2017 Toyota Yaris IA Has Rough Idle

Common Causes of Rough Idling in Your 2017 Toyota Yaris iA and How to Resolve Them

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
21% chance it's the
Spark Plugs
0%
15% chance it's the
Ignition Coil
0%
64% chance it's
Something else
The most common reasons a 2017 Toyota Yaris iA has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
  • Spark Plugs: Worn or fouled spark plugs can lead to misfires, poor fuel economy, and difficulty starting the engine.
  • Ignition Coil: A faulty ignition coil can cause misfires, rough idling, and difficulty starting the engine due to inadequate spark delivery to the spark plugs.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2017 Toyota Yaris iA has rough idle?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Here are a few common symptoms of worn-out brake pads:

  1. Low brake pad warning light is on: Not all vehicles are equipped with this system, but if yours is, this dashboard indicator light will likely be the first signal it’s time to replace your brake pads.
  2. Brakes start to squeal regularly: This is often one of the first signs of worn brake pads and is caused by a metallic piece built into brake pads for this exact purpose. This part contacts the brake rotor to make a squealing or whining noise when the pads are low.
  3. Brakes make loud grinding noise: If not addressed early enough, your brake pads may get so worn that the metal backing plate of the pad grinds against the metal rotor.
  4. Brake pads look thin: You may be able to visually check your brake pad thickness to determine if they need replacement.

Customers with drum brake systems often specify they have lost braking power, or that the vehicle's brakes are making noise. This is because brake drums do not dissipate heat very well, so the heat from hard braking will cause stress fractures. These fractures make can make noise on the brake shoes as the drum revolves around the shoes. Lastly, the brake shoes may not be problematic, but may cause a grinding noise while stopping. This would indicate the shoes have no braking material left, and the brake shoes must be changed before the vehicle can be safely driven.

Learn more about brake shoe symptoms

Most often, a brake system inspection will just be a routine portion of manufacturer specified maintenance, and will be performed at mileage intervals. In those cases, there will likely be no symptoms. However, when a brake system makes a funny noise, causes vibration, is hard to use, will not slow the vehicle, prevents the vehicle from driving, makes the vehicle pull to one side, or leaks brake fluid, the vehicle will need a visit dedicated to the inspection of the brake system.

What are the initial diagnostic steps to take for a rough idle in a 2017 Toyota Yaris iA?

When faced with a rough idle in your 2017 Toyota Yaris iA, it's essential to adopt a systematic diagnostic approach to identify the root cause effectively. Start by checking for error codes using an OBD-II scanner, as these codes can reveal specific issues within the engine's systems. Next, inspect the spark plugs for wear or fouling, as these components play a crucial role in engine performance. A dirty air filter can also hinder airflow, so ensure it is clean and replace it if necessary. Additionally, examine the vacuum hoses for leaks, which can disrupt the air-fuel mixture and lead to rough idling. Don't overlook the fuel system; check the fuel filter and injectors for any blockages or malfunctions. Finally, inspect the throttle body for any carbon buildup that could affect its operation, and consider cleaning it to enhance idle quality. By following these steps, you can effectively diagnose and address the rough idle issue in your Yaris iA, potentially saving time and money on repairs.

What are the common problems that could cause a rough idle in a 2017 Toyota Yaris iA?

When diagnosing a rough idle in a 2017 Toyota Yaris iA, it's essential to consider several common problems that could be affecting the vehicle's performance. One of the primary culprits is a dirty or clogged air filter, which can significantly restrict airflow to the engine, leading to an uneven idle. Additionally, faulty spark plugs are notorious for causing misfires; if they are worn out, they can disrupt the combustion process and result in a rough idle. Another potential issue is vacuum leaks, which can disturb the air-fuel mixture necessary for smooth engine operation. Problems within the fuel system, such as a clogged fuel filter or a malfunctioning fuel pump, can also impact engine performance and contribute to rough idling. Furthermore, a malfunctioning mass airflow sensor can lead to incorrect air-fuel mixture readings, exacerbating the idle issue. Lastly, issues with the Exhaust Gas Recirculation (EGR) valve can interfere with the combustion process, causing the engine to idle roughly. By addressing these common problems through regular maintenance and timely repairs, you can help ensure a smoother idle and overall better performance for your Yaris iA.

How urgent is it to address the rough idle in my 2017 Toyota Yaris iA?

Addressing a rough idle in your 2017 Toyota Yaris iA is not just a matter of comfort; it is crucial for the overall health and performance of your vehicle. A rough idle can indicate serious underlying problems such as faulty spark plugs, vacuum leaks, or issues within the fuel system. If these symptoms are ignored, they can lead to more severe complications, including engine misfires, decreased fuel efficiency, and even significant engine damage over time. The urgency of resolving a rough idle cannot be overstated, as neglecting it may result in costly repairs and a decline in your vehicle's reliability. Regular maintenance and prompt attention to these symptoms are essential to prevent further damage and ensure the longevity of your Yaris iA. Therefore, if you notice a rough idle, it is advisable to take action quickly, whether through DIY diagnostics or consulting a qualified mechanic, to safeguard your vehicle's performance and safety.

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