Exhaust Gas Recirculation: Testing and Inspection

Preparation
- Remove vacuum modulator.

Vacuum Modulator Operation:

- Remove modulator cap and filter.
- Clean modulator filter with compressed air.

EGR System Inspection:

- Using a three way connector, connect a vacuum gauge between EGR and modulator.
- Start and idle engine.


VSV Operation
- Check that coolant temperature is below 127° F (53° C).
- Apply parking brake.
- With brake applied, shift vehicle to "D".
- Raise engine speed to 1,400 rpm and note vacuum gauge.

No vacuum present

- Shift transmission back to "PARK".
- Allow engine to reach normal operating temperature.
- Apply parking brake.
- With brake applied, shift vehicle to "D".
- Raise engine speed to 1,400 rpm and note vacuum gauge.

Low vacuum present



Modulator Operation

EGR System Inspection:

- Disconnect vacuum hose from port R of vacuum modulator.
- Using a spare hose, connect manifold vacuum directly to port R.
- Apply parking brake.
- With brake applied, shift vehicle to "D".
- Raise engine speed to 1,400 rpm and note vacuum gauge.

High vacuum present

- Restore all vacuum hoses to original postions and remove gauge.
- If any portion of test failed to provide desired results, refer to testing for that component.