P0471: Exhaust Pressure Sensor Range/Performance

What Does P0471 Mean?

Code P0471 means the exhaust pressure sensor is providing readings that fall outside the expected range or do not change appropriately with engine operating conditions. The sensor may be reading, but the values do not correlate with RPM, load, or other parameters. This is often caused by a partially clogged pressure line or a drifting sensor.

Common Causes

• Partially clogged exhaust pressure sensor line
• Drifting or aging exhaust pressure sensor
• Soot buildup in the sensor port
• Cracked pressure hose leaking exhaust gases
• Restricted exhaust system affecting readings

Symptoms

• Check engine light on
• Reduced engine power or limp mode
• Incomplete DPF regeneration cycles
• Poor fuel economy
• Excessive black exhaust smoke on diesel engines

Diagnostic Steps

1. 1Compare exhaust pressure sensor readings to expected values at various RPMs
2. 2Remove and inspect the pressure line for soot or carbon blockage
3. 3Clean the sensor port and pressure line with compressed air
4. 4Test the sensor against a known accurate pressure gauge
5. 5Check for exhaust system restrictions such as a clogged DPF
6. 6Replace the sensor if readings remain out of range after cleaning

Estimated Repair Cost

Frequently Asked Questions