Ensure engine is at normal operating temperature. Connect timing light magnetic pick-up to spark plug wire for cylinder No. 6. Connect tachometer test lead to terminal IG- of DLC. See Fig 1. Connect jumper wire between terminals TE1 and E1 of DLC.
Ensure idle speed is within specification. See IDLE SPEED SPECIFICATIONS table under IDLE SPEED & MIXTURE. Check base timing. Ensure base timing is within specification. See IGNITION TIMING table. If base timing is not within specification, ensure throttle valve is fully closed, continuity exists between terminals IDL and E2 of throttle position sensor, and valve timing is okay. See Figure. Procedure is complete.

IGNITION TIMING

Application

Base Timing ⁽¹⁾

⁽²⁾ Controlled Timing

ES300

10 @ 650-750

10-20 @ 650-750

GS300

10 @ 650-750

8-12 @ 650-750

LS400

8-12 @ 600-700

⁽³⁾

SC300

Auto. Trans.

10 @ 600-700

9-11 @ 600-700

Man. Trans.

10 @ 650-750

9-11 @ 650-750

SC400

8-12 @ 650-750

⁽³⁾

⁽¹⁾	Jumper wire connected between terminals TE1 and E1 of DLC. See Fig 1

⁽²⁾	Jumper wire disconnected from DLC.

⁽³⁾	Information is not available from manufacturer.

Fig 1: Identifying Data Link Connector (DLC) Terminals

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.

Safety Warning

LS400 & SC400