Throttle body — check, replacement and initialization
Check
1. Turn the ignition on.
2. While listening near the throttle body, press and release the accelerator pedal. The throttle body motor should make noise, indicating operation. If excessive noise is heard, inspect the throttle body and replace as necessary.
3. Connect a scan tool and monitor the throttle sensor position.
4. Press the accelerator pedal to the floor and hold. The throttle sensor position values should be 60 percent or greater. If the value is less than 60 percent, inspect the throttle body and replace if necessary.
5. Turn the ignition off and disconnect the throttle body connector.
6. Using a digital volt-ohm meter (DVOM), measure resistance between pins 1 and 2 of
the throttle body connector. Resistance should be 0.3 ohms to 100 ohms.
Replacement
Warning: Wait until the engine is completely cool before beginning this procedure.
7. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
8. Remove the engine cover.
9. Remove the intake duct and air filter cover.
10. Remove the air filter housing with the MAF sensor and bracket (see Air filter housing — removal and installation).
11. Clamp off the coolant hoses to the throttle body to minimize coolant loss. Remove the clamps and disconnect the two coolant hoses at the throttle body (see illustration). Plug the coolant hoses to prevent coolant leakage.
12. Remove the bolt for the fuel hose bracket (see illustration).
i. 12 Disconnect the coolant hoses (A) and the fuel hose bracket (B)
13. Disconnect the electrical connector from the throttle body (see illustration).
14. Remove the throttle body mounting bolts (see illustration) and remove the throttle body.
i. 14 Disconnect the throttle body electrical connector (C) and remove the throttle body bolts (D)
15. Remove and discard the old throttle body gasket.
16. Installation is the reverse of removal. Be sure to use a new gasket and tighten the throttle body mounting bolts to the torque listed in this Chapter’s Specifications. Check the coolant level, adding as necessary (see Tune-up and routine maintenance).
Idle initialization
Note: After cleaning the throttle body, perform the following procedure. After removing and installing or replacing a throttle body, perform the following procedure. After replacing the ECM, perform the following procedure.
17. Ensure the battery is connected and the ignition is Off.
18. Remove the EFI No. 1 fuse and ETCS fuses from the under-hood junction box. Wait a minimum of 60 seconds after removing the fuses.
19. Install the fuses after waiting a minimum of 60 seconds after removing the fuses.
20. Turn the ignition switch to on (DO NOT start the engine) without depressing the accelerator pedal.
21. Using a scan tool, clear any DTCs that are set.
22. Start the engine and bring to operating temperature. Monitor idle speed at operating temperature. With AC and all accessories Off, idle speed should be 720 RPM to 820 RPM.
23. Using the scan tool, monitor the throttle sensor position.
24. Press the accelerator pedal to the floor and hold. The throttle sensor position values should be 60 percent or greater.
25. Road test the vehicle and verify proper operation.