How to Replace the IAC Valve on a 4.6L/5.4L F-150

How to Replace the PCV Valve on a 4.6L/5.4L F-150

F-150 Fuel Filter Replacement

F-150 Serpentine Belt Replacement

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Return to F150 Maintenance & Repair section.

 

F-150 TPS Replacement

How to Replace the TPS on the 4.6L and 5.4L V-8

 

The throttle position sensor, or TPS, is a potentiometer that sends a signal to the engine's control module. The voltage of the signal sent to the control module varies with the position of the throttle. While the control module automatically adjusts the TPS signal to compensate for normal sensor wear, over time the unit can produce a poor or incorrect signal. Assuming the TPS is faulty, replacement can rejuvanate performance and throttle response.

 

Click any image to view fullize.

On the 4.6L and 5.4L V8, the throttle position sensor (TPS) is located on the driver's side of the throttle body and is attached by 2 phillips head bolts. Remove the plastic engine cover to access the throttle body, then locate the TPS. You may be required to remove the hose that connects to the IAC valve as well as the metal bracket that mounts the plastic engine cover. You will want good access to the TPS to ensure you do not strip the screws.

Disconnect the wiring harness that plugs into the TPS by pressing the locking tab and then pulling towards the front of the truck. Using a phillips head driver or socket, remove the old TPS. The screws are tight because they are applied with thread locker during assembly. Be extremely careful not to strip the heads of the screws, as this will be a time consuming repair. Here, a 1/4 drive socket, 4 inch extension, and phillips head driver were used to get the proper leverage to remove it without stripping.

Once removed, the TPS will pull right off the throttle body. Make a note of the tang that rotates to actuate the TPS, as you'll need to pay attention to this during installation of the new throttle position sensor.

To install the new TPS, position the front of the TPS at an approximately 45 degree angle downwards with the harness plug facing you, insert it into position (you need to anlign the tang with the groove in the TPS), then twist back up until the bolt holes line up. Reinstall the bolts, using a small dab of thread locker on each to ensure they will not vibrate loose over time.

With the throttle position sensor reinstalled, reattach the wiring harness, IAC hose, engine cover bracket, and engine cover.

Not being particularly fond of the phillips head bolts that attach the TPS to the throttle body, as the heads can strip easily, the factory hardware was replaced by fasteners with an allen head instead. These were acquired for around 20 cents each at the local hardware store, and will be much easier to remove should the TPS require replacement again. It is highly recommended that you consider installing new hardware, especially if your phillips screwdriver slipped and marred the bolt heads during removal.