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.
Sub-Throttle Position (Sub-TP) Sensor: Adjustment
- Disconnect sub-TP sensor connector. Loosen sub-TP sensor mounting screws. Remove sub-throttle actuator. Ensure sub-throttle valve is fully closed and sub-throttle valve gear is touching stop screw. Insert feeler gauge between gear and stop screw. See SUB-TP SENSOR ADJUSTMENT table.
- Connect ohmmeter between terminals IDL2 and E2 of sub-TP sensor connector. See Figure. Rotate sub-TP sensor counterclockwise until there is no continuity, then rotate it clockwise until there is continuity. Tighten sub-TP sensor mounting screws. Inspect sub-TP sensor again.
| Application | Feeler Gauge Thickness |
|---|---|
| GS300 | .016" (.41 mm) |
engine. Ensure idle speed is 650-750 RPM. While fully extending dashpot rod with a screwdriver, check engine speed. If engine speed (dashpot set speed) is not within specification, rotate dashpot adjusting screw as necessary. See DASHPOT SET SPEED SPECIFICATIONS table.
| Application | Dashpot Set RPM |
|---|---|
| GS300 | 1400-2200 |
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.