Fix P0471: Mechanic’s solutions that WORKED

The P0471: Exhaust Pressure Sensor Range/Performance code signals a problem with the exhaust pressure sensor’s range or performance, indicating that the sensor’s readings are outside of the expected range. This could be due to a variety of factors affecting the exhaust system or sensor itself.

P0471 quick overview

Meaning	P0471: Exhaust Pressure Sensor Range/Performance
Is it serious?	This code can be serious as it may indicate issues that affect the vehicle’s performance and emissions system.
Possible causes	– Faulty exhaust pressure sensor – Clogged or damaged exhaust system (e.g., DPF) – Leaks in the turbocharger system – Corrosion or damage to sensor connectors – Wiring issues between the sensor and ECU
How to diagnose?	Inspect Sensor and Connector: Look for corrosion or damage at the exhaust pressure sensor and its connector. Check Exhaust System: Examine the exhaust components for blockages or damage. Verify Wiring Harness: Check for any damage or issues in the wiring circuit. Perform Manual Pressure Test: Manually verify exhaust back pressure against ECU data. Evaluate Sensor Output: Check the sensor’s voltage output at varying engine conditions. Inspect Turbocharger System: Look for leaks or issues in the turbocharger components. Review ECU Updates: Check for any available software updates for the vehicle’s ECU.

How to fix P0471 – learn from mechanics

I looked into P0471 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Dodge

Vehicle Information: 2015 Ram 3500 SLT 6.7L

Issue + Repair History:

• Truck towed in with dead batteries; runs with no power, black smoke, stalls after battery change.
• Communication barrier with customer; unclear how long issue has been present.

Computer Codes & Descriptions:

• P2471 – Exhaust Temperature Sensor 1/4 Circuit High
• P0471 – Exhaust Pressure Sensor 1 Performance (Pending)
• U059E – Implausible Data Received NOx Sensor Module 1 (Pending)

Suggestions to Fix Issue:

• Communicate with customer using Google Translate to understand any prior events like jump starts or fuel contamination.
• Start diagnostics with NOx sensor data, exhaust pressure sensor psi reading, and EGT 1 temperature reading.
• Consider exhaust system issues, particularly clogging and sensor failures.
• Diagnose based on the codes, focusing first on P0471 to check exhaust back pressure.
• Suspect a plugged particulate filter; further testing recommended.

Final Fix:

• Replaced the catalytic converter and two exhaust temperature sensors.
• Performed a forced regeneration and road-tested the vehicle; resolved the issue.

Case #2: Ford

Vehicle Information: 2014 Ford F-350 Super Duty XLT 6.7L

Issue + Repair History:

• Came in with reduced power light, turbo overboost, and exhaust pressure codes.
• Checked exhaust and boost pressure, appeared in spec but power was intermittently reduced.
• Snap-on scan tool indicated skewed exhaust pressure sensor readings; replaced but issue persisted.
• Matco scanner readings for exhaust, MAP, and BARO were in spec.
• Replaced MAP sensor; P0234 and P0471 resolved, but P132B persisted at idle.
• No change in MAP value at idle when operating wastegate and VGT actuator.

Suggestions to Fix Issue:

• Clean the tube going to the EBP sensor.
• Set RPM to 1200, actuate VGT with EGRDC at 0% to check for changes in MAF, EBP, and MGP readings.
• Check for boost leaks, frozen VGT, or turbo failure.
• Inspect turbine and compressor for contact with housing, indicating a need for turbo replacement.
• Perform KOER test to hear if the turbo spools correctly.
• Consider aftercooler issues, particularly in higher mileage trucks.

Final Fix:

• Found excessive clearance on turbo shaft upon removal.
• Replaced turbo unit, cleared codes, and performed regeneration of particulate filter, resolving the issue.

Case #3: Mercedes

ehicle Information: 2013 Mercedes-Benz Sprinter 2500 3.0L Diesel

Issue + Repair History:

• MIL illuminated with code P0471.
• Customer reports intermittent power loss, especially under load.
• Previous attempts to clear the code were unsuccessful.

Suggestions to Fix Issue:

• Inspect the exhaust pressure sensor and its connector for corrosion or damage.
• Check the exhaust system for leaks or blockages that could affect sensor readings.
• Verify the wiring harness for shorts or opens in the circuit back to the ECU.

Final Fix:

• Found corrosion at the exhaust pressure sensor connector. After cleaning the connector and replacing the sensor due to damage from corrosion, the code was cleared, and the vehicle’s performance was restored.

Case #4: Ford

Vehicle Information: 2010 Ford F-250 Super Duty 6.4L Diesel

Issue + Repair History:

• P0471 code set, along with complaints of reduced engine performance and increased fuel consumption.
• Historical data shows sensor was replaced a year ago.

Suggestions to Fix Issue:

• Perform a manual pressure test to verify the exhaust back pressure against the ECU data.
• Check for clogged exhaust components, including the DPF, which could be causing inaccurate sensor readings.
• Evaluate the sensor’s voltage output at varying RPMs to ensure it changes appropriately.

Final Fix:

• The DPF was found to be partially clogged, affecting exhaust back pressure readings. Performed a forced regeneration of the DPF and reset the exhaust pressure sensor calibration. This resolved the P0471 code and improved vehicle performance.

Case #5: Audi

Vehicle Information: 2008 Audi A4 2.0T

Issue + Repair History:

• Engine light on with code P0471 present.
• Owner notes occasional rough idling and hesitation during acceleration.

Suggestions to Fix Issue:

• Inspect the turbocharger system for leaks that could impact the exhaust pressure sensor’s accuracy.
• Test the exhaust pressure sensor directly for proper operation.
• Review ECU software for updates that might address known issues with sensor range/performance.

Final Fix:

• A small leak was discovered in the turbocharger intercooler hose, affecting the exhaust pressure reading. Replacing the hose and resetting the ECU cleared the P0471 code. Performance issues were resolved following the repair.

Advice	Brief Description of Diagnostic Step
Inspect the exhaust pressure sensor and connector	Check for corrosion, damage, or loose connections at the sensor and its wiring.
Check the exhaust system for leaks or blockages	Examine the exhaust components, including the DPF, for any leaks or clogs that could affect pressure readings.
Verify wiring harness integrity	Look for shorts, opens, or damage in the wiring circuit between the sensor and the ECU.
Perform a manual pressure test	Manually test the exhaust back pressure against ECU data to verify sensor accuracy.
Test the sensor’s voltage output	Evaluate the sensor’s output at varying RPMs to ensure it changes appropriately with engine conditions.
Inspect the turbocharger system for leaks	Check turbocharger components, including intercooler hoses, for leaks that could impact sensor readings.
Review ECU software for updates	Check if there are any software updates available for the ECU that might correct sensor range/performance issues.