88 560sl check engine light 4 blinks - PeachParts Mercedes-Benz Forum

Premiere_Kirby · #1 07-01-2008, 07:30 AM

Greetings I am a new owner of a nice old 560sl. The check engine light just came on. The car runs fine (good smooth idle, plenty of power etc).
I do have a smell of gas that smells like its running rich but maybe they smell like that when started?

It is orignaly from California & has the push button code reader on the 8 pin diagnostic port. I have read many posts using the search feature but nothing quite solves my issue.

The code I get after holding the button down for a couple seconds is "4 blinks" Does anyone know that code? Also I noticed that this device (pictured) makes a buzzing noise if the car is running & when just the key is on engine off it still buzzes. The part I "think" it looks like is the idle control valve. The idle is at 7,000 rpms at idle with it in gear & 10,000 rpms in park (this seems high eh?)

Thank you for any input.
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mbdoc · #2 07-01-2008, 08:04 AM

That means there is a problem with the air-flow position sensor.

Premiere_Kirby · #3 07-01-2008, 08:24 AM

Thanks, where is that located? I did a search with Air flow position sensor & didnt find much that pertains to a 560. Is this a common issue?

Or is the sensor ok but its picking up a problem elsewhere?

Last but not least is this code of importance for driveability or is it just an emissions code?

sorry for asking so many questions

mbdoc · #4 07-01-2008, 08:57 AM

Air flow position sensor is part of the air flow housing.

That housing is what the fuel distributor is bolted on.

Drive-ability, idle, & stalling are common problems with that code.

Premiere_Kirby · #5 07-01-2008, 11:21 AM

Thanks, I just noticed a crack in the small hose on the air pump. I put a piece of duct tape over the hose to test it. Now the check engine light is off. Could that have been the problem or is it a coincidence that the light went off after using the tape over the cracked hose?

Of Course Im going to replace the hose Im not going to keep driving with tape on it like a butcher.

pimito · #6 07-15-2009, 10:03 AM

Good day to you.
My "Check Engine" indicator of my 1988 560SL came up too (California). I noticed the little red light under the hood. When the engine is idling it just burns. What and how should I check?
Many thanks in advance,
Pim

mbdoc · #7 07-15-2009, 12:03 PM

Press the button for 3-4 seconds to read code & count the number of blinks.
Then press the button for 8 seconds to erase code.

Do that until you get only 1 blink...

pimito · #8 07-15-2009, 02:03 PM

Many thanks for your quick reply!
No 4 blinked 12 times. Is there a table to check what it means?

Thanks again,

Pim

Cal Learner · #9 07-16-2009, 06:45 AM

Quote:

Originally Posted by Premiere_Kirby

Greetings I am a new owner of a nice old 560sl. The check engine light just came on. The car runs fine (good smooth idle, plenty of power etc).
I do have a smell of gas that smells like its running rich but maybe they smell like that when started?

It is orignaly from California & has the push button code reader on the 8 pin diagnostic port. I have read many posts using the search feature but nothing quite solves my issue.

The code I get after holding the button down for a couple seconds is "4 blinks" Does anyone know that code? Also I noticed that this device (pictured) makes a buzzing noise if the car is running & when just the key is on engine off it still buzzes. The part I "think" it looks like is the idle control valve. The idle is at 7,000 rpms at idle with it in gear & 10,000 rpms in park (this seems high eh?)

Thank you for any input.

Check those RPM numbers, they obviously aren't correct. Your photos did not post so can't see what part you're talking about, but if it's IAC valve, I don't think it's supposed to make any noise other than to click once about 5 seconds after turning key on. And if your idle RPMs are significantly above ~750, the IAC may indeed be the problem.

Cal Learner · #10 07-16-2009, 06:53 AM

Quote:

Originally Posted by Premiere_Kirby

Thanks, I just noticed a crack in the small hose on the air pump. I put a piece of duct tape over the hose to test it. Now the check engine light is off. Could that have been the problem or is it a coincidence that the light went off after using the tape over the cracked hose?

Of Course Im going to replace the hose Im not going to keep driving with tape on it like a butcher.

Yes. The EGR/air pump is part of the emissions system that gets reported to the 8-pin diagnostic connector which triggers the CEL.