Idle air control valve (youcar has air conditioning and it has the 3 pin air control valve that delivers extra air for the engine to maintain designed idle in operating conditions as in gear or air conditioning on that put a bigger load on the engine at idle).
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Mercedes 190 E 2.0 (1983) 102.961 engine
"In giving advice, seek to help, not please your friend." - Solon (638-559 BC) Greek lawgiver & politician.
Idle air control valve (youcar has air conditioning and it has the 3 pin air control valve that delivers extra air for the engine to maintain designed idle in operating conditions as in gear or air conditioning on that put a bigger load on the engine at idle).
My idle control valve has 2 pins. It has new hoses to and from, I check the operation and it clicks with voltage applied, but when I unplug the connector with the engine running it makes no difference and it doesn't click. Could it be the OVP relay???
I don't understand the operation of this part...is it either on or off, or does it open and close partially to control air flow?
Thanks,
Dave
Last edited by slk230red : 09-08-2007 at 07:14 AM.
The circuit for the IACV is here for the two pins valve:
Some basic testing for that:
1. Square iagnstic port 3 and connector 1 at the valve: check for continuity voltmeter positive to pin 2 of the valve coupling and ground, ignition on, 11-14 volts reading. (if not, check or OVP contact 1 is voltage fed at all times, OVP fuse blown, corroded posts, or OVP contact 6/terminal 15 or OVP contact 2/terminal 87 or OVP contact 5/terminal 31 for open circuits)
2. Ignition off, at the boxed diagnostic port check resistance between 3 (minus) and 4 (plus), 20-30 ohms correct range.
3. Checkfor the valve to click if disconnected and apply minus at 1 and plus at 2
4. Square diagnostic port 3 and connector 1 at the valve: check for continuity with the multimeter in ohmmeter mode
5. Square diagnostic port 4 and connector 2 at the valve: check for continuity
6. place voltmeter minus at square diagnostic port 20 and plus at the positive battery post, you should read 11-14 volts or you have no ground
7. Engine at idle, voltmeter on pin 25 at the diagn and minus at the negative battery post. In Park you should have 11-14 volts, secure vehicle with parking brake and in drive voltage should drop (if not neutral switch has gremlins).
8. Check the AC cut signal (engine at idle, AC on) at diag port with a voltmeter with minus at port 2 and plus at port 19... you should have there 11-14 volts or either check further the AC compressor control module (N6) or cable@ pressure switch compressor cutoff (S3 1)
9. Good lucko!
...is it either on or off, or does it open and close partially to control air flow?
That one is the auxiliary air valve (which has a thermocouple and resistor style heating element with an opening/closing disc for the air port).
This particular 2 or 3 electrical one operates electrically only, so, when you've applied 12 volts to it and clicked, it actually had opened fully, and as the engine is either in D or the AC cuts in, the voltage delivered to it dops (on analog testers even to zero, so dealing with small value currents) and the valve closes cutting the extra air for the "park idle" (very useful to operate the engine from cold, ain't it). Also on some models there is too a cut-off signal from the vehicle speed sensor that depends on the vehicle speed to keep the air valve opened only under 1.5 kmph.
Did you cleaned it? The element inside may get glogged.
Linear Mode
