P0473
UniversalExhaust Pressure Sensor 'A' Circuit High
Medium SeverityThis code indicates that the engine's computer has detected an unusually high voltage signal from the exhaust pressure sensor. This high signal suggests that the exhaust pressure is either abnormally high or the sensor itself is faulty, leading to incorrect readings that can impact engine performance.
⚠️ Before You Begin (Safety First)
Always allow the engine to cool completely before working on exhaust components. Wear appropriate personal protective equipment, including gloves and eye protection. Disconnect the battery before attempting any electrical repairs to prevent accidental shorts or injury.
Common Symptoms
- Check Engine Light illuminated
- Reduced engine power or 'limp mode'
- Poor fuel economy
- Excessive black smoke from the exhaust (especially in diesel engines)
- Engine hesitation or stalling
- Rough idle
Common Causes
- Faulty exhaust pressure sensor
- Clogged Diesel Particulate Filter (DPF) or catalytic converter
- Wiring harness issues (chafed, broken, or corroded wires/connectors) for the sensor circuit
- Vacuum or pressure line blockage or damage leading to the sensor
- Malfunctioning Engine Control Module (ECM), though less common
Frequently reported on: Ford F-Series (diesel models, 2011-2016), Ram 2500/3500 (Cummins diesel, 2010-2015), Chevrolet Silverado/GMC Sierra 2500/3500 (Duramax diesel, 2011-2016), Volkswagen Jetta/Passat TDI (2009-2014)
Diagnostic Steps
- Safely locate the exhaust pressure sensor (often near the DPF or exhaust manifold).
- Inspect the sensor and its electrical connector for any visible damage, corrosion, or loose connections.
- Check the associated vacuum or pressure lines for cracks, blockages, or disconnections.
- If no obvious issues are found, consider replacing the exhaust pressure sensor with a new OEM-quality part.
- Clear the P0473 code using an OBD-II scanner and test drive the vehicle to see if the code returns.
👨🔧 When to Call a Professional
If you have replaced the exhaust pressure sensor and the code P0473 returns, or if you also have symptoms like significant loss of power, excessive smoke, or a strong exhaust smell, it is crucial to seek professional diagnosis immediately as it could indicate a more serious issue like a clogged diesel particulate filter (DPF) or catalytic converter.
Commonly Asked Questions
What is the exhaust pressure sensor and what does it do?
The exhaust pressure sensor measures the pressure within the exhaust system, typically before and after the Diesel Particulate Filter (DPF) or catalytic converter. This data helps the engine's computer monitor exhaust flow and manage emissions control systems, especially DPF regeneration.
Is it safe to drive with a P0473 code?
It is not recommended to drive for an extended period with a P0473 code. While the vehicle may still run, continued operation with incorrect exhaust pressure readings can lead to reduced fuel economy, decreased engine performance, and potentially further damage to the exhaust system or DPF if a blockage is the root cause.
Can a clogged DPF cause a P0473 code?
Yes, a clogged Diesel Particulate Filter (DPF) is a common cause of high exhaust pressure, which can trigger the P0473 code. If the DPF is clogged, the sensor will correctly report high pressure, but the underlying issue is the DPF itself, not necessarily a faulty sensor.
How can I tell if the sensor or a blockage is the problem?
A qualified mechanic can use a diagnostic scanner to monitor real-time exhaust pressure readings. If the readings are excessively high, even with a new sensor, it points towards a blockage. If the sensor readings are erratic or consistently out of specification despite normal exhaust conditions, the sensor is likely faulty.
What happens if I ignore the P0473 code?
Ignoring the P0473 code can lead to persistent Check Engine Light illumination, reduced engine power, poor fuel economy, and potential long-term damage to the DPF, catalytic converter, or even the engine due to excessive back pressure or incorrect fuel management.