What causes fault code P047A?

• Most likely: Faulty Exhaust Pressure Sensor B (internal short or open circuit) • Likely: Damaged wiring harness or corroded connectors • Possible: Clogged or leaking pressure tube/hose between exhaust manifold and sensor • Rare: Faulty Engine Control Unit (ECU)

How do you fix fault code P047A?

STEP 1: Visually inspect connector 'B' for corrosion or bent pins. Check the pressure hose/tube for cracks or carbon buildup. STEP 2: Using a multimeter, verify 5.0V reference voltage and a solid ground with ignition on. Monitor signal voltage (should fluctuate with RPM). STEP 3: Perform a continuity test on signal wires back to the ECU (resistance should be < 1 Ohm). STEP 4: Replace the sensor if it fails electrical tests. Clear codes and perform 'adaptation reset' if required by the manufacturer.

Powertrain (Engine & Gearbox)Standard EOBD

P047A - Exhaust Pressure Sensor B - Circuit Malfunction

Q: What does fault code P047A mean?

P047A is a generic OBD-II diagnostic trouble code indicating a malfunction in the Exhaust Pressure Sensor 'B' circuit. This sensor monitors the exhaust backpressure, which is critical for VGT/VNT turbocharger control and Diesel Particulate Filter (DPF) monitoring. The ECU monitors the voltage signal (typically a 0-5V scale); if the signal is erratic, open, or shorted, the ECU will store this code and may trigger Limp Mode to prevent engine or turbocharger damage due to incorrect boost pressure regulation.

Q: What are the symptoms of fault code P047A?

• Check Engine Light (MIL) illuminated • Reduced engine power (Limp mode) • Erratic turbocharger boost behavior • Increased fuel consumption • Regeneration issues with the DPF

Last updated:1 February 2026

Related:Avgastryckgivare B, Turbocharger, Diesel Particulate Filter (DPF), Engine Control Unit (ECU), Sensor Wiring Harness

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0400

Exhaust Gas Recirculation Flow Malfunction

P0401

Exhaust Gas Recirculation (EGR) Flow Insufficient Detected

P0402

Exhaust Gas Recirculation Flow Excessive Detected

P0403

Exhaust Gas Recirculation (EGR) Control Circuit

Technical Description

P047A is a generic OBD-II diagnostic trouble code indicating a malfunction in the Exhaust Pressure Sensor 'B' circuit. This sensor monitors the exhaust backpressure, which is critical for VGT/VNT turbocharger control and Diesel Particulate Filter (DPF) monitoring. The ECU monitors the voltage signal (typically a 0-5V scale); if the signal is erratic, open, or shorted, the ECU will store this code and may trigger Limp Mode to prevent engine or turbocharger damage due to incorrect boost pressure regulation.

Possible Causes

Faulty Exhaust Pressure Sensor B (internal short or open circuit)

Damaged wiring harness or corroded connectors

Clogged or leaking pressure tube/hose between exhaust manifold and sensor

Faulty Engine Control Unit (ECU)

Symptoms

Check Engine Light (MIL) illuminated

Reduced engine power (Limp mode)

Erratic turbocharger boost behavior

Increased fuel consumption

Regeneration issues with the DPF

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P047A - Exhaust Pressure Sensor B - Circuit Malfunction

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P047A - Exhaust Pressure Sensor B - Circuit Malfunction

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