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2020 Santa Fe SE Key Fob Not Working / Push Start Issues

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Brittany E. · rep 0 · May 22, 3:01 AM · 1 replies · solved · Question

Vehicle: 2020 Hyundai Santa Fe SE

My 2020 Hyundai Santa Fe SE is giving me trouble with the key fob and push-button start. Sometimes, the car just won't recognize the key fob, even when it's right there in the cup holder. I get a 'Key Not Detected' message on the dash.

I've tried replacing the battery in the fob, but the problem still happens intermittently. It's really frustrating when I'm trying to leave for work. Is this a common issue with the Santa Fe? Could it be the car's battery, or something more serious with the immobilizer system?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:01 AM

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ClearTheCode admin answer:

It sounds like your 2020 Hyundai Santa Fe SE is experiencing an intermittent 'Key Not Detected' issue, which can be incredibly frustrating. This problem typically points to communication issues between your key fob and the vehicle's immobilizer and smart key system.

Common Causes:

  • Key Fob Battery (Even New Ones): While you replaced it, ensure it's a fresh, high-quality battery and inserted correctly. Low-quality or old 'new' batteries can still cause issues.
  • Interference: Strong electromagnetic interference from nearby cell towers, power lines, or even other electronic devices in your car (like dash cams or phone chargers) can sometimes disrupt the signal.
  • Vehicle's 12V Battery: A weak or dying 12V car battery can cause a myriad of electrical gremlins, including issues with the smart key system.
  • Key Fob Malfunction: The fob itself might be faulty or damaged (e.g., from dropping it).
  • Smart Key Antenna/Receiver: The vehicle has antennas that pick up the fob's signal. If one of these is faulty or obstructed, it can cause detection problems.
  • Immobilizer System Issue: Less common, but a fault in the vehicle's immobilizer or Body Control Module (BCM) could be the root cause.

Troubleshooting Steps:

  1. Try the Second Fob: If you have a second key fob, try using it exclusively for a few days. If the problem disappears, your primary fob might be faulty.
  2. Reposition the Fob: When starting, try holding the fob directly against the push-button start button. This uses a closer-range RFID chip in the fob and can sometimes bypass signal issues.
  3. Check Vehicle Battery: Have your vehicle's 12V battery tested at an auto parts store. A weak battery can cause inconsistent electrical behavior.
  4. Remove Potential Interference: Temporarily remove or turn off any aftermarket electronic devices in your car to see if they are causing interference.
  5. Inspect Fob for Damage: Check your primary key fob for any physical damage or signs of water intrusion.

When to See a Shop:

If none of the above steps resolve the issue, or if both key fobs exhibit the same problem, it's crucial to take your Santa Fe to a Hyundai dealership. They have specialized diagnostic tools to check the smart key system, immobilizer, and BCM for fault codes or malfunctions. They can also reprogram key fobs or replace faulty antennas/modules if necessary. Since this is a safety and convenience issue, addressing it promptly is important.

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