Fault code P0471 – a step-by-step guide to diagnosing and fixing it

Error code P0471 is displayed and the check engine light is on - what does this mean?

DTC P0471 is recognized by the OBD system when a problem is detected with the exhaust gas temperature sensor upstream of the catalytic converter. This fault code indicates that the sensor is operating outside the expected voltage range or is delivering an implausible signal. For various manufacturers, this trouble code may also be referred to as "Exhaust Gas Temperature Sensor Circuit Range/Performance".

What causes can this error code have?

• Defective exhaust gas temperature sensor upstream of the catalytic converter
• Damaged or corroded cable connections to the sensor
• Short circuit or interruption in the sensor wiring
• Loose or dirty plug connections
• Defective engine control unit (ECU)
• Mechanical damage to the sensor fastening thread
• Contamination of the sensor due to soot or deposits

What symptoms occur in parallel with fault code P0471?

• Check engine light: The check engine light is permanently illuminated
• Increased fuel consumption: The vehicle consumes more fuel than usual
• Reduced engine power: Noticeable loss of power during acceleration
• Uneven idling: The engine runs unevenly at idle
• Exhaust problems: Increased emission values during the emissions test
• Regeneration problems: DPF regeneration problems can occur in diesel vehicles

How can I fix the problem with fault code P0471?

• Repairing fault code P0471 requires a systematic approach to identify the exact cause.
• Replace the sensor: Replace the defective exhaust gas temperature sensor completely, treating the thread with assembly paste and tightening the new component to the correct torque
• Carry out cable repair: Locate damaged cables to the sensor, cut out defective areas and repair with automotive-grade cables and soldered connections, then insulate
• Clean and secure plug connections: Clean all contacts on the sensor cable with contact cleaner, check for corrosion and connect firmly, replacing seals in the process
• Check and replace engine control unit: Test the ECU with professional diagnostic technology, replace the control unit if defective and have it reprogrammed
• Carry out sensor cleaning: If the sensor is dirty, remove it, remove soot and deposits with a special cleaner and reinstall it correctly