In this article, we will discuss the common problems that can cause Kia and Hyundai vehicles to not accelerate. In one situation, a Kia was only accelerating to about 15 mph and would not go any faster.

Problem

kia won't accelerate

Kia or Hyundai vehicles may fail to accelerate due to problems with the throttle position switch. When the driver presses the gas pedal, the maximum speed that the car can reach is about 10 or 15 mph. Some symptoms include that the engine has no power when you press the gas pedal or that the RPMs will not go past 2000.

The first warning that you may get is the check engine light will come on. Soon after you may notice that the engine or vehicle speed does not increase when you press the gas pedal. It is common as well for this issue to be intermittent at the early stages.

It is easy to misdiagnose this problem as an engine misfire. Thus changing the spark plugs is not going to solve the problem if the issues are caused by a faulty throttle position sensor. You may also wonder if the car is out of gas. That's why it is important to read the CEL

Common Causes

 

Throttle Position Switch

Hyundai Kia Engine Has No Power / Very Weak

The most common issue that can your vehicle not to accelerate is a faulty throttle position switch, also referred to as the TPS. The Throttle Position Sensor is a potentiometer that controls the throttle valve. Check with the dealer to see if they have an updated position switch.

Replacing the TPS at the dealership can cost around $400-$600 USD depending on your location and model. Replacement TPS for Kia and Hyundai can also be purchased online. 

Catalytic Converter

CATALTYIC CONVERTER

A bad catalytic converter can also cause your Kia / Hyundai not to accelerate.

Typically you can get to speeds over 50mph when the catalytic converter is defective, but it may take a while for the car to get up to that speed.

When the catalytic converter gets clogged it creates excessive backpressure, and thus the vehicle loses power. You can have a muffler shop perform a backpressure exhaust test on your vehicle.

This will confirm if the catalytic converter is defective or not. Replacing cat converters can be expensive. They can cost close to $1,000 if you want an OEM catalytic converter but aftermarket units cost only $200-$300 USD at a muffler shop.

How to diagnose

Several fault codes may be present when the vehicle fails to accelerate. You can use an OBD2 scanner reader to retrieve the codes from your car.

Here is the list of codes that were triggered by a defective TPS.

Engine won't rev past 2000 RPM

  • P0123 - Throttle Position Sensor/Switch A Circuit High Input

Car Engine Hesitates when pressing gas pedal

  • P0222 - OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input

Engine shuts off when idling

  • P2101 - Throttle Actuator Control Motor Circuit Range/Performance

How to replace Throttle Position Sensor

Faulty Throttle Position Switch?

  1. Open the hood.
  2. Disconnect the negative battery terminal.
  3. Locate the electronic throttle body. The throttle body is mounted on the intake manifold assembly.
  4. Remove the air intake hose.
  5. Disconnect the electrical connector from the TPS.
  6. Remove the 4 bolts on the TPS using a 10 mm socket.
  7. Reinstall in reverse order. Tighten the bolts to 11.5 Nm.

 

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Thank you! 

Visitor
Member since 2020-07

Our 2012 Tuscon does some similar behavior: It would get to 20-30 mph and then the transmission would down shift, rev up, but loose drive power. No codes. Thought it was a clogged air filter, replaced that - no change. Thought it might be a problem with the torque converter, replaced transmission fluid - maybe slight improvement, but now the car mostly bogs down when attempting to accelerate instead of the downshifting with no accompanying increase in power to the wheels that was happening some before. Sometimes I can only get it over 30 going going down hill. If I manually downshift, I can get more RPMs and maybe a little more power, but it will still have a difficult time accelerating much. Maybe fuel starved, but then I wouldn't imagine that it would rev up to 4-5k RPMs. It did seem to behave slightly better after I filled the gas from 1/5 of a tank to full. At a bit of a loss for good ideas. Is it worh replacing the fuel pump?

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Visitor
Member since 2020-07

Our 2012 Tuscon does some similar behavior: It would get to 20-30 mph and then the transmission would down shift, rev up, but loose drive power. No codes. Thought it was a clogged air filter, replaced that - no change. Thought it might be a problem with the torque converter, replaced transmission fluid - maybe slight improvement, but now the car mostly bogs down when attempting to accelerate instead of the downshifting with no accompanying increase in power to the wheels that was happening some before. Sometimes I can only get it over 30 going going down hill. If I manually downshift, I can get more RPMs and maybe a little more power, but it will still have a difficult time accelerating much. Maybe fuel starved, but then I wouldn't imagine that it would rev up to 4-5k RPMs. It did seem to behave slightly better after I filled the gas from 1/5 of a tank to full. At a bit of a loss for good ideas. Is it worh replacing the fuel pump?

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Visitor
Member since 2020-07

I'd you get a answer with this problem, mine goes 15 miles than stops and engine sounds accelerated than comes back to coast for 2-5 miles p/h

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Visitor
Member since 2020-07

look at the crank shaft sensor

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Visitor
Member since 2020-07

Ok jennifer i have the solution for u my car i have changed three sensors last week i almost jailed a part shop dealer then i tried something....... I removed the air sensor as they mentioned that u should change it and covered it with aluminium foil paper with only the two bolts holes open and mounted it back to its place and the rev. Came back to normal and i still drive and no complains abt it...... My car is a hyundai getz 2009 model

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Visitor
Member since 2020-07

My car seems to be having this problem & I have taken my car to the Hyundai dealership over 4 times . They have kept it for weeks at a time but claim that they cant find amy problems with my car. My car is dangerous to drive. The dealership claims the problem doesn't happen when they drive the car but it happens to me EVERY time I'm driving the car !! this is very frustrating and upsetting.

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Visitor
Member since 2020-07

I have had this happen.... dies down and then seems to jump gears... Tranny is good... I just had new plugs and wires put on.. (140K miles) hit a code PO121 so I replaced the TPS after clearing the code.. Now it does it again..2 times since. but..no check engine light... no code. Now what I do is remove both cables off the battery and hold them together for 5 or 10 min. reattach and it works...for a few days... New plugs/wires and TPS....??????

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