REPLACING THE THROTTLE BODY ASSEMBLY

Under some circumstances, it might be necessary to remove the throttle body

assembly. Sometimes it may be to thoroughly clean the inlet and throttle blade,

but more often it will be to replace it. The procedure is pretty straightforward.

Q: How to tell if you need a new throttle body?

A: If you find that your car idles quicker than usual, that may mean that the throttle body is sticking open. If your check engine light comes on and you find that you can’t get the car to accelerate above a certain rpm, the ECU has put you in limp mode. This means that there is something wrong with the drive-by-wire system. The most dangerous indicator is if the throttle sticks while driving and you can’t get the car to stop accelerating. If that ever happens, put the car in neutral and turn the key back one click and coast to the side of the road.

REMOVAL

1. Disconnect the ground cable from battery.

2. Lift up the vehicle. Remove the under cover.

3. Remove the clip (A), and loosen the clamps (B) and (C) securing the air intake boot.

4. Remove the air intake boot from the air cleaner case (rear) and throttle body, and move the air intake boot aside so that it does not interfere with the work.

5. Disconnect the connectors (A) from the throttle position sensor.

6. Disconnect the preheater hose (B) from the throttle body.

7. Remove the throttle body from the intake manifold.

INSTALLATION

Install in the reverse order of removal.

NOTE:

Before installing the new assembly, inspect the intake-manifold-to-throttle-body gasket for damage.  If it is damaged, it must be replaced.

If it is in good condition, it can be reused.

WARNING:

DO NOT place fingers in or around the throttle body plate. If the throttle body is energized, the throttle plate could move causing personal injury. Always disconnect the negative battery cable prior to servicing the throttle body.

CAUTION:

DO NOT move the throttle plate while power is connected to the throttle body. This may cause fault codes to set.

Q: Is there anything that has to be done after installing the replacement throttle body?

A: A relearn calibration procedure is necessary after installation of replacement throttle body

Q: What is throttle body relearn?

A: Idle Relearn (aka throttle body relearn) is the procedure that is required to obtain the correct idle speed after replacing electronic throttle body, disconnecting a battery cable, clearing a check engine light, etc.

Relearn A MECHANICALLY CONTROLLED THROTTLE BODY

1. Remove terminals from the battery for 15 minutes.

2. Start the engine. Let it idle for 10 minutes. Remember not to switch on any additional consumers.

3. Stop the engine for about 10 seconds. Start it again.

4. Wait until the power unit warms up to the operating temperature. After that, you can start using the vehicle.

Take notice: you might need to drive 150–200 km until the idling stabilises.

Relearn AN ELECTRONICALLY CONTROLLED THROTTLE BODY

The readjustment process might vary in different vehicles. Therefore, before you start the procedure, consult the vehicle manual for the exact step sequence.

The general algorithm is as follows:

1. Study procedure and try to remember it. You’ll have to act quickly so you won’t have time to check the details.

2. Start the engine. Warm it up to the working temperature.Stop it for 10 seconds.

3. Switch on the ignition for 3 seconds.

4. Press the accelerator pedal quickly for 5 times. One depression should take one second.

5. Press the gas pedal to the floor for 7 seconds. Keep it depressed until the “Check Engine” light burns steady and hold it for 3 more seconds.

6. Press the gas pedal to the floor for 7 seconds. Keep it depressed until the “Check Engine” light burns steady and hold it for 3 more seconds.

7. Release the gas pedal and start the engine.

Q: HOW TO PREVENT THE THROTTLE BODY FROM GETTING DIRTY?

A: 1. Use only high-quality fuel. Otherwise, impurities and contaminants will get inside the engine causing the rapid formation of carbon deposits on the throttle body. For the same reason, you shouldn’t neglect the fuel filter replacement. It is recommended to flush the fuel tank from time to time.

2. Replace the air filter on time. Always make sure that the intake system is air-tight. This simple check prevents unfiltered air from being sucked into the intake system in places where its components are not connected tightly.

3. Always make sure that the crankcase ventilation system is fault-free. Its malfunctions cause a fast formation of oily deposits on elements of the throttle body.

Fits the Following Vehicles:

Lexus ES330 3.3L 2004-2005
Lexus RX330 3.3L 2004-2006
Lexus RX400h 3.3L 2006-2008
Toyota Camry 3.0L 2002-2006
Toyota Highlander 3.3L 2004-2009