Technical Description of OBD-II Trouble Code
The circuit for the Exhaust Pressure Sensor is experiencing intermittent or erratic behavior.
What does that mean?
This generic diagnostic trouble code applies to engines with variable nozzle turbochargers, such as Ford trucks with 6.0L diesel engines starting from 2005, Ford EcoBoost engines, Cummins 6.7L engines from 2007, Mercedes 3.0L engines from 2007, and Cummins 3.0L 6 cyl engines in Nissan pickups from 2015. However, this code may also occur in other vehicle makes.
This code indicates a discrepancy between the incoming signal from the exhaust pressure sensor and the intake manifold pressure or ambient air pressure during engine operation. The issue can be either an electrical circuit fault or a mechanical problem.
Codes P047B, P047C, or P047D may also be present alongside P047E. These codes differ in the duration of the problem and the specific electrical or mechanical issue with the sensor, circuit, or engine controller.
Troubleshooting steps may vary depending on the manufacturer, whether the engine is gas or diesel, and the type of exhaust pressure sensor and wire colors used. Consult a vehicle-specific repair guide to identify the “B” sensor for your particular vehicle.
A typical exhaust pressure sensor:
Related trouble codes for exhaust pressure sensor “B”:
Symptoms
Symptoms of a P047E engine code may include:
Potential Causes
The common causes for this code to appear are:
Diagnostic and Repair Procedures
Start by searching for any technical service bulletins (TSBs) related to your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to address this issue, so it’s worth checking before pursuing other avenues.
Next, locate the Exhaust Pressure Sensor in your vehicle. Once found, disconnect the tube connecting the sensor to the exhaust manifold. Attempt to blow through the tube or use a small piece of wire to dislodge any trapped carbon causing the fault code.
If the tube is clear, visually inspect the connectors and wiring for any signs of damage such as chafing, rubbing, bare wires, burn spots, or melted plastic. Separate the connectors and carefully examine the terminals inside for corrosion, burns, or unusual green discoloration. If necessary, clean the terminals using electrical contact cleaner or rubbing alcohol and a plastic bristle brush. After cleaning, let them air dry and apply dielectric silicone compound to the contact points.
Ensure that the tube connecting the turbocharger to the intake manifold is not leaking. Inspect all tube connections around the turbocharger and intake manifold, and tighten any loose hose or band clamps.
If you have a scan tool, clear the diagnostic trouble codes from memory and monitor if the code returns. If it doesn’t, the issue was likely with the connections.
If the code persists, further testing of the sensor and its circuits is necessary. Typically, the Exhaust Pressure Sensor has 3 wires. Disconnect the harness connected to the sensor and use a Digital Volt Ohm Meter (DVOM) to test the 5V power supply circuit (red lead to the 5V power supply circuit, black lead to a good ground). If there is 12 volts instead of 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts or consider a possible PCM failure.
If the power supply circuit is functioning correctly, use the DVOM to check for 5V on the Exhaust Pressure Sensor signal circuit (red lead to the sensor signal circuit, black lead to a good ground). If there is no 5 volts or if you measure 12 volts, repair the wiring from the PCM to the sensor or consider a possible PCM failure.
Next, verify that the Exhaust Pressure sensor has a good ground. Connect a test light to the positive terminal of a 12V battery and touch the other end to the ground circuit of the Exhaust Pressure Sensor. If the test light doesn’t illuminate, there is a problem with the circuit. If it does illuminate, wiggle the wiring harness connected to each terminal to check for intermittent connections.
If all previous tests pass and the P047E code persists, try wiggling the sensor wiring harness while monitoring the scan tool for code recurrence. If the code returns, it likely indicates an intermittent connection in the harness. If not, it suggests a faulty Exhaust Pressure Sensor, although a failed PCM cannot be ruled out until the sensor is replaced.
