System Check - EGR

EGR System Check (With Linear EGR Valve):

Exhaust Gas Recirculation (EGR) System Circuit:

CIRCUIT DESCRIPTION
To control Exhaust Gas Recirculation (EGR), the Powertrain Control Module (PCM) operates the linear EGR valve. The linear EGR valve is a small motor with a pintle that is normally closed. By providing a ground path, the PCM will open the pintle and allow exhaust gasses to pass through the valve. The PCM control of the EGR is based on the following inputs:

^ Engine coolant temperature - above 25°C (77°F)
^ Throttle Position (TP) - "OFF" idle.
^ Manifold Absolute Pressure (MAP).
^ Intake Air Temperature (IAT), if equipped.
^ Barometric Pressure (BARO).
^ Park, Reverse, Neutral, Drive, Low (PRNDL) position switch.
^ Pintle position sensor.

If Diagnostic Trouble Code (DTC) 23 is stored, refer to Diagnostic Trouble Code Charts/DTC 23 Intake Air Temperature Sensor Circuit. Powertrain Controls - ECM/PCM
If DTC 32 is stored, refer to Diagnostic Trouble Code Chart / DTC 32 Exhaust Gas Recirculation Circuit. DTC 32

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart:

1. At idle, the EGR valve should not be open greater than 3%. A misadjusted Park/Neutral Position (PNP) switch or the EGR valve stuck open will allow exhaust gasses to enter the combustion chamber and create a rough idle condition.
2. Checks the pintle's ability to be manually commanded to the desired positions.
3. Checks the electrical circuit of the EGR valve and connecting components.
4. Checks for plugged EGR passages or a faulty EGR valve.