P0403 CHEVROLET Exhaust Gas Recirculation Circuit Malfunction

Possible causes
– EGR volume control valve stuck open or closed
– Faulty EGR volume control solenoid valve
– EGR volume control solenoid valve harness is open or shorted
– EGR volume control solenoid valve circuit poor electrical connection
– EGR temperature sensor and circuit
When is the code detected?
An improper voltage signal is sent to Powertrain Control Module (PCM) through the valve
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Possible engine hesitation
P0403 CHEVROLET Description
An Exhaust Gas Recirculation (EGR) system is used in order to lower Oxides of Nitrogen (NOx) emission levels. The EGR system accomplishes this by feeding small amounts of exhaust gas back into the combustion chamber. High combustion temperatures cause NOx. Combustion temperatures are reduced when the air/fuel mixture is diluted with the exhaust gases.
The EGR valve is designed to accurately supply exhaust gases to the engine without the use of intake manifold vacuum. The EGR valve controls the exhaust flow into the intake manifold from the exhaust manifold through an orifice with a Powertrain Control Module (PCM) controlled pintle. The PCM controls the pintle position using inputs from the Throttle Position (TP) sensor, the Manifold Absolute Pressure (MAP) sensor and, the Engine Coolant Temperature sensor. The PCM commands the EGR valve in order to supply the correct amount of exhaust gas recirculation for the current engine operating conditions.
CHEVROLET Technical Service Bulletins for P0403 code
2006 CHEVROLET EXPRESS ENGINE AND ENGINE COOLING:ENGINE
2006 CHEVROLET KODIAK ENGINE AND ENGINE COOLING:ENGINE
2006 CHEVROLET SILVERADO ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET EXPRESS 1500 ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET EXPRESS 2500 ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET EXPRESS 3500 ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET KODIAK ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET SILVERADO 1500 ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET SILVERADO 2500 ENGINE AND ENGINE COOLING:ENGINE
2007 CHEVROLET SILVERADO 3500 ENGINE AND ENGINE COOLING:ENGINE