ECM Data Displays

While in diagnostic mode, the annunciators on the CCDIC are used to indicate the status of certain system operating status conditions. The different system modes of operation are indicated by the status annunicators turning on or off. A brief summary of ECM status indicators is provided below:

• OFF
  
  Shows the left oxygen sensor rich/lean status. When the OFF light is on, the left oxygen sensor is reporting a "RICH" voltage (above about .60 volts) or an increasing voltage on the rich to lean transition region (from about 0.40 to 0.60 volts). OFF light off indicates a "LEAN", below 0.40 volts or from 0.40 to 0.60 volts and decreasing.
• ECON
  
  Shows the right oxygen sensor rich/lean status. When the ECON light is on, the right oxygen sensor is reporting a "RICH" voltage (above about .60 volts) or an increasing voltage in the rich to lean transition region (from about 0.40 to 0.60 volts). ECON light off indicates a "LEAN" voltage, below 0.40 volts or from 0.40 to 0.60 volts and decreasing.
• AUTO
  
  Shows the OPEN/CLOSED LOOP status of the fuel system. AUTO light on means that the ECM is using CLOSED LOOP fuel control.
• FRONT DEFOG
  
  Shows the ECM's commanded state for the Air Conditioning Compressor Clutch. The ECM receives a request for compressor operation from the BCM on the Data Line. The ECM will allow the clutch to operate given no extreme driving conditions are present (full throttle or high power steering effort).
• DEGREE "C" OR "F"
  
  Shows the status of the transmission third and fourth gear solenoid outputs from the ECM. As the ECM commands third gear the DEGREE "C" indicator illuminates. When the transmission shifts from third gear to fourth gear the DEGREE "F" indicator illuminates. If the transmission is not commanding third or fourth, no indicator will be illuminated. The status light shows the ECM commanded state of the two solenoids. Application of the associated gear is dependent on the integrity of the electrical and hydraulic system.
• REAR DEFOG
  
  Shows the status of the ECM command that turns the VCC solenoid on and off. The REAR DEFOG status light on indicates that the ECM has commanded the VCC electrically on. The status light shows the ECM commanded state. Application of the VCC is dependent on the integrity of the VCC system.
• LOW FAN
  
  Shows the status of the throttle switch. The low fan status indicator is turned on whenever the throttle switch is closed indicating that the ISC motor is controlling idle speed. The light should be on when the throttle is not pushed.
• NORMAL FAN
  
  Shows the status of the Park/Neutral switch. The Norm Fan status indicator is turned on whenever the Park/Neutral switch is closed indicating that the transmission is in Park or Neutral.