Manual Operation Of Self-Diagnostics: Override

NOTE: If directed here from TEST TYPE SELECTION under MANUAL OPERATION OF SELF-DIAGNOSTICS in this article, go to step 2).

Override tests facilitate the display of a component's current operational status, represented as a percentage of its full range. Override tests also permit a component's present functional status to be overridden and technician controlled. To enter override, complete the following:
- Enter self-diagnostics. See ENTERING SELF-DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM in this article.
- Display trouble codes stored in memory. See DISPLAYING TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in this article.
- Select BCM or ECM system for testing. See STEP 1: SYSTEM SELECTION under MANUAL OPERATION OF SELF-DIAGNOSTICS SYSTEM in this article.
- Select OVERRIDE test. See STEP 2: TEST TYPE SELECTION under MANUAL OPERATION OF SELF-DIAGNOSTICS in this article.
After selecting OVERRIDE proceed to selecting a specific override test. See STEP 3: SPECIFIC TEST SELECTION under MANUAL OPERATION OF SELF-DIAGNOSTICS in this article. Upon completion of specific test selection, return to this section and proceed to step 3).
The display will now alternate between the selected system's present operating specifications and the specifications that would be normal for the particular system. All values for comparison are displayed on the ECC panel.
Pressing the WARMER or COOLER buttons on the ECC panel begins the override function, while simultaneously stopping the alternate display of present and normal system operating values. Pressing WARMER button increases a value. Pressing COOLER button decreases value.
Upon releasing the COOLER or WARMER button, the display may remain at an override value or automatically return to normal program control. If the display remains at the override value, normal program control can be resumed as follows:
- Selection of another override test will cancel the current override.
- Selection of another system will cancel the current override.
- Overriding a value beyond the extreme of 0 or 99 will cause display to alternate between the out-of-range value and the opposite extreme. If button (cooler or warmer) is released while the out-of-range value is displayed, normal program control will resume.

NOTE: While in override, another test type within the selected system may be active at the same time. After selecting an override test, pressing OFF button on the ECC selects another test type. The ECC panel will, however, continue to display the selected override. Pressing WARMER or COOLER button on the ECC makes it possible to monitor the effect of the override on different vehicle parameters.