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 within specification, procedure is complete. If base timing is not within specification, check for one or more of the following conditions. Repair as necessary.
- Throttle valve is being prevented from fully closing.
- Throttle position sensor is misadjusted (indicated by no continuity between terminals IDL1 and E2 of throttle position sensor connector). See THROTTLE POSITION (TP) SENSOR .
- Valve timing is incorrect (timing belt is not correctly installed).

IGNITION TIMING (Degrees BTDC @ RPM)

Application

⁽¹⁾ Base Timing

⁽²⁾ Controlled Timing

SC400

8-12 @ 650-750

⁽³⁾

⁽¹⁾	Jumper wire connected between terminals TE1 and E1 of DLC No. 1. See Fig 1.

⁽²⁾	Jumper wire disconnected from DLC.

⁽³⁾	Information is not available from manufacturer.

Fig 1: Identifying Terminals Of Data Link Connector (DLC) No. 1

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Ignition Timing: SC400