Idle Air Control Motor Procedures for a 1999 Tacoma

The Toyota Tacoma featured three engines in 1999: The 2.4-liter 2RZ-FE engine, the 2.7-liter 3RZ-FE engine and the 3.4-liter 5VZ-FE engine. The process for removing the idle air control motor is the same for all three, but the process for removing the throttle body is a bit different on the 3.4-liter engine. Essentially, the idle air motor controls idle speed by directing a constantly metered amount of air around the closed throttle plate as necessary to maintain a constant rpm.

Instructions

Removal

1

Slide the drain pan under the radiator petcock. Open the petcock with your fingers or pliers. Open the radiator cap so the coolant will drain faster. If the coolant is less than 2 years old and the coolant and container are clean, you can reuse the coolant.

2

Remove the throttle body as outlined in the sections titled "Throttle Body Removal 2RZ-FE and 3RZ-FE Engines" or "Throttle Body Removal 5VZ-FE Engines", depending on the engine. Check the engine designation on the sticker on the underside of the hood.

3

Remove the screws that hold the idle air control valve onto the throttle body using a torx-bit and ratchet. Discard the O-ring or gasket.

Instalation

4

Clean the gasket-mounting surface with a shop rag. Fit the gasket in its groove in the throttle body.

5

Mount the idle air control valve onto the throttle body. Tighten the screws snugly with the torx-bit and ratchet. Install the throttle body pursuant to the instructions for your particular vehicle in the "Throttle Body Installation 2RZ-FE and 3RZ-FE Engines" or "Throttle Body Installation 5VZ-FE Engines."

6

Close the petcock on the radiator. Fill the radiator with the old coolant if it is clean and less than 2 years old. If the coolant is contaminated or old, fill the radiator with 50-50 mixture of ethylene-glycol antifreeze/coolant and water. You can purchase premixed 50-50 antifreeze in any auto parts store.

7

Start the engine and allow it to come to operating temperature. Do not install the radiator cap yet. The coolant will not pass the thermostat when the engine is cold. As the engine warms to normal operating temperature the thermostat will open. At this point the coolant level will drop. Top off the antifreeze as needed with the 50-50 mixture. Reinstall the radiator cap.

Throttle Body Removal 2RZ-FE and 3RZ-FE Engines

8

Disconnect the accelerator cable from the throttle body if your Tacoma has a manual transmission. Disconnect the accelerator cable and the throttle cables from the throttle body if your Tacoma has an automatic transmission. Rotate the throttle linkage to wide-open throttle and the cables can be rotated up and slipped out of the linkage.

9

Remove the air cleaner hose and resonator using a flat-head screwdriver. Mark the air hose from the IAC valve and the vacuum line from the fuel pressure regulator with the masking tape and white marker for ease of installation. Remove both lines. Remove the engine wiring harness clamp. Remove the two bolts and hose clamp on the intake air intake connector, then remove the connector from the engine.

10

Disconnect the PCV hose. Mark the EVAP hose, the three vacuum hoses and the hose for the power steering idle-up with the tape and a white marker. Disconnect the hoses.

11

Unplug the throttle position sensor and the IAC valve connectors with your fingers or with the help of a flat-head screwdriver. Remove the two retaining bolts and two retaining nuts on the throttle body, using a wrench. Lift the throttle body out of the engine compartment. Discard the gasket.

Throttle Body Installation 2RZ-FE and 3RZ-FE Engines

12

Clean the cast aluminum parts of the throttle body with the soft brush and carburetor cleaner. Clean the passages and opening with the compressed air.

13

Install the new gasket onto the throttle body. Install the throttle body and torque the nuts and bolts to 14 foot-pounds. Reinstall the vacuum lines. Plug in the throttle position sensor and IAC valve connectors.

14

Reinstall the throttle and accelerator cables. Install the hoses. Reconnect the PCV hose and the air cleaner hoses.

Throttle Body Removal 5VZ-FE Engines

15

Remove the cruise control actuator cable and the accelerator cable from the throttle body by rotating the linkage to wide-open throttle. Rotate the cables up and slide them out of the linkage. If your Tacoma has an automatic transmission, disconnect the throttle valve cable from the throttle body.

16

Remove the air cleaner hose using the flat-head screwdriver. Unplug the throttle position sensor and IAC valve connectors with your fingers or the flat-head screwdriver. Mark the water and vacuum hoses attached to the throttle body with the tape and white marker. Disconnect the hoses.

17

Disconnect the ignition coil wiring. Unbolt the throttle body and discard the gasket.

Throttle Body Installation 5VZ-FE Engines

18

Clean the cast aluminum parts with the soft brush and carburetor cleaner. Clean the passages and the opening with compressed air.

19

Install the new gasket onto the throttle body with the tab upwards. Install the throttle body and torque the retaining bolts to 13 foot-pounds. Reconnect the ignition coil wiring. Reconnect the water and vacuum hoses.

20

Plug in the throttle position sensor and IAC valve connectors. Reinstall the throttle control cables onto the throttle body. Reconnect the PCV and air cleaner hoses.