Throttle Position Sensor: Replacement, Costs & DIY

How to get transparent, long-lasting repairs

If you want to fix the root cause, relying on online price estimates is misleading. Online estimates will only price the specific repair, e.g., the throttle position sensor replacement, and they won’t consider whether your vehicle needs an inspection to investigate and deal with the problem as a whole.

The solution for the root cause of your throttle position sensor being damaged is based specifically on your vehicle’s condition. This involves many components and procedures that won’t appear on online estimates because every case has specific needs.

The best way to get a precise estimate is to seek shops with a “transparency process” to perform an ignition system inspection for you. Their transparency relies on documenting everything about your throttle position sensor’s condition and clarifying their findings using edited images and videos they took of your car, explaining their suggestions and quotes.

Let’s see an example of an ignition system investigation because of a faulty throttle position sensor.

A Transparent, Long-lasting Throttle Position Sensor Repair Example

A complete engine fuel-injection system inspection checks everything about the system’s condition, investigates chronic issues, and checks if all combustion and ignition components (fuel lines, fuel injectors, valves, spark plugs, etc.) work as expected.

For instance, if a shop is requested to do an engine system inspection due to a faulty throttle position sensor, the mechanics will look through each sensor-related component.

They’ll check every component for signs of wear, tear, or leaks to find if it is damaging or stressing the throttle position sensor. The inspection may reveal that various components need replacement and identify a culprit causing extra stress on the throttle position sensor.

What exactly is a throttle position sensor (TPS)?

A Throttle Position Sensor (TPS) is a crucial component in a vehicle’s fuel management system. It monitors the position of the throttle valve and sends that information to the engine control unit (ECU). The ECU then uses this data to adjust the air-fuel mixture and ignition timing, optimizing engine performance, fuel efficiency, and emissions.

How to test the throttle position sensor?

There are three main ways to test it: using a multimeter, a scan tool, or an oscilloscope. Here’s how you can do it yourself with a multimeter, which is the most common method.

1. Tools You’ll Need:

 Digital multimeter (DMM)
Basic hand tools (if removal is needed)
Vehicle repair manual (for reference)

2. Locate the TPS

• The TPS is mounted on the throttle body and connected to the throttle plate.

• It usually has three wires:

• Reference voltage (VCC) – 5V (from ECU)

• Signal wire – variable voltage output (to ECU)

• Ground – 0V

3. Testing the TPS with a Multimeter

A. Checking for Power (5V Reference)

1. Turn the ignition ON, but do not start the engine.

2. Set your multimeter to DC voltage (20V range).

3. Probe the reference voltage wire (typically the middle or first wire).

4. The reading should be around 5V.

• If no voltage, check for wiring issues or a bad ECU.

B. Checking the Ground Wire

1. Keep the multimeter on DC voltage mode.

2. Place the black probe on the TPS ground wire.

3. Place the red probe on the battery’s positive terminal.

4. You should get 12V or higher.

• If you get 0V, there’s a bad ground connection.

C. Checking TPS Signal Output

1. Keep the ignition ON (engine off).

2. Connect the black probe to the ground wire and the red probe to the signal wire.

3. Slowly press the accelerator pedal (or manually open the throttle).

4. The voltage should increase smoothly from 0.5V (closed throttle) to 4.5V-5V (wide open throttle, WOT).

• If the voltage jumps, drops, or has dead spots, the TPS is faulty.

4. Alternative Testing Methods

A. Using a Scan Tool

• Plug in an OBD2 scanner and go to live data.

• Look for Throttle Position (% or voltage).

• Press the throttle gradually and check if the value changes smoothly.

B. Using an Oscilloscope

• This gives a real-time graph of TPS voltage.

• Any sudden spikes or dips in the signal mean the TPS is bad.

Where is the Throttle position sensor located?

The Throttle Position Sensor (TPS) is located on the throttle body, which is typically mounted between the intake manifold and the air intake hose. It is directly connected to the throttle plate (butterfly valve) and detects its position as you press the accelerator pedal.

Is replacing the TPS yourself a good idea?

Replacing the Throttle Position Sensor (TPS) yourself can be a good idea if you’re comfortable working on your car. It’s usually a straightforward job, especially on older vehicles where the TPS is mounted externally. However, on some modern cars, the TPS is built into the throttle body, making it harder or even impossible to replace separately.

The 'Find Shops Providing a DVI' Method

A shop with transparent inspections commonly does DVIs too, which are free-of-charge visual inspections with the same level of transparency. You can find shops providing a DVI to get the reassurance that any inspection or repair will also be transparent.

This method focuses on two things:

• Does the shop have a modern DVI?

• Does the shop have certifications?

What’s a DVI? As mentioned earlier, it’s like an annual physical visit to the doctor to assess the body’s vital signs, but for a car instead; most auto repair shops don’t charge to do it.  The DVI regularly creates your vehicle’s “state of health,” explaining its overall condition. 

The mechanic uses the DVI results to inform the conditions of your vehicle’s systems and the recommendations to get it running reliably. If they find issues, they’ll list them in order of priority.