pulse code reader

[mb96]

anyone out there kind enough to send me a diagram of how to build the pulse code reader..My 1990 E300 is showing a CE light..Thank you.

[MRPerformance]

I'd be interested in obtaining a copy of this diagram as well.

///Mike
'93 190E 2.6 Sportline

[300EVIL]

This information was provided by JimF on Mercedesshop. I'm sure he wouldn't mind me giving out his link. I have built one of these and they are very useful. They will not pull up detailed codes however, just the basic ones.

http://pages.prodigy.net/jforgione/MB_X11.html

[stevebfl]

The concept of impulse counting is widely used in Bosch products of that era. It can be monitored with simple tools as described in the DIY article "Evaluating Engine controls". The point to using the tools is one is forced to understand what they are doing.

[mb96]

Hello Steve.

I m suspecting that my O2 sensor is a bad one here. about 9 months back i change the old O2 sensor to the one made for the Ford Mustang. (bad choice i know).
Now that the CE light is on, I was wondering if i can use it to help me dectect that if the O2 is bad.

[stevebfl]

Impulse counting was the earliest form of self diagnostics. As the need for data and actuation became part of the diagnostics they eventually quit communicating faults in this method. For a number f years both forms of communications were used.

In almost all instances impulse counting stopped in 1994 or 1995. Most cars with OBDII will not do any impulse. All OBDII cars from 1996 on do not use any impulse.

The 96 E has full OBDII and a generic OBDII scanner will provide a quantum leap in info over the impulse method. I will still leave a lot out of the complete MB diagnostic package but what is there is significant and way more than impulse alone gives.

[mb96]

This is happening on my 1990 300E Mercedes and not the 96 E320. Thanks

[nthach]

Originally posted by stevebfl

In almost all instances impulse counting stopped in 1994 or 1995. Most cars with OBDII will not do any impulse. All OBDII cars from 1996 on do not use any impulse.

funny that, i was able to extract a P0315 from a 1996 Nissan Quest via impluse and the check engine lamp, by shorting out a diagnostic connector in the engine compartment.

[stevebfl]

I don't consider that a car (bg).

I was of course talking MBs. Must be an interesting flash sequences to do a "P" code!

[Arthur Dalton]

Some of the early Nissan OBD2 systems have dual diagnostic retrieve modes .
The diagnostic mod has a screw that can be turned to mode 1 for flash code ..
How they get it to you is the first 2 digits are long flash and the next 2 digit sequence is short flash..
so, the 0315 is mil light showing a flash code of 3 long flashes followed by 15 short.... the zero understood to complete 2 digits.....ie-03
This is prob only P codes...