Without Scan Tool

Flash code diagnosis can only be used to identify diagnostic trouble codes in the EBCM history. The flash code diagnostic mode cannot be initiated if the Anti-Lock warning lamp is illuminated steadily.

Several diagnostic trouble codes can only be read using the TECH 1 diagnostic computer. If these diagnostic trouble codes are present as history diagnostic trouble codes only, they can be read through flash code diagnosis.
To initiate flash code diagnostics, proceed as follows:

1. Ground pin "H of the diagnostic connector, then place ignition switch in On position. Flash code diagnostics will remain on as long as pin "H" is grounded, serial data line communication has not been initiated, and vehicle speed is less than 4 mph.
2. Approximately three seconds after pin "H" has been grounded, the EBCM will begin flashing the Anti-Lock Indicator Lamp in flash code sequence. Observe and record flashes, noting the following:
a. The flash code sequence, Fig. 57, will begin with Diagnostic Trouble Code 12 flashing three times to signal the beginning of the diagnostic trouble code display.
b. Each stored diagnostic trouble code will than be flashed three times. After all diagnostic trouble codes have been displayed, the sequence will repeat, starting with Diagnostic Trouble Code 12.
3. Refer to Intermittent And Poor Connection Interpretations for further information regarding specific diagnostic trouble codes. Diagnostic Strategies