The mechanic will replace the throttle body on your car if:
It can’t be cleaned properly.
The throttle flap, throttle shaft, or the mechanical linkages to the throttle cable are damaged.
The electronic throttle actuator is faulty.
There is a damaged throttle body or TP sensor electrical connector.
Additionally, it’d be a good idea to get your cars throttle and fuel delivery system inspected for:
A faulty throttle position sensor
Gas pedal sensor problems
Intake manifold pressure sensor issues
A clogged air filter
A bad Mass Airflow sensor (MAF sensor)
A failing fuel pump
A malfunctioning fuel injector
A defective fuel pressure regulator
These parts can cause problems similar to bad throttle body symptoms.
You will need: screwdrivers, socket set, spanners, needle pointed pliers.
Throttle Body Replacement
1. Refer to the service manual for identification and location of the throttle body.
2. Remove the air intake duct from the throttle body once it is located.
3. Check the throttle body as well as the assembly and ports. If there is wearing in the assembly it may also require replacement.
4. Pull out the cables from the throttle body.
5. Remove the hoses such as air or vacuum hoses from the throttle body.
6. Disconnect the throttle position sensor.
7. Remove the screws that are holding the throttle body in the assembly.
8. Remove the throttle body carefully after disconnecting everything.
9. Properly clean the assembly and port to remove any carbon build up.
10. Compare the old throttle body with the new one.
11. Install the throttle body in the port.
12. Fasten the bolts and screws to hold it in place.
13. Connect all the things that you previously removed.
14. After connecting everything start your engine and test for the new throttle body.
15. Perform the following check as a final test. Start the engine and take the car for a test drive. On your return, let the engine idle for about two minutes and listen for problems in the idle, ensuring that it is smooth. If it is not, then there may be additional problems throughout your engine.
Q: What is throttle body relearn?
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. The symptoms are, idle is too low, too high, or erratic. Sometimes the engine stalls when you stop at the traffic light. And you may see the check engine light come on with the idle speed related trouble codes.
Q: Why does Idle Relearn need?
Many newer vehicles use an electronic throttle body which contains a throttle plate, motor, and sensors. They are responsible for regulating all air flow into the engine, including the air flow for maintaining idle speed. When idling, the vehicles computer sends a signal to the throttle body and controls the throttle plate to adjust the idle speed depending on the engine temperature and whether AC is on or off. When the computer loses the connection to the throttle body, it loses the position of the throttle plate. Thus, the vehicle computer needs to relearn the throttle plate after losing connection to it.
Q: When is Idle Relearn required?
As mentioned above, Idle Relearn is required when the vehicle computer loses the connection to a throttle body. And, many things cause it to happen.
Disconnecting a battery cable
A battery dies
Replacing a battery
Clearing the check engine light
Replace an electronic throttle body
Cleaning an electronic throttle body in an inappropriate way
etc…
Note: Please note that it doesn’t mean that you will need the idle relearn after these repairs or incidents. It totally depends on models of vehicles.
Q: Does my car need Idle Relearn?
In general, the procedure of idle relearn is necessary on vehicles with electronic throttle body (=ETB aka DBW Drive-By-Wire).
If you are experiencing a rough idle on your vehicle after you disconnect a battery for any reasons, you need to perform the idle relearn procedure.
Q: How can you get the procedure of idle relearn?
Unfortunately, not all repair manuals have the information about idle relearn. And you may or may not find it in the owner’s manuals. So where can you find it? Go online, search “idle relearn + make, model, and year of your vehicle,” and you may get results. If not, search “idle relearn + make” only. The procedure may be the same among all vehicles from the same manufacturer.