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Summary
  • Diagnostic trouble code (DTC) P0476 stands for “Exhaust Pressure Control Valve ‘A’ Range/Performance.”
  • Code P0476 triggers when the powertrain control module (PCM) detects a discrepancy in the signal sent by the exhaust pressure control valve, which generates heat in the form of back pressure in the exhaust to help with cold start warm-up.
  • Common causes of the P0476 code include an exhaust pressure control valve malfunction, a bad PCM, and wiring problems.
  • Common symptoms of the P0476 code include an illuminated check engine light, a lack of power, and poor engine braking.

Too much exhaust back pressure can cause a number of issues. The classic signs of excessive back pressure include a lack of high-speed power, poor fuel economy, and even overheating. Anything that increases exhaust pressure in the engine increases heat. But there are instances when back pressure is needed to warm up your engine during a cold start.

The role of the exhaust pressure control valve is to control exhaust back pressure during cold start warm-up. This valve also opposes cylinder pressure from the engine. P0476 is a trouble code related to a fault in your exhaust pressure control valve. Know more about it through this article.

What Does a P0476 Code Mean?

Diagnostic trouble code (DTC) P0476 stands for “Exhaust Pressure Control Valve “A” Range/Performance. The P0476 code is set once the powertrain control module detects a discrepancy in the signal sent by the exhaust pressure control valve.

See also  P0123 Code: Throttle / Pedal Position Sensor "A" Circuit High

An exhaust pressure control valve is installed in the exhaust stream to generate heat in the form of back pressure in the exhaust to help with cold start warm-up. It can also counteract cylinder pressure coming from the engine cylinders through the exhaust, slowing the engine and the vehicle. This is particularly helpful during towing operations.

Under normal driving conditions, the P0476 code might mean that the incoming signal from the exhaust pressure sensor does not match the intake manifold pressure, ambient air pressure, or preprogrammed information. Depending on the vehicle manufacturer, this could be a mechanical or electrical circuit fault.

For more technical information that can help you better understand P0476, read our discussion about the exhaust backpressure system.

Note: The definition of code P0476 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0476 Code?

  • Exhaust pressure control valve malfunction
  • Bad PCM
  • Wiring problem

What are the Common Symptoms of the P0476 Code?

illuminated check engine light focused
An illuminated check engine light is a common symptom of P0476 code.

How to Diagnose a P0476 Code

P0476 can be set in any vehicle that has an on-board diagnostic system. However, this does not suggest that there is a single diagnostic procedure that will work for all makes and models.  If you lack the necessary technical knowledge, it is best to leave the job to a trusted mechanic.

See also  P0400 Code: Exhaust Gas Recirculation (EGR) Flow Malfunction

How to Fix the P0476 Code

You’ll need the right tools and in-depth knowledge of engine repair to fix the underlying problem that set the P0476 code in your OBD system. If you don’t have the time or the necessary technical know-how for this type of repair, you may be better off taking your vehicle to a certified mechanic.

If you’re determined to find the fix yourself, we recommend consulting your vehicle’s repair manual or looking up vehicle-specific repair information from an online repair database.

About the Exhaust Backpressure System

Code P0476 is most typically used on second generation Ford 7.3L light vehicle diesel platforms. The backpressure control valve is driven by an oil piston built into the base of the turbocharger, and on the second generation 7.3L, a sensor mounted in a small tube connected to the exhaust is used to monitor the pressure.

This is primarily used to control exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The powertrain control module (PCM) uses the measured exhaust back pressure, intake air temperature and engine load to determine the desired exhaust backpressure.

exhaust backpressure system illustration
The powertrain control module (PCM) uses the measured exhaust back pressure, intake air temperature and engine load to determine the desired exhaust backpressure. | Image Source: Richard McCuistian
sensor mounted in a small tube connected to the exhaust
This is the exhaust backpressure sensor, a feedback transducer used by the PCM/ECM that is connected to that small pipe leading to the exhaust. | Image Source: Richard McCuistian

The pipe can become clogged with sludge and carbon, which can set additional codes, but this feedback is used to verify backpressure change when the turbocharger butterfly is commanded closed.

In the photo, a new sensor has been connected to compare static readings for diagnosis purposes. If the backpressure valve system malfunctions so that it remains closed all the time, engine power will be significantly reduced.

See also  P0174 Code: System Too Lean (Cylinder Bank 2)

On the 6.0 Power Stroke, this system was no longer necessary due to the variable geometry turbocharger system, which included the backpressure increase function.

Where to Get a New Exhaust Pressure Control Valve for Your Vehicle

Why put up with the hassles that come with the DTC P0476 when you can clear the code with the right replacement parts? A malfunctioning exhaust pressure control valve is the usual culprit. If you’ve found that it’s what triggered the code in your case, you can count on CarParts.com to have a direct-fit replacement part for your ride.

We make sure to get all our auto parts from trusted manufacturers. Each item is hand-picked by professionals to guarantee quality, so you won’t have to worry about your new exhaust pressure control valve failing you any time soon.

Use our vehicle selector to start shopping for the parts you need. Use the search filters to narrow down the exhaust pressure control valves according to your preferred brand, price range, quantity, etc.

You won’t have to break the bank to get new parts either. Every item in our catalog is set at competitive prices. On top of that, our warehouses are strategically located all over the US to guarantee fast shipping.

Shop now to resolve the trouble code in no time!

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : OBD-II Trouble Codes Tagged With :
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