93 300E coding again
 

cleared the codes went for a drive up the coast and the car run excellent, I did feel a light miss at idle.
Now the check engine light came on and the wife mentioned it was idling funny,
socket 8 shows 9 and 13, are this the codes for the O2 sensor going bad? :mad:

What are the CE lamp codes from the DM???

Arthur, i checked the pushbutton and I'm getting 2 flashes, then I checked #8
is that what you meant by DM?

#8 is (ISC) idle speed control malfunction, possible promlems are- wiring/connector/intake leak/throttle valve tight and or sticking, #8 will cause the other codes because its effecting fuel/air ratios

Yes ,
The DM [ Diagnostic Module] is accessed with your built-in Led/SW.
This is the mod that detects Emmissions related faults and trips the CE lamp.
So, anytime you have a CE, you want to go to that DM for codes first.
Pin#8 is the HFM/SFI module and watches ignition/fuel.
Your codes on that indicates O2 sensor is at max lean/rich, so the first suspect is a vac leak [ which will be noticed by your wife complaint of poor idle] or a bad fuel reg . This would be code 13.
The code 9 is an 02 sens code , BUT , if your car has a man. date before 12/92, that code can be displayed without a true fault .
After 12/93, they changed the computer to new version [ 94/95] ] and new parameters. 13 would indicate o2 sensorfault.
The reason for going to DM for codes first is b/c the CE lamp has come on and the code 2 directs you to o2 sensor circuit.. You then go to pin 8 to get a more specific code of that system. In your case , the code 13.
The most common vac leak on 104s is the plastic line crossing the front of the engine to the Switch-Over-Valves , They get brittle and break.
Look there and check all vac hoses..
If you find a leak, reset the Pin 8 , clear DM to get the CE out , and try it.
If no leak, then an O2 sensor test is in order..
Now that you have the tool and are able to get to other modules , it is good to be aware that when a CE lamp comes on , The DM has recieved some fault condition detected by not only its module, but the others too... and if any of the info it recieves from the others will effect the emmissions of the car, it decides to let the owner know by tripping the CE.
So, they all talk to one another , but it is usually the other modules that pick up the faults [ and more specifically so] and the CE/DM has simply recieved some of that info...meaning, it is best for diagnosis to go to the other modules after getting a CE warning
There are other codes from these modules that will never trip the CE , as the DM deems them not Emmissions related .
The point of all this is to let one know that an O2 sensor codes does not mean you need an O2 Sensor, [ altough it might] ..it simply means a fault has been detected in the sensor system...
further test are needed when these codes come up, before true diagnosis can be made..
The advantage of the later OBD2 systems is they are capable of pinpointing O2 sensor faults, but yours will not, as it is OBD1.
ya know what I mean????????

T
He is not getting a code 8. He is referring to PIN 8 on the diagnostic socket box from a prevoius thread.. [ is using a home-made led tool]
Arthur

Thanks for clarifying the DM and codes gathering issue.
My wife also noticed that the gas gauge was very erratic, bouncing as the car was idling poorly, she went and filled the gas tank up but it didn't stop the erratic idling.

I noticed in your reply that you mentioned a fuel regulator as a possible problem, is this the way the fuel regulator going bad shows up? :cool:

NO

The regulator is near the dip stick and has a vac hose attached.
If the hose is leaking , the reg does not work and can pop one of the codes you are getting.
It also can have a leaking diaphram , which lets gas go through the vac line,.
into the engine. Again, popping one of the codes .
Take the vac line off and see if evidence of gas ..should be none.
Look for vac leaks ... as per previous post.