'94 Taurus 3.0l trouble code 411


Old 04-30-05, 01:05 PM
Thread Starter
Join Date: Sep 2004
Posts: 238
'94 Taurus 3.0l trouble code 411

KOER code 411 cannot control low rpm self test

I took off and cleaned with carb cleaner idle air control valve. It looked just like the one in the box at Auto Zone. The plunger inside was about half open with the solenoid de-energized. The resistance across the solenoid is within spec. I did not buy the part.

There does seem to be a high-pitched whistle at the throttle plate, but it may have always done it. I donít know, since this is the first time I had reason to hunt for a vacuum leak on this car.

The car seems to idle too fast and the idle really sounds like it drops when shifted into gear. Reverse is always accompanied by a big thump. I donít know notice any other drivability problems.

Any ideas?
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Old 05-05-05, 05:29 PM
Jason R's Avatar
Join Date: Jun 2002
Posts: 261
Sounds like a vacuum leak to me.
Old 05-06-05, 09:24 AM
Thread Starter
Join Date: Sep 2004
Posts: 238
slower idle

Yesterday it spontaneously started idling much slower, so a bug or some crud must have been sucked into the source of the vacuum leak.

For grins, I pulled the codes again. This time I get KOER 412 followed by the 411. So now, the car cannot control the high and low range idles on the self-test.

Last night, I unplugged the idle air valve electric, which made no difference on idle. In addition, I checked the harness and I was getting batt. voltage to the valve.
Old 05-06-05, 09:35 AM
Join Date: Dec 2001
Posts: 2,538
sounds like a bad iac valve the idle should drop when you disconnect the iac to a very low base idle around 600 rpm, you can remove the valve and block off the holes with your hand while having someone start the vehicle if it now idles very low if not at all you do not have a vacum leak if it still idles high you probably have a vacum leak or the base idle screw has been misadjusted.
Old 05-06-05, 10:44 AM
Thread Starter
Join Date: Sep 2004
Posts: 238
self-healing vacuum leak

I 'll check tonight.

Is it possible to have a vacuum leak one day and not the next?


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