeneration will be impossible
- Eventually, the problem can lead to crank-no start as well
- A crank-no start (if a perform regeneration isn’t able to perform)
Different causes for this code include:
- Defective exhaust back pressure sensor
- Short or completely open exhaust back pressure sensor
- Poor electrical connection in exhaust back pressure sensor circuit
- Blocked tube that connects pressure sensor to the exhaust manifold
- Failed PCM (rare)
How to Check
Troubleshooting steps for this code may vary from the type of engine (gas or diesel), manufacturer, type of exhaust pressure sensor, and wire colors.
If possible, mechanics start their diagnosis by checking the PCM flash/reprogram protocol.
Next, they check the exhaust pressure sensor and all its connectors and wiring and look for signs of damages caused by rubbing, chaffing, bare wires, burn spots, and melted plastic.
Next, they take the connectors apart, and then look for signs of burnt or corroded terminals, and possibly clean them.
Next, they clear the vehicle’s memory off of diagnostic trouble codes using a scan tool to see if the codes come back. If they do, the sensor and various circuits must be tested.
Next, they will disconnect the harness that leads to the exhaust pressure sensor using the DVOM (digital volt/ohm meter) and then test the power supply circuit that runs to the sensor to make sure everything is powered up.
How to Fix
Common repairs for this code include:
- Cleaning and replacement of damaged in the wires of the EPS
- If the connectors were proven to be the problem, erasing the code from memory should clear the screen as opposed to the code returning
- If the code comes back, circuits and sensors must be tested
- EPS voltage must be checked to see if it has suffered from failure
Error Code P0472 is often misdiagnosed as a fault in the exhaust gas recirculation (EGR). Though the exhaust back pressure tube may be found close to the EGR valve, this code must be diagnosed completely.
Though this code doesn’t pose an extreme danger, it’s still very important to have it checked by a qualified technician as soon as possible, as it will keep the engine from performing to its full potential and can lead to more problems in the future. The worst case scenario is that this code can cause your vehicle to stop working while you’re driving, which can be very dangerous.