P047D — Exhaust Pressure Sensor "B" Circuit High

OBD2 code P047D flags a problem with the sensor and actuator circuits (exhaust pressure sensor "B" circuit high). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, corroded, loose or damaged connector, blown fuse feeding the circuit.

powertrain (engine/transmission)

Is it safe to drive?

Prompt diagnosis recommended P047D normally means the control module is receiving an abnormally high voltage from Exhaust Pressure Sensor B; it is not by itself proof of a failed catalytic converter. If the engine runs normally, short trips can be driven while arranging repair, but avoid hard acceleration or sustained boost where fitted. Repair promptly, and stop safely if severe misfire, overheating, strong fuel odor, or major power loss occurs.

Typical symptoms

Check Engine Light illuminated with P047D stored in the powertrain controller.
P047D may be the only noticeable symptom, especially if the engine otherwise runs normally.
Possible hesitation, rough idle, or reduced response during acceleration.
Possible boost-control or engine-limp behavior on vehicles that use the sensor for turbo control.
Unusual fuel-trim or emissions-control operation on engines that use exhaust-pressure feedback.
The engine may enter a reduced-power strategy when the sensor signal is considered implausible.

Common causes

Faulty Exhaust Pressure Sensor B with an internally failed element that produces an abnormally high signal voltage.
Short circuit between the sensor B signal wire and a 5-volt or other constant voltage source.
Corroded, loose, or heat-damaged connector allowing voltage leakage into the sensor signal circuit.
High resistance or an open connection in the sensor B signal, supply, or reference wiring.
Excess voltage on the sensor ground or a poor shared ground that shifts the measured signal upward.
Failed sensor supply or reference circuit in the engine control module.

How to diagnose with an OBD scanner

Confirm P047D and capture the data Connect an OBD2 scanner, such as ELM327 or AIScanAuto, and read stored, pending, and permanent codes. Save the freeze-frame information before clearing anything, and review live Exhaust Pressure Sensor B data if the scanner supports that PID.
Inspect the sensor and wiring Locate Exhaust Pressure Sensor B using the vehicle wiring diagram. With the engine cool, inspect the connector, terminals, sensor body, and nearby harness for corrosion, green residue, damaged insulation, pin pushed back, or heat-related melting.
Test the electrical circuit With ignition on, back-probe the sensor connector and measure supply voltage, ground voltage drop, and signal voltage against manufacturer specifications. A signal pinned near the supply voltage suggests a short; an abnormally low or unstable reading can indicate an open circuit, poor ground, or failed sensor.
Repair the identified fault Repair damaged terminals, corroded connectors, chafed wiring, or an improper ground. If the wiring and supply are correct but sensor B still produces the P047D high-voltage condition, replace that sensor with the specified part and reconnect it cleanly.
Validate the repair Clear the codes with the scanner, complete a road test that includes normal acceleration, and confirm P047D does not return. Also verify that the sensor B reading changes plausibly with engine load and that no new pressure, wiring, or emissions codes appear.

Approximate repair cost

A typical independent-shop estimate for diagnosing and repairing P047D is approximately $200–$900 USD, including connector or wiring repair and replacement of Exhaust Pressure Sensor B when required. Figures are estimates and vary by region, vehicle design, and labor time.

Common questions

Can I safely drive with P047D?

Yes, cautiously if the engine runs normally and there are no warning symptoms. P047D can affect engine or boost control, so avoid sustained high load and schedule diagnosis promptly; stop driving if severe misfire, overheating, or major power loss develops.

Does P047D prove that the exhaust system is blocked?

No. P047D primarily identifies an excessively high electrical signal from Exhaust Pressure Sensor B. A blocked catalyst or other restriction may influence pressure, but it normally produces a different pressure or performance-related code rather than this circuit-high condition.

Where is Exhaust Pressure Sensor B on a P047D vehicle?

It is the exhaust-pressure sensor identified as B by the applicable wiring diagram. It may be mounted before or after a turbocharger or in another exhaust section, so do not assume its position from the letter B alone.

Will resetting P047D fix the fault?

No. Clearing P047D only erases the stored code and does not correct a shorted wire, damaged connector, poor ground, or faulty sensor. If the underlying defect remains, the code will normally return during the next monitoring cycle.

When your check engine light comes on and a scan tool reports P047D, your vehicle's computer has detected a problem with the exhaust pressure sensor "B" circuit. This diagnostic trouble code belongs to the powertrain category, which covers issues affecting the engine and transmission control systems. The specific meaning behind P047D is that the voltage on this circuit is reading higher than it should — essentially, the signal is stuck near battery voltage when it should be fluctuating within a normal operating range.

The engine control unit constantly watches this circuit while you drive. It expects to see the exhaust pressure sensor "B" produce a signal that varies based on driving conditions. When something forces that signal line to stay at full voltage, the module recognizes the abnormality. After running this condition for a set number of drive cycles, the ECU stores P047D and illuminates the malfunction indicator lamp. The freeze frame data captured alongside the code tells you exactly what the engine was doing at the moment the fault appeared — engine speed, load, temperature, and vehicle speed — which gives you a solid starting point for tracking down the root cause.

In practice, a "circuit high" reading on the exhaust pressure sensor "B" circuit usually indicates one of three underlying problems. Either a power feed has accidentally shorted into the signal wire, the ground return path has broken somewhere in the circuit, or the sensor itself has failed in a way that pulls the signal line up to battery voltage. Each of these requires a different repair approach, which is why proper diagnosis matters before spending money on parts.

Symptoms of P047D

The warning signs that accompany P047D tend to be mild to moderate, though they can vary depending on which specific system relies on the exhaust pressure reading:

The check engine light stays illuminated on the dashboard
Some vehicles experience higher fuel consumption than normal
The system that depends on this sensor may work inconsistently or shut down entirely
Certain models will enter limp-home mode, limiting power and speed to protect drivetrain components
Reduced turbocharger performance on turbocharged engines
Erratic or unstable idle in some applications

Common Causes of P047D

The most frequent culprits behind P047D range from simple wiring issues to failed components. These are listed roughly from most to least commonly encountered:

The signal wire has shorted directly to a positive power source
The exhaust pressure sensor "B" has an open ground circuit, preventing proper operation
The sensor itself has failed and is pulling the signal line high
A blown fuse has cut power or ground to the circuit
Wiring elsewhere in the circuit has developed an open or secondary short
The connector at the sensor is corroded, loose, or physically damaged
The control module's driver circuit for this sensor has failed internally
A poor ground connection elsewhere is disrupting the circuit's reference voltage

Diagnosing P047D

Effective diagnosis requires a systematic approach that rules out simple problems before moving to more expensive components:

Connect an OBD2 scanner and confirm that P047D is stored in the ECU. Record the freeze frame data carefully — this snapshot shows the exact engine conditions present when the fault was first detected.
Look for any related trouble codes that might point to a broader electrical problem. Check for manufacturer technical service bulletins that apply to your specific make, model, and model year, as software updates may address known sensor issues.
Perform a thorough visual inspection of the wiring harness and connectors associated with the exhaust pressure sensor "B." Look for signs of chafing, melted insulation, corrosion, or connectors that are not fully seated.
With the sensor disconnected, use a multimeter to check the signal wire at the harness connector. A high voltage reading with the sensor unplugged confirms a short to power somewhere in the wiring. If the voltage drops to normal, the sensor itself is faulty.
Verify that the sensor is receiving proper reference voltage and that the ground circuit is complete and low-resistance.
Perform a wiggle test on the harness while monitoring live data. Any signal dropouts or interruptions suggest broken wires inside the insulation that are not visible on the surface.
After repairs, clear the code and complete a drive cycle that reproduces the conditions captured in the freeze frame. Confirm that P047D does not return.

Repair Options and Costs

Addressing P047D should follow a logical order: tackle the cheapest and most likely issues first, then move to expensive components only when the diagnosis confirms they are at fault.

Repair damaged wiring or corroded connectors: $80–$250
Replace the faulty exhaust pressure sensor "B" or related actuator: $150–$500
Control module diagnosis and repair or replacement: $300–$1,000

Total repair costs for P047D typically fall between $80 and $1,000 depending on which component failed and how much labor was involved. The most common scenario involves either a wiring issue or a failed sensor, both of which are relatively straightforward to fix. Control module problems are comparatively rare and should only be considered after all other possibilities have been ruled out.

Driving Safety Verdict

For most vehicles, P047D does not immediately strand you or make the car unsafe to drive. The engine will continue running, though you may notice reduced performance, poorer fuel economy, or the loss of certain auxiliary functions. Some vehicles will default to limp mode, which limits speed and power but keeps you mobile. However, if the fault is causing severe symptoms like stalling, failure to start, or warnings affecting braking or steering systems, treat the situation as urgent and have the vehicle diagnosed as soon as possible.