Basic Operation - On Board Diagnostics

BCM Diagnostics:

DESCRIPTION:

The Diagnostic procedures outlined are controlled by the ECC panel buttons. The procedure number refers to the number next to the box in the system flow chart. A description of each step is provided as a diagnostic aid. The service mode diagnostics is used to view various input and output values seen by the ECM, BCM, and the IPC. It will also perform diagnostic functions such as SNAPSHOT, and has the ability to clear any BCM or ECM codes stored in the computer systems memory. Also refer to "ECM STATUS LIGHTS," and "BCM STATUS LIGHTS"

1. ENTER DIAGNOSTICS: Self diagnostics is entered by simultaneously pressing the "OFF" and "WARM" buttons on the ECC panel for 3 seconds.

2. FULL SEGMENT CHECK: The Full segment check is automatically performed after self diagnostics are entered. This test will illuminate all the segments on the ECC panel to test their integrity, if any of the segments do not light the ECC panel will have to be repaired before further diagnostics are performed.

3. ECM CODE DISPLAY: After the full segment check takes place the BCM will then display any ECM codes that are stored in memory. The codes will be displayed on the IPC panel and will begin with the lowest numbered codes first.

4. BCM CODE DISPLAY: BCM codes are displayed directly after ECM codes. Any BCM codes that are stored in memory will be displayed on the ECC panel.

5. ECM?: After the BCM codes are displayed the IPC panel will display "ECM?." This is the prompt that will be selected if you desire to receive ECM DATA, ECM INPUTS, ECM OUTPUTS, ECM OVERRIDE, CLEAR CODES, OR SNAPSHOT on the ECC panel. To bypass the ECM MODE press the fan down (LO) button on the ECC panel. To select the ECM MODE press the fan up button (HI). If you press "HI" when "ECM?" is displayed, the IPC will now display "DATA?." If you do not which to view ECM data you may scroll through other items by pressing "LO" until the desired item is displayed then press "HI" to view that item. When "DATA," "INPUTS," or "OUTPUTS" are selected for viewing, they are represented by an I.D. code and the value of the input or output device. The first two characters are letters which identify the system and test type (i.e. ED for ECM DATA) and the last two characters identify the test i.e. ED01 for throttle position). For a complete list of device numbers refer to the appropriate screen for the item selected, i.e. "ECM DATA DISPLAYS." When "OVERRIDE," "CLEAR CODES," OR "SNAPSHOT" is selected refer to the appropriate screen for the use of these functions.

6. BCM?: This is the prompt that will be selected if you desire to receive BCM DATA, BCM INPUTS, BCM OUTPUTS, BCM OVERRIDE, CLEAR CODES, OR SNAPSHOT on the IPC panel. To bypass the BCM MODE press the fan down (LO) button on the ECC panel. To select the BCM MODE press the fan up button (HI). If you press "HI" when "BCM?" is displayed, the IPC will now display "DATA?." If you do not which to view BCM data you may scroll through other items by pressing "LO" until the desired item is displayed then press "HI" to view that item. When "DATA," "INPUTS," or "OUTPUTS" are selected for viewing, they are represented by an I.D. code and the value of the input or output device. The first two characters are letters which identify the system and test type (i.e. BD for BCM DATA) and the last two characters identify the test i.e. BD21 for coolant temperature). For a complete list of device numbers refer to the appropriate screen for the item selected. When "OVERRIDE," "CLEAR CODES," OR "SNAPSHOT" is selected refer to the appropriate screen for the use of these functions.

7. IPC?: IPC inputs may be displayed by pushing "HI" when the "IPC" prompt is displayed then selecting "HI" when the "INPUTS" prompt is displayed. Refer to "IPC INPUT DISPLAY" for operation of this function.

NOTE: Diagnostics can be exited at any point by pressing the BI-LEV button on the ECC panel. To proceed with diagnostics press the indicated ECC buttons.