Linear EGR System
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
The main element of the system is the linear EGR valve. The EGR valve feeds small amounts of exhaust gas back into the combustion chamber. With the fuel/air mixture diluted by the exhaust gases, combustion temperatures are reduced. The linear EGR valve consists of the following:
- The EGR valve position sensor.
- The EGR valve position sensor cap.
- The bobbin and coil assembly.
- The valve pintle.
- The primary pole piece.
- The armature sleeve.
- The armature and base assembly.
- The exhaust gas inlet port.
- The exhaust gas outlet port.
The linear EGR valve is controlled by a high side driver within the PCM. The high side driver provides 12 volts that is Pulse Width Modulated (PWM) by a duty cycle via the high control circuit of the EGR valve. The ground path is provided by the low control circuit of the EGR valve. The PCM calculates the amount of EGR needed based on the following inputs:
- The Engine Coolant Temperature (ECT) sensor.
- The Intake Air Temperature (IAT) sensor.
- The Barometric Pressure (BARO).
- The Manifold Absolute Pressure (MAP) sensor.
- The Throttle Position (TP) sensor.
- The Mass Air Flow (MAF) sensor.