What Does P047D Mean?
The exhaust pressure sensor 'B' circuit voltage exceeds the maximum threshold expected by the ECM. This high signal condition typically indicates a short to voltage, an open signal ground, or a sensor failure. The driver may notice a check engine light and reduced power as the ECM interprets this as abnormally high exhaust backpressure.
Common Causes
30%
Open ground wire in the sensor circuit, causing the signal to float high
28%
Exhaust pressure sensor 'B' internal failure producing maximum voltage output
22%
Signal wire shorted to the 5V reference or battery voltage
15%
Corroded connector causing open-circuit condition on ground pin
5%
ECM internal pull-up or driver circuit failure
Diagnostic Steps
1
Verify the sensor signal voltage in live data — a reading above 4.8V or pinned at 5V confirms the high circuit condition. Normal operating range should stay between 0.5V and 4.5V.
2
Disconnect the sensor and check if the signal voltage at the ECM drops. If it drops to near 0V, the fault is in the sensor. If it stays high, the harness has a short to voltage.
3
Measure the ground wire continuity from the sensor connector to the ECM ground pin — resistance should be less than 1 ohm. An open ground is the most common cause of a high signal.
4
Inspect the connector at the sensor for corrosion, especially on the ground pin. Clean terminals with electrical contact cleaner and apply dielectric grease.
5
If wiring is sound, apply known pressures to the sensor with a hand pump and verify voltage decreases appropriately. A sensor stuck at high voltage regardless of pressure must be replaced.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The exhaust pressure sensor 'B' circuit voltage exceeds the maximum threshold expected by the ECM. This high signal condition typically indicates a short to voltage, an open signal ground, or a sensor failure. The driver may notice a check engine light and reduced power as the ECM interprets this as...
The most common cause of P047D (Exhaust Pressure Sensor "B" Circuit High) is: Open ground wire in the sensor circuit, causing the signal to float high
Typical repair costs for P047D range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive for short trips. The ECM may limit boost pressure or derate the engine as a protective measure. Avoid towing or heavy-load operation until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P047D to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Emissions System
Difficulty
Type
Generic (SAE)
Recommended Tools
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