Retrieving Diagnostic Trouble Codes: Notes

Diagnostic Trouble Codes (DTCs) may be retrieved using Lexus scan tool or On-Board Diagnostic (OBD-II) scan tool that complies with SAE standard J-1978. Lexus scan tool or OBD-II scan tool may be operated in NORMAL mode when retrieving trouble codes. If no codes are stored in NORMAL mode, Lexus scan tool may be used in CHECK mode to determine if any first trip DTCs are stored. OBD-II scan tools may be used in MODE 7 (CONTINUOUS TEST RESULTS function) to determine if any first trip DTCs are stored. NORMAL mode is used to retrieve DTCs from Engine Control Module (ECM). MODE 7 or CHECK mode is used to check for DTCs when operating vehicle to simulate conditions in which DTC was set. CHECK mode contains a higher sensing ability to detect malfunctions. CHECK mode helps determine malfunctions caused by poor electrical connections, which are difficult to determine using NORMAL mode.

NOTE: If using Lexus scan tool, when scan tool is switched from NORMAL mode to CHECK mode, all DTCs and freeze-frame data will be erased. DO NOT switch modes until all DTCs and freeze-frame data are recorded.