Checking Idle Control Valve

Fig. 81 BMW Special Tools For Idle Control System:

Fig. 82 Special Tool Connection Diagram:

***UPDATED BY TSB# 13 03 88 1589, FEB. 88

Special Equipment Required, Fig. 81:
BMW idle control valve current probe,
Digital multimeter (Fluke 8021B, or equivalent)
Exhaust gas analyzer

1. Pull off plug on idle control valve, and check resistance between terminals on the valve at room temp (23 +/- 5°C / 73 +/- 9°F). Resistance should be 9 - 10 Ohms. If test values are not within specification, replace the valve with one of the same value (code number and color code)
2. Connect the idle control valve (ICV) current probe in series with the idle control valve and the harness plug, Fig. 82.
3. Set the multimeter to the 2000 mA range.
4. Connect the multimeter to the ICV current probe.
5. Start the engine (oil temperature should be at least 60°C/140°F)
6. Switch OFF all electrical consumers such as A/C, stereo, rear window defroster, etc.
7. Check the current reading of the ICV with engine at idle. Values should be:
Manual Trans: 460 +/- 5 mA 800 - 900 rpm
Automatic Trans: 460 +/- 5 mA 700 - 800 rpm
8. If the current readings are not within specification, adjust the idle control valve.
a. Turn the adjustment screw on the side of the control valve clockwise (completely closed).
b. Slowly open the adjustment screw until 460 mA and the proper rpm is reached.
Note. Do not turn the adjustment screw too fast as you can easily overshoot the proper adjustment point.
9. Connect an exhaust gas analyzer to make sure the fuel mixture is within specification (0.2 - 1.2%). Adjust mixture as necessary, then readjust the idle control valve.
10. With engine idling at normal operating temp., idle speed should rise to approx. 2000 rpm when the idle valve is unplugged. If not, replace the valve with one of same value (code number and color code).
11. Reconnect the plug on the idle control valve. The idle should drop below the normal speed. If not, replace the valve with one of same value (code number and color code).