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.
Air Assist System
1998 Lexus SC 300SECTION Air Assist System
- Ensure engine is at normal operating temperature. Ensure idle speed is 650-750 RPM. Ensure transmission is in Neutral. Turn A/C off. Connect Jumper Wire (09843-18020) between terminals TE1 and E1 of DLC No. 1. See Figure.
- Increase engine speed to about 900-1300 RPM for about 10 seconds. Release throttle. Engine speed should decrease to idle speed of 650-750 RPM. Stop engine. Disconnect air hose from air pipe. See Figure. Plug hose end, and cap off the hose pipe fitting.
- Start engine. If engine idles at about 500 RPM or less (or if engine stalls), air assist system is okay. If engine does not operate as specified, check and repair vacuum leak.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.