DCL is Data Communincations Link... the communication connection
between the computers in the instrument cluster and the rest of the car.
its usually caused (99% of the time) by a bad connection.
The Data Communications Link (DCL) is a wiring system that allows the sharing of information between the Electronic Engine Control System (EEC-IV) , the Electronic Instrument Cluster (EIC) and external equipment.
The EEC-IV system transmits the following information through the DCL to the EIC:
Engine coolant temperature.
EEC-IV malfunction indication.
The DCL system transmits Malfunction Indicator Lamp (MIL) information to the EIC. The EIC uses MIL information to generate a CHECK ENGINE warning in the event of an engine sensor failure.
The EIC will display the message "CHECK DCL" on its Message Center Display if it is not receiving data from the EEC-IV. This warning is turned off whenever data communication is restored.
The EEC-IV monitors the Data Communication Link for faults. If a fault occurs in data communication a continuous Memory Code is set in the EEC-IV. The DCL Codes (529 for EEC-IV and 533 for EIC) can occur separately or together. These codes are not immediately cleared when data communication is restored.
The existance of a DCL code does NOT mean that a module has failed. also I would check for an oil leak or coolant leak that would be the cause of the smoking under the car.
Check this link for some help on fixing it: http://www.lincolnsonline.com/tech/00086.html