PocketLOGGER for DSMs can read 16 different error codes. The basic meaning of the error is displayed on the PDA screen. We do not provide support for tracking down what caused the error to be tripped. You can post your question in our user forum.
Pressing the "Clear Error" button in PocketLOGGER will clear the errors and turn off the Check Engine light, as long as the condition that caused the error no longer exists.
Stored errors don't go away when "Clear Errors" is pressed:
1990 ECUs do not support clearing the errors in this manner. You must remove power to the ECU for 10 seconds to clear the errors.
PocketLOGGER shows a lot of errors stored, but my Check Engine light isn't on:
You must have the ignition on in order to read error codes. There is no error correction in the DSM protocol and the PocketLOGGER is picking up noise that it thinks are stored error codes. Make sure the ignition is on, the cable is powered and restart the software.