Intake Air System: Diagnosis Honda S2000 AP1

Throttle Body Test

Note. Do not adjust the throttle stop screw. It is preset at the factory.

Scheme 172

1. With the engine off, check the throttle cable operation. The cable should operate without binding or sticking. If the cable operates OK, go to step 2. If the cable binds or sticks, check it and its routing. If it's faulty, reroute it or replace it and adjust it (see «THROTTLE CABLE ADJUSTMENT»(ref-221333-S15624127062006022400000) ), then go to step 2.
2. Operate 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. Check for clearance (A) between the throttle stop screw (B) and the throttle lever (C) at the fully closed position. If there is any clearance, replace the throttle body (see «THROTTLE BODY REMOVAL/INSTALLATION»(ref-221333-S24874381242006022400000) ). Do not adjust the throttle stop screw.

Throttle Position Sensor Signal Inspection

Note. This procedure checks the APP sensor in its fully closed position. In any other position, the APP sensor stores DTCs which are covered in other troubleshooting procedures. Check for Temporary DTCs or DTCs with the HDS before doing this procedure. If any DTCs are indicated, troubleshoot them first, then do this procedure. Press the accelerator pedal several times to check its movement. If it does not move smoothly, check the pedal, the throttle cable, and the throttle linkage individually. If you find a problem in one of them, replace the part(s) that caused the problem.

Scheme 173

1. Connect the HDS or an OBD II scan tool to the data link connector (DLC) (A). On 2000-2001 models, the DLC is under the passenger's side of the dashboard. On 2002-2005 models, the DLC is behind the driver's side of the front console.
2. Turn the ignition switch ON (II).
3. Make sure the accelerator pedal is not pressed, then check the TP SENSOR in the DATA LIST with the HDS. If it is below 0.5 V, the throttle position sensor is OK. If it is above 0.5 V, adjust the throttle cable (see «THROTTLE CABLE ADJUSTMENT»(ref-221333-S15624127062006022400000) ), then go to step 4.
4. Make sure the accelerator pedal is not pressed, then check the TP SENSOR in the DATA LIST with the HDS. If it is below 0.5 V, the throttle position sensor is OK. If it is above 0.5 V, substitute a known-good ECM (see «HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES»(ref-221328-S04997151962006022400000) ), then go to step 5.
5. Make sure the accelerator pedal is not pressed, then check the TP SENSOR in the DATA LIST with the HDS. If it is below 0.5 V, the throttle position sensor is OK. If it is above 0.5 V, replace the throttle body (see «THROTTLE BODY REMOVAL/INSTALLATION»(ref-221333-S24874381242006022400000) ), then go to step 1 .