12 Diagnostic Check Only (Flash Code)
DIAGNOSTIC CHECK ONLY (FLASH CODE)
The PCM will flash Code 12 on the SERVICE ENGINE SOON telltale when it is able to perform diagnostics. The ALDL must be grounded with the key On to flash codes.
* If diagnostics in the PCM are functioning, when the ALDL is grounded Code 12 will flash on the SERVICE ENGINE SOON telltale.
* Code 12 is a flash code. It is not shown on the Scan Tool.