Rick's Free Auto Repair Advice

Posts Tagged: EGR valve

EGR valve operation

EGR valve operation What is an EGR valve and why does an engine need it? An EGR valve is used on engines to reduce the formation of oxides of Nitrogen (NOx), a key component of smog. NOx causes respiratory issues and is an eye irritant, so reducing it offers critical health benefits to the population. How NOx is formed The air we breathe contains approximately 80% nitrogen, so 80% of the air entering your engine is nitrogen. NOx is formed during the combustion phase when oxygen and nitrogen combine at … Read More

When to replace an EGR valve

What does an EGR valve do and what goes bad? An exhaust gas re-circulation EGR valve reduces pollution by sending a portion of the exhaust gasses back into the engine when the car is cruising at higher speeds. Engines need less fuel when they’re cruising. Since the engine cylinder is a fixed size, it must be filled with either a full dose of air and fuel, or a partial dose of air and fuel and the remainder with something that fills the space but doesn’t burn. Exhaust gas is the … Read More

What is an EGR valve?

What does an EGR valve do and can I delete my EGR? I often see car owners ask how to perform an EGR delete. Doing an EGR delete is a really bad idea. But in order to understand why, I first have to cover, “What is an EGR valve.” What does an EGR valve do? When the EPA first addressed air pollution, they directed their attention to the amount of unburned hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), and oxides of nitrogen (NOx). By adjusting and monitoring air/fuel mixtures, … Read More

P0401 EGR insufficient flow

Fix trouble code P0401 egr insufficient flow – Chrysler Minivan Late model Chrysler Minivans are known to post P0401 egr insufficient flow codes P0401-P0408. The egr valve is like an electronic solenoid that pulls the pintel off its seat. A position sensor at the top of the valve measures how far the pintel shaft has actually moved versus how much the computer commanded it to move. It’s the position sensor that goes bad (see plunger in photo). The problem may be in the sensor, but the fix is in replacing the … Read More


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