11. Exhaust Gas Recirculation (EGR) System Test

11. EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST

Purpose:
The purpose of this test is to check the EGR valve travel positions.

EGR Position
- Ignition ON, engine OFF.
- Use the scan tool to command the EGRVPDES PID.
- Monitor the EGRVP PID to calculate travel.

EGR Valve Position Sensor Approximate Values:

Correct concern causing out of specification values before continuing.

Recommended Procedure:
- Connect the scan tool.
- Ignition ON, engine OFF.
- Access the EGRVP PID and record the closed EGR valve position voltage.
- Access EGRVPDES PID and command the EGR valve from 0% to 100%.
- Record the EGR valve open position voltage.
- Subtract the closed EGR valve position voltage from the open EGR valve position voltage.
- If the valve travel and travel voltage are below specification, install a new EGR valve. Reset the keep alive memory (KAM), refer to Diagnostic Methods, Resetting The keep Alive Memory (KAM). Clear the DTCs. Repeat the self-test. Resetting the Keep Alive Memory (KAM)

Possible Causes:
- EGR control circuit
- EGR valve

Purpose:
The purpose of this test is to check the operation of the intake throttle actuator. A MAP PID change greater than 3 psi is an indication of normal intake throttle actuator operation.

Intake Throttle Position
- Ignition ON, engine running.
- Use the scan tool to command the EGRTP PID.
- Monitor the MAP PID while commanding the EGRTP PID.







Recommended Procedure:
- Connect the scan tool.
- Ignition ON, engine running.
- Access the EGRTP PID and command the intake throttle from open (5%) to close (95%).
- The engine should run normal when the intake throttle is open (MAP PID approximately 14.35 psi), engine may run rough when 85% closed (MAP PID approximately 9.2 psi) and the engine should stall or almost stall when the intake throttle is closed.
- If the MAP PID value does not change more than 3 psi, GO to Pinpoint Test AX. If the MAP PID value changes more than 3 psi, no concern is present. Test AX: Intake Throttle

Possible Causes:
- Intake throttle actuator circuitry
- Intake throttle actuator

Tools Required:
Scan tool