Common Misdiagnoses of Throttle Position Sensor
Throttle position sensor symptoms are often mistaken for other issues. Recognizing these common misdiagnoses can potentially save you time and money.
1. Mass Airflow Sensor (MAF) Failure – The MAF sensor also measures air intake, and its symptoms can be similar to TPS issues. Both can cause poor acceleration and rough idling. However, MAF problems typically don’t cause the sudden acceleration changes associated with TPS failure.
2. Vacuum Leaks – A vacuum leak can cause erratic idling and poor performance, similar to TPS issues. However, vacuum leaks often produce a distinct hissing sound that TPS problems don’t.
3. Fuel Injector Problems – Clogged or bad fuel injectors can cause symptoms like rough idling and poor acceleration, which might be mistaken for TPS issues. However, fuel injector problems typically don’t cause the check engine light to come on as quickly as TPS issues do.
4. Ignition System Issues – Problems with spark plugs, ignition coils, or wires can cause misfires that might feel similar to the jerking associated with TPS failure. However, ignition issues usually produce more consistent symptoms across all driving conditions.
5. Catalytic Converter Blockage – A clogged catalytic converter can cause lack of power and poor fuel economy, similar to TPS issues. However, catalytic converter problems typically worsen gradually over time, while TPS issues often appear more suddenly.
How a Throttle Position Sensor Works
Every vehicle with an internal combustion engine has something called a throttle body, also referred to as a butterfly valve. This valve is positioned in the middle of the intake manifold and the air filter.
The job of the throttle is to manage the air flow that goes into the engine. As the driver steps on the gas pedal to accelerate the vehicle, more air is needed in the internal combustion chamber of the engine. While more air enters the engine, more fuel gets injected into it as well. The ignition of this mixture is how engine power is created. The position of the throttle determines how much air enters the engine.
When you want to accelerate the vehicle, the sensor gives the throttle position information to the engine control unit. From there, the engine control unit will manage the throttle and allow it to take in whatever amount of air is needed in the engine.
The harder you step on the gas pedal, the wider the throttle will open to allow more air flow into the engine. At the same time, more fuel will be injected into the engine cylinders to create a balanced mixture for combustion.