P0471 Exhaust Gas Pressure Sensor Out of Range / Performance

OBD-II Trouble Code -P0471 - Data Sheet

Exhaust Gas Pressure Sensor Out of Range / Performance

What does trouble code P0471 mean?

This Generic Powertrain / Engine DTC applies to all engines using variable nozzle turbochargers (gas or diesel) since about 2005 on Ford trucks equipped with 6.0L diesel engines, all Ford EcoBoost engines, and ultimately eventually leads to the Cummins 6.7 L model. 2007, 3.0L in Mercedes lineup in 2007 and recently here Cummins 3.0L 6-cylinder in Nissan pickups starting in 2015. This does not mean that you will not necessarily get this code on a VW or other model.

This code strictly refers to the fact that the input signal from the exhaust pressure sensor does not match the intake manifold pressure or ambient air pressure when the key is turned on. It could be an electrical fault or a mechanical fault.

P0470 can also be present at the same time as P0470. The only difference between the two codes is how long the problem lasts and the type of electrical / mechanical problem that the sensor / circuit / motor controller is experiencing. Troubleshooting steps may vary depending on the manufacturer, gasoline or diesel, type of exhaust pressure sensor and wire colors.

Typical Exhaust Pressure Gauge:

Related Exhaust Pressure Sensor Fault Codes:

• P0470 Exhaust Gas Pressure Sensor A Circuit
• P0472 Low sensor "A" exhaust pressure
• P0473 High Exhaust Gas Pressure Sensor "A"
• P0474 Exhaust Gas Pressure Sensor A Circuit Malfunction

Symptoms

Symptoms of a P0471 engine code may include:

• Check Engine light is on
• Lack of power
• Unable to perform manual regeneration - burn the particulate filter from the particulate filter. Looks like a catalytic converter, but it has temperature sensors and pressure sensors inserted into it.
• If regeneration fails, a non-cranking start may eventually occur.

Possible Causes of Code P0471

Usually the reason for installing this code is:

• Clogged tube from exhaust manifold to pressure sensor
• Exhaust Gas Recirculation / Air Intake / Charge Air Leaks
• Exhaust gas pressure sensor
• Powertrain Control Module (PCM) may have failed (unlikely)

Diagnostic and repair procedures

A good starting point is always to find a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a flash memory / PCM reprogramming to fix this problem and it's worth checking it out before you find yourself on the long / wrong path.

Then find the exhaust pressure sensor on your specific vehicle. Once detected, disconnect the tubing that connects the sensor to the exhaust manifold. Try to break through this. If that doesn't work, try running a small piece of wire through it to remove the carbon that's stuck inside, causing the DTC you're encountering. If you notice that quite a lot of water is escaping from it, this may be the reason for the code.

If the tubing is clean and loose, visually inspect the connectors and wiring. Look for scuffs, scuffs, exposed wires, burn marks, or molten plastic. Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look rusty, burnt, or possibly green compared to the usual metallic color you're probably used to seeing. If terminal cleaning is required, you can purchase electrical contact cleaner at any parts store. If this is not possible, find 91% rubbing alcohol and a light plastic bristle brush to clean them. Then let them air dry, take a dielectric silicone compound (the same material they use for bulb holders and spark plug wires) and place where the terminals make contact. Then check that the pipe connecting the turbocharger to the intake manifold is not leaking. Inspect all pipe connections around the turbocharger and intake manifold. Tighten all hose / tape clamps.

If you have a scan tool, clear the diagnostic trouble codes from memory and see if the code returns. If this is not the case, then there is most likely a connection problem.

If the code returns, we will need to test the sensor and associated circuits. There are usually 3 wires on the exhaust pressure sensor.

Disconnect the harness from the exhaust pressure sensor. Use a digital volt ohmmeter (DVOM) to check the 5V power supply circuit going to the sensor to make sure it is on (red wire to 5V power supply circuit, black wire to good ground). If the sensor is 12 volts when it should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts or possibly a faulty PCM.

If this is normal, with the DVOM, make sure you have 5V on the exhaust pressure sensor signal circuit (red wire to sensor signal circuit, black wire to good ground). If there is no 5 volts on the sensor, or if you see 12 volts on the sensor, repair the wiring from the PCM to the sensor, or again, possibly a faulty PCM.

If normal, check that the exhaust pressure sensor is properly grounded. Connect a test lamp to the 12 V battery positive (red terminal) and touch the other end of the test lamp to the ground circuit that leads to the exhaust gas pressure sensor circuit ground. If the test lamp does not light up, it indicates a faulty circuit. If it does light up, wiggle the wire harness going to each sensor to see if the test lamp blinks, indicating an intermittent connection.

If all tests have passed so far and you keep getting the P0471 code, it most likely indicates a faulty exhaust gas pressure sensor, although the failed PCM cannot be ruled out until the sensor is replaced.

COMMON ERRORS WHEN DIAGNOSING CODE P0471

One of the most common mistakes when diagnosing a code P0471 is that it thinks it is an EGR code. It is important for the mechanic to diagnose the correct code and perform the proper repair. After testing and repairing various parts of the system, it is also recommended to reset the codes and retest the vehicle.

HOW SERIOUS CODE P0471 IS?

When the code P0471 appears, you will probably still be able to drive your vehicle. However, this does not mean that you should ignore the problem. You may notice that the Check Engine light comes on and the car does not operate as it used to. You should not continue to drive in this condition as it may cause more problems in the long run. Instead, be sure to take your vehicle to a mechanic for proper repairs and diagnostics.

WHAT REPAIRS CAN FIX CODE P0471?

The following are some of the repairs a mechanic can perform to resolve a P0471 code.

• Use an OBD-II scanner to diagnose the car and see if the codes come back.
• Check wiring and connectors to make sure nothing is shorted or corroded. They will replace and repair as needed.
• Check exhaust pressure sensor.
• Check the hose connecting the exhaust pressure sensor to the exhaust manifold and make sure it is clean.

ADDITIONAL COMMENTS TO BE AWARE OF CODE P0471

If your vehicle has code P0471, you can probably still drive it. However, you don't want to drive for too long without checking it out. Even if you do not notice performance problems now, this does not mean that there are no problems. It is true that some of the older, high mileage vehicles may trigger false codes from time to time, but you cannot rely on this to apply to your vehicle. You should take the time to have it thoroughly checked by a mechanic who can diagnose and make appropriate repairs.

P0471 turbo pressure sensor fault (fix)

Need more help with your p0471 code?

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