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A Guide to the 2001-2013 Kia Optima Neutral Safety Switch

If your Optima won't start or is shifting strangely, the neutral safety switch could be the problem.

3 minutes to read 2001-2013 Kia Optima
Difficulty
2/5
Est. Time
1 hrs
DIY Doable?
✅ Yes
Shop Labor
$95-$150
⚠️ Drivable, but... — You can drive, but if the car starts in any gear or fails to start intermittently, you risk being stranded or causing an accident.
Key Takeaways
  • A no-start condition or starting in only Park or Neutral are key symptoms of failure.
  • A P0705 trouble code almost always points to a bad neutral safety switch.
  • Quality aftermarket brands like Standard, Beck Arnley, and Rostra are reliable, cost-effective alternatives to OEM.
  • Replacement is a manageable DIY task for those with basic tools, located on top of the transmission.
Your Kia Optima has a part called the neutral safety switch. It is also known as an inhibitor switch or transmission range sensor. This switch does two important jobs. First, it is a safety device that only allows the engine to start when the transmission is in Park or Neutral. This prevents the car from lurching forward or backward when you start it. Second, it tells the car's computer which gear you have selected and turns on your reverse lights when you shift into Reverse.

Is Your Kia Optima Neutral Safety Switch Failing?

When the neutral safety switch on a 2001-2013 Optima starts to go bad, it can cause several frustrating problems. The most common issue is trouble starting the car. You might find it only starts in Neutral but not in Park, or the other way around. In more serious cases, the car won't start at all, even though the dashboard lights and radio turn on. Another dangerous symptom is the ability to start the engine in any gear, which can cause the car to move unexpectedly. You may also notice that your backup lights don't work anymore or that the transmission shifts harshly.

🎬 Watch: Learn more about common symptoms of a failing switch.

Check Engine Light and Codes

A failing neutral safety switch will often trigger the Check Engine Light. If you scan the car's computer, you will likely find the trouble code P0705, which points to a malfunction in the transmission range sensor circuit. 🎬 See how to test and replace a switch with code P0705. This is a strong indicator that the switch needs to be replaced.

Choosing the Right Aftermarket Switch for Your Optima

When replacing the neutral safety switch, you don't have to buy the original part from a Kia dealer. Aftermarket parts can offer similar quality, often at a better price. For the 2001-2013 Optima, brands like Standard Ignition, Beck Arnley, and Rostra Powertrain are common choices.

  • Standard Ignition (Standard Motor Products): This is a well-known brand that produces a wide range of automotive parts. Their switches are designed to be direct-fit replacements that match original equipment (OE) specifications for function and reliability. They are a solid, dependable choice for most repairs.
  • Beck Arnley: This brand specializes in parts for foreign nameplate vehicles like Kia. They focus on matching the original part's form, fit, and function by working with a global network of manufacturers. Forum users often consider their parts to be near-OE quality, making them a trusted option.
  • Rostra Powertrain: Rostra is a manufacturer that produces electronics for both original equipment and the aftermarket. This means they have experience building parts to carmaker standards. Their products are engineered to meet or exceed OE performance and are known for durability.

OEM vs. Aftermarket Quality

For a part like the neutral safety switch, a quality aftermarket brand is a reliable and cost-effective alternative to the OEM part. There are no widespread reports of premature failure with reputable aftermarket switches on the Optima. Since the job is relatively simple, the cost savings of using an aftermarket part make sense for many owners.

Cost to Replace a Kia Optima Neutral Safety Switch

The total cost depends on whether you do the work yourself or hire a mechanic. The part itself is affordable, but labor will add to the final price.

Part or Service Estimated Cost
New Aftermarket Part $74 - $76
New OEM Part $50 - $90
Shop Labor $95 - $150
Total Professional Replacement $170 - $226

Frequently Asked Questions

Can I replace the neutral safety switch myself?

Yes, this is a DIY-friendly job for someone with basic tools and mechanical skill. The switch is located on top of the transmission and is accessible after removing the air filter housing. You will need to disconnect the battery, unplug the old switch, remove the shift cable and lever, and then unbolt the switch. The new switch must be aligned correctly during installation.

🎬 Watch this DIY tutorial to fix your transmission range sensor.
Are there any recalls for the 2001-2013 Optima neutral safety switch?

No, there are no specific recalls for the neutral safety switch on the 2001-2013 Kia Optima. While Kia has issued a service action (SA317A) for this switch on some newer 2017 models, it does not apply to this generation.

What is the difference between a neutral safety switch and an inhibitor switch?

There is no difference. They are different names for the same part. It may also be called a transmission range sensor.

Will a bad neutral safety switch leave me stranded?

It can. If the switch fails completely, it can prevent the engine from starting at all, which could leave you stranded. If you notice intermittent starting problems, it's best to get the switch replaced soon to avoid this.

Symptoms of a Bad Neutral SAFETY SWITCH (With Proven Fixes)
Symptoms of a Bad Neutral SAFETY SWITCH (With Proven Fixes)
4 SYMPTOMS OF A BAD NEUTRAL SAFETY SWITCH
4 SYMPTOMS OF A BAD NEUTRAL SAFETY SWITCH
SYMPTOMS OF A BAD NEUTRAL SAFETY SWITCH
SYMPTOMS OF A BAD NEUTRAL SAFETY SWITCH
How To Test and Replace the Neutral Safety Swtich / Inhibitor Switch P0705
How To Test and Replace the Neutral Safety Swtich / Inhibitor Switch P0705
How to FIX Your Transmission Range Sensor (DIY Tutorial)
How to FIX Your Transmission Range Sensor (DIY Tutorial)

Technical Specifications

OEM Part Numbers: 42700-39055 42700-39050 42700-26700 42700-3B700 42700-26500 42700-26000 42700-3B100

Also known as an inhibitor switch or transmission range sensor. It is an electronic switch mounted on the automatic transaxle that communicates gear position to the vehicle's computer.

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Apr 19, 2026

The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

Year Coverage
This article covers the Neutral Safety Switch for:
  • Kia Optima: 2001200220032004200520062007200820092010201120122013
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