Error code on Federal '88 300E

Today my Check Engine light came on twice. When I got home this afternoon, I turned on the ignition without the engine running and read 30% at pin 3. After starting the engine it gave a nice 49%.

A year or two ago MBDoc was kind enough to send me a sheet of paper with the trouble codes. I can't find that sheet of paper anywhere now. It seems like I remember that 30% meant that all was well.

If 30% is a trouble code and someone has the information to tell me what it indicates I would appreciate the help.

Thanks in advance,

The Check Engine light only comes on when engine started when warm.

Thanks for any help you can offer about error code question above.

Have a great day,

[Arthur Dalton]

30% Duty cycle code is :

1- Fault ECT
2- Open/short between ECU/ECT

As it happen when warm, I would try an ECT or Check the connector/sensor w/ohm meter...