Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
CHECK Mode Code Retrieval (Lexus Scan Tool Only)
1998 Lexus GS 300SECTION CHECK Mode Code Retrieval (Lexus Scan Tool Only)
- Ensure vehicle battery is fully charged (at least 11 volts). Apply parking brake. Shift transmission/transaxle into Neutral (M/T) or Park (A/T). Turn A/C and all accessories off. Ensure throttle is in idle position.
- Turn ignition off. Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. DLC No. 3 connector is located under left side of instrument panel. Turn ignition on with engine off. Turn scan tool on.
- Switch scan tool from NORMAL mode to CHECK mode. CHECK mode is operational if MIL on instrument cluster flashes. Start engine. Ensure MIL goes off. Try to simulate conditions of driveability complaint described by customer.NOTE: If ignition is turned from ON to ACC or OFF position, all DTCs and freeze-frame data will be erased. DO NOT switch modes until all DTCs and freeze-frame data are recorded.
- Record any DTCs and freeze-frame data displayed for system diagnosis. If driveability problem exists and no codes are present, go to TESTS W/O CODES article for diagnosis by symptom.
- If any DTCs are present, perform appropriate circuit test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION . For more information on freeze-frame data, see FREEZE-FRAME DATA under INTRODUCTION. For information on 2-trip detection logic codes, see DETECTION LOGIC under INTRODUCTION.
- After repairs for DTC have been completed, DTC must be cleared from ECM memory. See CLEARING DIAGNOSTIC TROUBLE CODES .
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.