LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 1991 >> Corvette Base, 2D Convertible, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Central Control Module >> Self-Diagnostic System >> Entering & Exiting Diagnostics >> Automatic Diagnostic Mode

Automatic Diagnostic Mode

  1. To enter automatic diagnostic mode, ground terminal G of Assembly Line Diagnostic Link (ALDL) connector. See Figure . Turn ignition switch to ON position. CCM will display codes and module associated with code in an automatic code display sequence. CCM is module No. 1 and ECM is module No. 4. See Figure .
  2. During automatic display sequence each code is displayed for 3 seconds followed by a one second pause before displaying next code. A 3 second pause separates code display for each module. After each module code display, "--" will display on speedometer indicating end of display. If a communication problem exists between CCM and ECM, speedometer will display "Err".The particular module being interrogated is indicated on the trip monitor and the codes are displayed on the speedometer. The speedometer also indicates is fault code is current (C) or history (H), respectively. All ECM codes are displayed by CCM as history codes, whether they are current or history.
  3. After all codes are displayed for all modules, trip monitor will display "1.0" and speedometer will be blank. CCM has now entered manual diagnostic mode, waiting for input from the technician.At any time during the automatic code display sequence, the manual mode may be entered by pressing any button on the DIC.
scientia non olet · About LEMON Manuals