W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
DIAGNOSTIC CODE MEMORY
Diagnostic codes are logged in a list in memory (sometimes referred to as the queue), listing the most recently
occurring code first and logging up to five codes. The codes contained in the list have information recorded as
shown in the table below (codes are examples). Access to the code list position, main code, subcode and active
indicator is through either the shift selector display or the Pro-Link® diagnostic tool. Access to ignition cycle
counter and event counter information is through the diagnostic tool only. Further detail on the use of Pro-Link®
9000 DDR is presented in Appendix G of this manual.
The following paragraphs define the different parts of the code list.
Code List Position. The position which a code occupies in the code list. Positions are displayed as
d1 through d5 (Code List Position #1 through Code List Position #5).
Main Code. The general condition or area of fault detected by the ECU.
Subcode. The specific area or condition related to the main code in which a fault is detected.
Active Indicator. Indicates when a diagnostic code is active. The MODE indicator LED on the shift
selector is illuminated or the diagnostic tool displays YES.
Ignition Cycle Counter. Determines when inactive diagnostic codes are automatically cleared from
the code list. The counter is increased by one each time a normal ECU power down occurs (ignition
turned off). Inactive codes are cleared from the code list after the counter exceeds 25.
Event Counter. Counts the number of occurrences of a diagnostic code. If a code is already in the
code list and the code is again detected, that code is moved to position d1, the active indicator is
turned on, the Ignition Cycle Counter is cleared, and 1 is added to the Event Counter.
CODE READING AND CODE CLEARING
Diagnostic codes can be read and cleared by two methods: by using the Pro-Link® 9000 diagnostic tool or by
entering the diagnostic display mode and using the shift selector display. The use of the Pro-Link® 9000 diagnostic
tool is described in the instruction manual furnished with each tool and briefly in Appendix G of this manual. The
method of reading and clearing codes described in this section refers to entering the diagnostic display mode by the
proper button movements on the shift selector.
Table 51. Code List
Displayed on shift selector and diagnostic tool
d = diagnostic
YES = LED indicator
Not available on shift selector display
SECTION 5 DIAGNOSTIC CODES