2012 Lexus LS600h Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2012 Lexus LS600h and Solutions for a Smoother Ride

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Reviewed by
Devin Cabugcal
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 2012 Lexus LS600h 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 2012 Lexus LS600h 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.

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 2012 Lexus LS600h?

When faced with a rough idle in your 2012 Lexus LS600h, it's essential to adopt a systematic diagnostic approach to effectively identify and resolve the problem. Start by checking if the check engine light is illuminated; if so, using an OBD-II scanner to retrieve error codes can provide valuable insights into potential issues. Next, inspect the spark plugs for wear or fouling, as these can significantly impact engine performance. A thorough examination of the air filter is also crucial, as a clogged filter can restrict airflow and contribute to a rough idle. Additionally, inspect vacuum hoses for any signs of damage or disconnection, as leaks can disrupt engine operation. Cleaning the throttle body can enhance airflow and improve idle quality, while checking the fuel system for clogs or pump failures is vital for maintaining optimal engine performance. Don't overlook the idle air control valve and mass airflow sensor, as both play critical roles in regulating airflow and fuel mixture. By following these steps, you can effectively diagnose and address the rough idle issue, ensuring your Lexus runs smoothly.

What are the common causes of a rough idle in a 2012 Lexus LS600h?

When dealing with a rough idle in your 2012 Lexus LS600h, it's crucial to understand the common problems that may be at play. One of the primary culprits could be dirty or clogged air filters, which restrict airflow to the engine and disrupt its performance. Additionally, faulty spark plugs or ignition coils can lead to misfiring, causing the engine to run unevenly. The fuel system is another area to investigate; a clogged fuel filter or a malfunctioning fuel pump can significantly impact engine performance and contribute to rough idling. Furthermore, vacuum leaks in the intake system can alter the air-fuel mixture, exacerbating the issue. Lastly, problems with the EGR (Exhaust Gas Recirculation) system can also affect engine performance and lead to a rough idle. By addressing these potential causes, you can help ensure your Lexus LS600h runs smoothly and efficiently.

How urgent is it to address the rough idle in a 2012 Lexus LS600h?

Addressing a rough idle in your 2012 Lexus LS600h should be treated as a priority due to the potential risks associated with ignoring this symptom. A rough idle can indicate underlying engine problems that, if left unresolved, may escalate into more severe issues, leading to costly repairs and decreased vehicle performance. Additionally, neglecting this issue can result in reduced fuel efficiency, which not only impacts your wallet but also contributes to increased emissions. More critically, a rough idle could signal serious malfunctions, such as faulty sensors or clogged fuel injectors, which can compromise the safety and reliability of your vehicle. By taking prompt action to diagnose and repair the rough idle, you not only enhance the longevity of your Lexus but also ensure a smoother and safer driving experience. Therefore, if you notice this symptom, it is advisable to investigate and address it as soon as possible to avoid further complications down the line.

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2012 Lexus LS600h Rough Idle: Causes & Repair Costs