P0472 — Exhaust Pressure Sensor Low

Causes

• Failed/exhaust pressure sensor (internal fault)
• Open circuit or short to ground in sensor signal wire
• Poor or corroded connector/terminal
• Blocked, crushed or disconnected sensor port or hose
• Exhaust leak upstream of the sensor (affecting pressure reading)
• PCM/ECU fault or incorrect calibration

Symptoms

• Malfunction Indicator Lamp (MIL) illuminated
• Failed or inhibited diesel particulate filter (DPF) regeneration
• Reduced engine power or limp mode on some models
• Warning messages about DPF/EGR/Exhaust pressure on dashboard
• Poor fuel economy or unusual exhaust behavior

What to check

• Read stored/active codes and freeze-frame data with a capable scan tool; note conditions when code set
• Visually inspect sensor, connector and harness for damage, corrosion, oil or soot contamination
• Back-probe sensor connector and check for reference supply (usually 5V), ground continuity and signal voltage with ignition on
• Check for open or short to ground between sensor signal and PCM
• Use a hand vacuum/pressure pump (or calibrated pressure source) on the sensor port while monitoring live data to confirm sensor response
• Inspect and clear any blockages in the sensor port or reference hose; check exhaust for leaks upstream

Signal parameters

• Supply/reference: typically ~5 V reference from PCM (verify model-specific spec)
• Signal output: analog voltage 0–5 V (common range); low-pressure readings typically low voltage (example idle/no pressure ~0.3–1.5 V; high differential pressure higher voltage)
• Ground: solid chassis/ECM ground; low resistance to battery negative expected
• Response: output should change smoothly with applied differential pressure — no abrupt drops to 0 V

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