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DTC codes / P04xx · Auxiliary emission controls / P0473

P0473Exhaust Pressure Sensor High

P0473 means the powertrain control module (PCM) has detected a voltage signal from the exhaust pressure sensor that is higher than the normal operating range for the current engine conditions. The sensor is typically used to monitor exhaust backpressure, often for turbocharger control or diesel particulate filter (DPF) monitoring, and a high signal indicates either excessive actual pressure or a fault in the sensor circuit.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Reduced engine performance or limp mode, especially under load
  • Poor fuel economy or increased regeneration frequency on diesel engines
  • Black smoke or excessive exhaust smoke under acceleration
  • Turbocharger-related symptoms such as low boost or overboost
  • In rare cases, a noticeable exhaust leak or restriction sound

Common causes, most likely first

  1. Faulty exhaust pressure sensor or sensor element contaminated with soot
  2. Clogged or restricted exhaust pressure sensor tube or port
  3. Wiring issue such as a short to voltage or high resistance in the signal circuit
  4. Exhaust restriction, such as a blocked DPF, catalytic converter, or muffler
  5. Turbocharger wastegate or variable geometry turbo (VGT) malfunction causing high backpressure
  6. PCM internal fault or corrupted sensor reference voltage
  7. Incorrect sensor installation or damaged connector pins

How to diagnose and fix it

  1. Use a scan tool to read live data from the exhaust pressure sensor and compare it to key-on, engine-off and idle values to verify the high reading.
  2. Visually inspect the sensor, connector, and wiring for damage, corrosion, or loose pins, and check for technical service bulletins (TSBs) for the specific vehicle.
  3. Check the sensor tube and port for blockage or soot buildup, and clean or replace as necessary.
  4. Perform a voltage drop test on the sensor signal circuit and reference circuit to rule out wiring faults.
  5. Test the sensor with a known-good unit or use a pressure gauge to verify actual exhaust backpressure against the sensor reading.
  6. If the sensor and wiring are good, check for exhaust restrictions by measuring backpressure before and after the DPF or catalytic converter.
  7. Repair or replace the faulty component, clear the diagnostic trouble codes (DTCs), and verify the repair with a test drive.

Common misdiagnosis traps for P0473

  • A high exhaust pressure reading often results from a clogged sensor tube rather than a failed sensor, so cleaning the tube can resolve the code without parts replacement.
  • On diesel vehicles, a P0473 can be set by a failing DPF that is genuinely restricted, and replacing the sensor alone will not fix the underlying issue.
  • Wiring harness chafing near hot exhaust components can cause intermittent shorts to voltage, mimicking a sensor failure and leading to unnecessary sensor replacement.
  • Some vehicles use the exhaust pressure sensor for turbocharger control, so a high signal may cause drivability issues that are misattributed to the turbo itself.
  • The PCM may set P0473 in conjunction with other codes like P0470 or P0471, and diagnosing all codes together prevents overlooking a shared circuit fault.

Can I keep driving with P0473?

It is generally safe to drive with P0473 if the vehicle runs normally, but avoid heavy acceleration or towing until the fault is diagnosed. If the engine enters limp mode or performance degrades significantly, seek professional diagnosis promptly to prevent damage to the turbocharger or exhaust system.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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