Reading and Clearing Diagnostic Trouble Codes
PCM/ECM
To clear ECM/PCM trouble codes enter diagnostics. After the segment check and the codes are displayed, select the ECM/PCM system level by pressing the "HI" button, then press the "LO" button to select the "CLEAR CODES?" test type. When "CLEAR CODES?" is displayed, push the "HI" button and the ECM/PCM codes will be cleared.
BCM
To clear BCM trouble codes enter diagnostics. After the segment check and the codes are displayed, push the "LO" button to select the BCM system level, when "BCM?" is displayed, press the "HI" button, then press the "LO" button to select the "CLEAR CODES?" test type. When "CLEAR CODES?" is displayed then push the "HI" button and the BCM codes will be cleared.
NOTE: If ECM/PCM codes are cleared at any time, snapshot code information will be lost. On-board diagnostics cannot be used to clear SIR code 51, refer to TSB bulletin #91-I-20 12/90.