2003 Honda Civic SiFACTORY OEM SERVICE PROCEDURE

Throttle Body Test

NOTE:
  • Do not adjust the throttle stop screw. It is preset at the factory.
  • If the malfunction indicator lamp (MIL) has been reported on, check for diagnostic trouble codes (DTCs) (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. With the engine off, check the throttle cable movement. The cable should move without binding or sticking.
    • If the cable moves OK, go to step 2.
    • If the cable binds or sticks, check it and its routing.
    • If the cable is faulty, reroute it or replace it and adjust it (see THROTTLE CABLE ADJUSTMENT ), then go to step 2.
  2. Move the throttle lever by hand to see if the throttle valve and/or shaft are too loose or too tight.
    • If there is excessive play in the throttle valve shaft, or any binding in the throttle valve at the fully closed position, replace the throttle body.
    • If the throttle valve and shaft are OK, go to step 3.
  3. Connect the HDS or a scan tool to the DLC.
  4. Turn the ignition switch ON (II).
  5. Check the throttle position with the HDS or a scan tool. The reading should be about 10% when the throttle is fully closed and about 90% when the throttle is fully opened.
    • If the throttle position is correct, the throttle body is OK.
    • If the throttle position is not correct, replace the throttle body.
Factory Service Tools

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.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

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.