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  #1  
Old 10-31-2005, 04:53 AM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
1990 California 300se, x92 diagnostic LED

Hi, the check engine light on my car just came on today, and I'm having a problem getting my car to display error codes via its x92 connector. I've followed the instructions from http://mywebpages.comcast.net/chwilka/Error_Code%20_reader_reset_tool.htm as well as those given to others previously in the forums to no avail.

Basically, the LED only lights whenever I press the button on the connector. It never flashes to indicate that no faults are stored, or that there are faults stored. I've even built the simple circuit on the url above and still get the same results. Even following the instructions at http://www.landiss.com/mixture.htm, I could not get the car to go into test mode. The LED wouldn't stay lit!

Does anyone know what might cause this problem or how I can retrieve what error codes have been set? Thanks for any input that you might have!

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  #2  
Old 11-05-2005, 05:26 AM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
Well, I messed around with the button a little more today and found out that I wasn't waiting long enough for the flash to occur. Now what I'm having a problem doing is getting the system into test mode to check the duty cycle, as described on the landiss page.:

Quote:
For California cars, starting in 1988: Press the push button switch on test connector X92 (passenger side, between the two firewalls) for two to four seconds. The LED will flash once, indicating no fault code is stored in the system. Now press the switch again for two to four seconds. The LED will be on continuously, and the injection control is switched over to an on/off ratio output.
As mentioned above, the LED flashes to indicate that no codes are stored (one flash) when I press the button the first time. On the second run, the LED doesn't stay on but instead flashes once again. The cycle continues and I'm unable to get into test mode.
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  #3  
Old 11-06-2005, 06:13 PM
Senior Member
 
Join Date: Jul 2002
Location: visalia ca
Posts: 368
then yer problem is not there, its some other system. need a code reader.

george
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  #4  
Old 11-06-2005, 07:09 PM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
Hi George,

Could you let me know what kind of code reader I would need to get into test mode? I was under the impression that there were only readers for obd2 cars, and that getting into test mode on california cars required some manipulation of the button on the x92 connector.

When I check the voltage between pins 2 and 3 on the x11 connector with KOEO, I get 6v which would indicate around 55% duty cycle. From what I understand, it should be either around 2v (85%) or 4v (70%). Thanks.
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  #5  
Old 11-06-2005, 09:14 PM
Senior Member
 
Join Date: Jul 2002
Location: visalia ca
Posts: 368
Quote:
Originally Posted by alienman
Hi George,

Could you let me know what kind of code reader I would need to get into test mode? I was under the impression that there were only readers for obd2 cars, and that getting into test mode on california cars required some manipulation of the button on the x92 connector.

When I check the voltage between pins 2 and 3 on the x11 connector with KOEO, I get 6v which would indicate around 55% duty cycle. From what I understand, it should be either around 2v (85%) or 4v (70%). Thanks.
i'm gonna hafta look it up now. once you check and clear codes you should
be able to read on/off ratio. my problem is i use the tools so don't do it
this way. but if check engine light is still on then you got another section
thats giving problems and needs code reader to check. not sure if basic one will work but more expensive ones should pull codes.
will check on monday.

george
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  #6  
Old 11-07-2005, 07:26 PM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
Well, I went ahead and checked the duty cycle despite getting 6v (55%) with KOEO. From what I could find out, it should be 70%, 85%, 100% so I'm not sure what's going on with that. The reason why I'm interested in the duty cycle is because the exhaust smells rich, the fuel economy is pretty poor (200 miles on full tank!), and because the previous owner apparently messed with the lambda screw.

Anyhow, once the car warms up, I get a fluctuating reading between 5.5 and 6.5 volts (51-58%). At 2500rpm, I get around 8.5 and 9.5 volts (28-36%). This is a bit out of the "acceptable" 10% deviation, but I haven't adjusted the screw yet because I'd like to make sure that I am in fact checking duty cycle and not something else due to not being able to get into test mode.

Any thoughts, hints, etc would greatly be appreciated. Thanks.
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  #7  
Old 11-08-2005, 09:16 PM
Senior Member
 
Join Date: Jul 2002
Location: visalia ca
Posts: 368
ok, i'm kinda lost but here goes.
when yer light blinks once then hold it down again for 3 seconds
and then you can read duty cycle. after that i don't know.
we use an on/off ratio tester so have no clue as to voltage.
sorry.

george
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  #8  
Old 11-08-2005, 10:46 PM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
Hi, thanks for the info George. I'm going to pick up the $30 Sears multimeter which has been mentioned quite a bit on the forums and see if I get better results with it. Still cheaper than getting someone to look at it
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  #9  
Old 11-09-2005, 05:41 AM
1990 300se
 
Join Date: Oct 2005
Location: Honolulu, Hawaii
Posts: 111
As luck would have it, the check engine light came on this evening. The code I got was 11, but I'm not sure what it means. According to this posting, it could be the air injection system.

I did recently remove a leaking vacuum check valve for the supply to the two thermo-vacuum valves on the fender, but would that cause this code to appear? I thought the purpose of check valves was to prevent leakage, and since there is no leakage on the thermo-vacuum valves, I should be okay until the new check valves come in?

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