EGR not incomplete/OBD II?

Hello, and thanks for your question!

Is the check engine light on? Any codes present would give us clues as to how to combat the problem. The EGR readiness monitor will not be complete until it meets every criteria for your particular system. Please see below the details regarding your particular system, and take note that this system requires 12 ignition cycles before the PCM makes the decision to indicate a problem is present.

LINEAR EGR CONTROL
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

EGR DIAGNOSTICS
The PCM tests the EGR flow during deceleration by momentarily commanding the EGR valve to open while monitoring the signal of the manifold absolute pressure (MAP) sensor. When the EGR valve is opened, the PCM will expect to see a predetermined increase in MAP. If the expected increase in MAP is not detected, the PCM records the amount of MAP difference that was detected and adjusts a calibrated fail counter towards a calibrated fail threshold level.

When the fail counter exceeds the fail threshold level, the PCM will set a Diagnostic Trouble Code (DTC).

Normally, the PCM will only allow one EGR Flow Test Count during an ignition cycle. To aid in verifying a repair, the PCM allows twelve EGR Flow Test Counts during the first ignition cycle following a code clear or a battery disconnect. Between nine and twelve EGR Flow Test Counts should be sufficient for the PCM to determine adequate EGR flow and pass the EGR flow test. If the PCM detects an EGR flow error, a DTC will set.

The PCM monitors the position of the EGR valve pintle via the EGR position sensor. If the PCM detects a calibrated variance between the Desired EGR Position parameter and the EGR Position Sensor parameter, actual position, for a calibrated amount of time a DTC will set.

The PCM also monitors the EGR solenoid high control circuit EGR solenoid low control circuit for electrical faults. If an EGR control circuit fault is detected for a calibrated amount of time a DTC will set.

Let us know,
William

Hello, thanks for your reply!

If there are no codes and no check engine light present, the PCM has not detected a problem with the EGR system. Are you checking this before or after driving? I would leave the scan tool plugged in while driving and see if it changes eventually. You may have to stop the car and start it again. But as stated above, the computer will go through the necessary checks every time, and it will only do these checks during a drive cycle, not while idling.

Also, what kind of scan tool are you using?

Let us know,
William

Hello,

If there are no codes present or drivability issues, I wouldn't say that there is a problem. The PCM will do the necessary checks every time the car is driven and set a DTC when a problem is detected. Keep in mind the PCM will count 12 drive cycles before deciding to set a DTC following a computer code clear or repair.

You can also check the inputs from these components and make sure they read normally - 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.

Let us know what you find,

William

No problem, and thanks for using 2CarPros.

William

No problem, very glad to hear!

Thanks for using 2CarPros, we are always here to help.

William