EGR Vacuum Booster Check

Fig. 170 SELF DIAGNOSTIC UNIT:

Test mode "3"

- Switch on ignition. Press test button on diagnostic unit 3 times, each time for more than 1 second. Fig. 170.
- LED will commence to flash approx. twice per second.
- E.G.R. vacuum booster should operate in step with flashing of LED. If this occurs, vacuum booster circuit and wiring are intact.

Fig. 171 E.G.R. VACUUM BOOSTER CHECKING:

If E.G.R. vacuum booster does not operate:

- Switch on ignition. Remove vacuum booster connector and measure voltage between terminal 2 and ground, on the connector. Fig. 171.
- If voltmeter does not indicate battery voltage (12 V), check fuse and wifing between ignition switch and vacuum booster.
- Reconnect connector.

Fig. 172 E.G.R. VACUUM BOOSTER CHECKING:

- Switch off ignition.
- Measure resistance between terminals 6 and 15 on control unit connector. Fig. 172.
- If resistance is approx. 85 ohms, (+/- 10 ohms) converter circuit and wiring are intact.
- Repeat test with another control unit.

If resistance is different:

- Check vacuum booster wiring and connections. Measure vacuum booster resistance at vacuum booster connector. Repair or replace as required.