What Does P047B Mean?
The exhaust pressure sensor 'B' signal is not tracking within the expected range for current operating conditions, or the sensor response is sluggish and fails performance checks. The ECM compares expected exhaust pressure against actual readings and has found a mismatch. The driver may notice poor turbo response, failed regeneration events, or reduced fuel economy.
Common Causes
30%
Partially blocked pressure sensing hose/tube causing delayed or incorrect pressure readings
28%
Exhaust pressure sensor 'B' degraded or drifted out of calibration
20%
Exhaust system leak between the measurement points altering actual backpressure
15%
Soot or moisture contamination inside the sensor element
7%
Intermittent wiring issue causing occasional signal deviation
Diagnostic Steps
1
Compare exhaust pressure sensor 'A' and 'B' readings at idle and at 2500 RPM — if sensor 'A' reads correctly but 'B' deviates significantly, the fault is isolated to the 'B' sensor circuit.
2
Inspect the pressure sensing hose/tube for partial blockage from soot, condensation, or kinks. Disconnect and blow through to confirm it is clear. Replace if deteriorated.
3
Apply a known pressure to the sensor using a hand pressure pump (0-100 kPa range) and compare the signal voltage to the manufacturer's voltage-to-pressure specification curve.
4
Check for exhaust leaks between the turbo outlet and sensor tap point. Use a smoke machine or soapy water with the engine idling — any leak will skew pressure readings.
5
Clear the code and road test under varying loads. Monitor the sensor response rate — it should change smoothly and quickly with RPM/load changes. A sluggish response confirms sensor or hose degradation.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The exhaust pressure sensor 'B' signal is not tracking within the expected range for current operating conditions, or the sensor response is sluggish and fails performance checks. The ECM compares expected exhaust pressure against actual readings and has found a mismatch. The driver may notice poor ...
The most common cause of P047B (Exhaust Pressure Sensor "B" Circuit Range/Performance) is: Partially blocked pressure sensing hose/tube causing delayed or incorrect pressure readings
Typical repair costs for P047B range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive. Inaccurate exhaust pressure monitoring can lead to improper DPF regeneration scheduling and gradually degrade emissions components. Address within 1-2 weeks.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P047B to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Emissions System
Difficulty
Type
Generic (SAE)
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