check engine light
 

My 89 560 sel check engine light stays on all the time. Which pins do I use on the jack to retreive the code, and do I use the same pins to clear it? It's the only light on, so I was wondering if there were any usual suspects that make it come on. Thanks,
Chris

The diagnostic connector x11 on the left fender only gives duty-cylce codes and will read right when the system is right.

The diagnostic connector x92 on the right side will give engine codes through pin #3. Look at the DIY article "Evaluating engine controls" to see how to read both style codes and how to erase impulse codes.