DTC P1404: EGR Valve Closed Pintle Position: Description

WARNING: This page is about a different car, the 2001 GMC Savana, 2001 Chevrolet RV Cutaway, 2001 Chevrolet Cutaway, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

An Exhaust Gas Recirculation (EGR) system is used in order to lower Oxides of Nitrogen (NOx) emission levels caused by high combustion temperatures. EGR accomplishes this by feeding small amounts of exhaust gases back into the combustion chamber. When air/fuel mixture is diluted with exhaust gases, combustion temperatures are reduced. A linear EGR valve is used on this system. The linear EGR valve is designed to accurately supply exhaust gases to engine without use of intake manifold vacuum. The valve controls exhaust flow going into intake manifold from exhaust manifold through an orifice with a control module controlled pintle valve. Powertrain Control Module (PCM) commands EGR by applying a 12-volt duty cycle to EGR valve. This can be monitored on a scan tool as desired EGR position. PCM can monitor pintle position with EGR pintle position signal. This sensor uses a variable resistor with a 5-volt reference, a signal circuit, and a ground. Signal circuit monitors changes in voltage on variable resistor as pintle moves.