Quote:
Originally Posted by gschira
Hey y'all,
Not sure if I should start another thread or not. This is a cps question, but different model. 1988 300SE. I think there are two CPS's, one front- one rear. How do you figure out which one (or both) is causing problems? Thanx for all the great info. This site is awesome....
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You don't say what the problem is. If it's a hard start, rough idling, stalling type problem, it's the hefty 4-prong CPS at the back of the cylinder head. That component is actually 2 identical resistors enclosed in a single case. One resistor is for KE controller (fuel management) and the other is for EZL controller (ignition management). That sensor can be tested with an Ohmmeter by measuring on diagonal pins and the result compared to a temperature chart (look in the archives).
The front CPS is not involved in engine operation, but is used for diagnostic purposes, or so I've been told. It supplies the so-called TD signal to the X11 diagnostic connector.