GM Service Manual Online
For 1990-2009 cars only

This vehicle is equipped with a on-board diagnostic display feature capable displaying and/or clearing DTCs. By selecting specific buttons on the IPC, DTCs are then displayed on the IPC's 20 character display unit. This feature allow DTCs to be read or cleared without the use a scan tool. When the diagnostic mode is first entered, the IPC will enter into an automatic display sequence and will display all systems that communicate on the serial data line. After each system is displayed, the IPC will display the number of DTC(s) (current or history) for that system. The manual diagnostic mode may be selected at any time during the automatic DTC display sequence. In the manual diagnostic mode, you can manually select what module is going to be displayed by pressing specific buttons on the DIC. In this mode, DTC(s) are only displayed for a specific module and will not proceed to the next until requested. Both diagnostic mode displays will also indicates if the DTC is a current DTC (malfunction present now) or a history DTC (malfunction has occurred, but is not present now) with a C or an H, respectively. Diagnostics will automatically be exited if no DIC buttons are pressed for longer than 60 seconds.

Entering On-board Diagnostics

To enter the Diagnostic Display function perform the following steps in order:

  1. Turn ignition ON engine OFF
  2. Press the RESET button to acknowledge any warning messages present.
  3. Press the OPTIONS button on the Driver Information Center (DIC) and hold.
  4. While holding the OPTIONS button press the FUEL button 4 times within a 10 second period.
  5. System will enter automatic display mode.

Operating On-board Diagnostics

    • Automatic -- The automatic mode feature allow you to read each module DTC display function in an automatic display sequence. Each system module DTC will be displayed for 3 seconds followed by a 1 second pause before the next DTC is displayed in an automatic sequence. If no DTC information is sent to the IPC from the system currently displayed on the IPC, the IPC will display NO CODES for that system. At any time during the automatic display function, the manual display feature can be activated by pressing any button on the DIC except the E/M 5 button. The E/M 5 button is used to completely exit the DIAGNOSTICS mode at any time. If there is a communications problem between any system, the IPC will display NO COMM when the IPC is trying to communicate with that system. When all DTC(s) have been displayed for all systems, the IPC will display NO MORE CODES for 2 seconds then will enter the manual display mode, waiting for manual mode operation.
    • Manual -- The manual display feature allows you to manually select each module DTC display function. The manual mode will automatically be entered after the automatic DTC display sequence is complete, or can be entered at any time during the automatic mode by pressing any button on the DIC except the E/M 5 (E/M 5 button is used to exit the DIAGNOSTIC mode at any time). When the manual mode is selected, the IPC will display the MANUAL DIAGNOSTICS mode message for 2 seconds, or until any button on the DIC except the E/M 5 is pressed. After the MANUAL DIAGNOSTICS mode message is displayed, the IPC will display the first system abbreviation and quantity of codes stored for that system, then the IPC will wait for further instructions. To proceed to the next system in the list press the OPTIONS 4 button, and to go backwards in the list press the TRIP 3 button. When a system is selected, each DTC for that system can be read by pressing the GAGES 2 button to move forward in the list, and the FUEL 1 button to move backwards in the list. If no DTC are present for the system currently selected the IPC will display NO MORE CODES and then wait for further instructions. In both diagnostic modes, systems will be displayed in the following order:
       - PCM (Powertrain Control Module)
       - TCS (Traction Control System)
       - RTD (Real Time Damping)
       - BCM (Body Control Module)
       - IPC (Instrument Panel Cluster)
       - RADIO (Radio)
       - HVAC (Heater, Ventilation and Air Conditioning)
       - LDCM (Left Door Control Module)
       - RDCM (Right Door Control Module)
       - SCM (Seat Control Module)
       - RFA (Remote Function Actuation)

DIC Button Functions


Object Number: 173139  Size: MH

The buttons on the DIC provide the following functions:

DIC Button

Function

FUEL 1

Previous DTC

GAGES 2

Next DTC

TRIP 3

Previous System

OPTIONS 4

Next System

E/M 5

Exit Diagnostics

RESET

Clear DTCs