Exhaust Gas Recirculation: Testing and Inspection
EGR Control System CheckDescription
The engine control module (ECM) controls the EGR valve opening based on the atmospheric pressure, engine speed, engine coolant temperature, intake air temperature and fuel injection quantity. The ECM controls the EGR valve by controlling the EGR DC motor. The EGR valve position is detected by the EGR position sensor, and relayed to ECM .
Condition for running the EGR control:
- The battery voltage is more than 11 volts.
- The barometric pressure is more than 11.6 psi (80 kPa).
- The engine speed is higher than 570 RPM.
- The engine coolant temperature is between 149 °F (65 °C)and 198 °F (92 °C).
- The intake air temperature is between -40 °F (-40 °C)and 185 °F (85 °C).
Condition for canceling the EGR control:
- The barometric pressure went less than 11.3 psi (78 kPa).
- The engine speed dropped below 570 RPM.
- The engine coolant temperature exceeded 203 °F (95 °C), or dropped below 144 °F (62 °C).
- The intake air temperature exceeded 185 °F (85 °C), or dropped below -49 °F (-45 °C).
- Certain DTCs have been set.
EGR Control System Check
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Step 3 - 7:
