How to Fix OBD-II Code P0474: Exhaust Pressure Sensor Intermittent

Medium 1-2 hours Medium Severity Verified June 2026
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Error Code
P0474
Brand
OBD-II Generic
Product Type
automotive
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours
OBD-II code P0474 indicates that the engine control module (ECM) detects an intermittent or erratic signal from the exhaust back pressure sensor. This sensor monitors exhaust pressure and helps manage emissions. The issue is often caused by a faulty sensor, wiring problems, or a blocked pressure line.
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Tools You'll Need

How to Fix Error Code P0474

  1. Scan and Clear the Code

    Ensure the vehicle is parked safely and the engine is off when connecting the scanner.

  2. Inspect the Exhaust Pressure Sensor

    Let the engine cool completely before touching exhaust components.

  3. Check Wiring and Connector

    Do not probe wires with the engine running unless instructed.

  4. Test the Sensor

  5. Check the Exhaust Pressure Line

    Be careful of hot exhaust components.

  6. Replace the Sensor if Faulty

    Use proper tools to avoid damaging threads.

Parts You May Need

Exhaust back pressure sensor
Check Price on Amazon
Exhaust back pressure sensor
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Exhaust back pressure sensor
Check Price on Amazon
Exhaust back pressure sensor
Check Price on Amazon
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When to Call a Professional

If the code persists after checking wiring and replacing the sensor, or if you lack the tools or experience to test electrical components, consult a professional mechanic. Common wiring issues requiring specialized equipment may also warrant professional help.

Frequently Asked Questions

Can I drive with a P0474 code?
You may notice reduced fuel economy or performance. It is safe to drive short distances, but you should diagnose and repair the issue soon to avoid further damage or failed emissions tests.
What does the exhaust pressure sensor do?
It measures exhaust backpressure and sends data to the ECM to optimize EGR operation and emissions. An intermittent signal can cause rough idle, poor acceleration, or a check engine light.
How much does it cost to fix P0474?
The sensor itself costs $30–$100. Labor can range from $100–$200 if done by a mechanic. DIY costs are lower, around $50–$150 total.
Is P0474 the same as P0470?
No. P0470 indicates a general sensor circuit malfunction, while P0474 specifically indicates an intermittent signal. However, the diagnosis is similar.
Can a clogged exhaust cause P0474?
Yes, a clogged exhaust (e.g., from a blocked catalytic converter or muffler) can cause erratic pressure readings. Check for exhaust restrictions if the sensor and wiring are fine.

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