5000CD Quattro Sedan (Canada) L5-2226cc 2.22L SOHC Turbo (MC) (1988)
Idle Speed: Testing and Inspection
Fig. 7 Differential Pressure Regulator Test Harness
1.
Start engine and run at idle. Idle speed should be:
750 - 850 rpm (manual transmission)
670 - 770 rpm (automatic transmission, in park or neutral)
2.
With A/C switched ON, idle should increase to 920 rpm.
3.
If idle speed does not increase, check wiring between the injection control unit and the A/C compressor.
4.
If the wiring is OK, connect test harness VW 1315A/1, Fig. 7, between idle control valve and the harness plug.
a. Connect a multimeter to the test harness.
b. Read mA value with A/C OFF, and the engine running at 2000 rpm.
c. Read the meter again with the A/C ON, and the engine still at 2000 rpm.
d. With the A/C switched ON, the current to the idle control valve should be about 80 mA higher.
5.
If the current reading does not change;
a. Check the idle control valve.
b. Check plug terminals for corrosion, burning, or loose connections.
c. Check for power to the A/C clutch.
6.
If all other systems are OK, replace the injection control unit.