P047C Exhaust Pressure Sensor B Low Input
OBD-II Trouble Code Technical Description
Exhaust Pressure Sensor "B" Low Input
What does that mean?
This generic powertrain/engine diagnostic trouble code applies to all engines that use variable nozzle turbochargers (gas or diesel), starting around 2005 on Ford trucks equipped with 6.0L diesel engines, all Ford EcoBoost engines, and eventually leading to 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.
This code is strictly concerned about the incoming signal from the exhaust pressure sensor not matching intake manifold pressure or ambient air pressure at key on. This is strictly an electrical circuit fault.
Code P047B may also be present at the same time as the P047C. The main difference between these two codes is P047C is only electrical while P0471 can be the result of a mechanical or electrical fault. It is typically recommended to start with the P047C (electrical) first before moving on to the P047B (electrical/mechanical) next. This way, if the problem is electrical, there is a higher probability of repair by starting with the electrical.
Troubleshooting steps may vary depending upon manufacturer, gas or diesel, type of exhaust pressure sensor and wire colors. Refer to a vehicle specific repair guide to determine which is the "B" sensor for your particular vehicle.
A typical exhaust pressure sensor:
Related exhaust pressure sensor "B" trouble codes:
P047A Exhaust Pressure Sensor "B" Circuit P047B Exhaust Pressure Sensor "B" Circuit Range/Performance P047D Exhaust Pressure Sensor "B" Circuit High P047E Exhaust Pressure Sensor "B" Circuit IntermittentSymptoms
Symptoms of a P047C engine code may include:
Check Engine Light illuminated Lack of power Unable to perform manual regeneration – burn off the soot out of the particulate filter. Looks like a catalytic converter but has temp sensors and pressure sensor probes inserted into it. If unable to perform regeneration, eventually may become a crank-no start.Potential Causes
Typically the causes for this code to set are:
Open in the signal circuit between the exhaust pressure sensor and the PCM Open in the power supply circuit between the exhaust pressure sensor and the PCM Short to ground in the signal circuit to the exhaust pressure sensor Exhaust Pressure Sensor faulty – internally shorted to ground Possibly a powertrain control module (PCM) has failed (highly unlikely)Diagnostic and Repair Procedures
A good starting point is always a technical service bulletin (TSB) search for your particular vehicle. The vehicle manufacturer may have a PCM flash/reprogram to cover this issue, and it pays to check on this before you find you’ve gone down a long/wrong path.
Next, the locate Exhaust Pressure Sensor on your particular vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burn spots or melted plastic. Pull the connectors apart and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt or possibly green in color versus the normal metal color you are probably used to seeing. You can get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. If this is not possible, find some 91% rubbing alcohol and a light plastic bristle brush to clean them with. Afterwards let them air dry, get some dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and put some where the terminals come into contact.
If you have a scan tool, clear the
Read: 44
