What Does P0471 Mean?
The exhaust pressure sensor A is not reading within the expected range or its output does not correspond to actual exhaust pressure conditions. This sensor is critical on diesel and turbocharged engines for monitoring exhaust backpressure to control the turbocharger, EGR system, and diesel particulate filter (DPF) regeneration. Incorrect readings can cause poor turbo boost control, reduced power, and failed DPF regeneration attempts.
Common Causes
30%
Clogged exhaust pressure sensor A tube or port with soot
25%
Failed exhaust pressure sensor A
20%
Cracked or disconnected pressure line from exhaust to sensor
15%
Exhaust leak upstream of the sensor affecting pressure readings
10%
Wiring issue in the exhaust pressure sensor A circuit
Diagnostic Steps
1
Compare the exhaust pressure sensor A PID to the expected value at idle (typically 0.5-2.0 psi above atmospheric). At higher RPM under load, the reading should increase proportionally. Compare to a known good pressure gauge if available.
2
Inspect the pressure line from the exhaust pipe to the sensor for cracks, disconnections, soot blockage, or melting. Blow compressed air through the line to verify it is clear.
3
Remove the exhaust pressure sensor and clean the sensing port. Apply a known pressure using a hand pump and verify the sensor output matches the manufacturer's pressure-vs-voltage specification.
4
Check for exhaust leaks between the turbo outlet and the sensor tap point. Spray soapy water on connections while the engine is running at 2,000 RPM and watch for bubbles.
5
Measure the reference voltage (typically 5V) and ground at the sensor connector. Verify signal voltage changes when pressure is applied to the sensor port using a hand pump.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The exhaust pressure sensor A is not reading within the expected range or its output does not correspond to actual exhaust pressure conditions. This sensor is critical on diesel and turbocharged engines for monitoring exhaust backpressure to control the turbocharger, EGR system, and diesel particula...
The most common cause of P0471 (Exhaust Pressure Sensor "A" Circuit Range/Performance) is: Clogged exhaust pressure sensor A tube or port with soot
Typical repair costs for P0471 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle may enter a reduced power mode (limp mode). Driving is possible but with limited performance. On diesel vehicles, failed DPF regeneration can lead to a plugged DPF requiring expensive replacement. Have this diagnosed promptly, especially on diesel-equipped vehicles.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0471 to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Turbo / DPF System
Difficulty
Type
Generic (SAE)
Recommended Tools
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