# 2017 Land Cruiser: Key Fob Not Detected, Car Won't Start

> ClearTheCode — Facing a 'Key Fob Not Detected Message, Car Won't Start' in your 2017 Toyota Land Cruiser? Discover common causes and troubleshooting steps to get your SUV running again.

Source: https://clearthecode.com/articles/key-fob-not-detected-start-car-toyota-land-cruiser-2017
Author: ClearTheCode

# Key Fob Not Detected Message, Car Won't Start 2017 Toyota Land Cruiser

Experiencing a 'Key Fob Not Detected Message, Car Won't Start' in your 2017 Toyota Land Cruiser can be incredibly frustrating. You're ready to go, the key fob is in your pocket or hand, yet your luxurious SUV refuses to acknowledge its presence, leaving you stranded. This isn't just an inconvenience; it's a complete halt to your plans, often without a clear indication of why your Land Cruiser has suddenly become unresponsive to its own key.

## What drivers notice on this 2017 Toyota Land Cruiser

When your 2017 Toyota Land Cruiser displays the "Key Fob Not Detected" message, the most immediate and impactful symptom is the inability to start the engine. Despite pressing the push-button start, the vehicle remains stubbornly off, often without even engaging accessory power. This issue can manifest suddenly, turning a routine start-up into a puzzling diagnostic challenge. Owners might also notice that other key fob functions, such as remote locking and unlocking, may or may not work, adding to the confusion.

## At a glance: difficulty, repair cost, and diagnostic workflow

- **Difficulty Rating:** 6/10 — Moderate
- **Common Symptoms:** "Key Fob Not Detected" message: This is the primary alert displayed on the multi-information display.; Engine does not crank or start: The push-button start system remains inactive, and the engine will not turn over.; Push-button start light behavior: The start button's illumination might not change from amber to green when the brake is; No accessory power: Attempting to start may not even activate the vehicle's accessory systems (radio, power windows, etc
- **Estimated Repair Cost:** $100–$900 (parts + typical shop labor)
- **OEM Tooling Required:** Standard OBD-II scanner and hand tools

**Diagnostic workflow:**
1. Confirm the symptom on your vehicle.
2. Scan for stored or pending codes with an OBD-II tool.
3. Inspect the most common causes in this guide (visual checks first).
4. Run verification tests before replacing parts.
5. Repair, clear codes, and verify on a test drive.

## Symptoms and warning signs

Beyond the primary message, several other indicators can accompany or precede the full failure:

-   **"Key Fob Not Detected" message:** This is the primary alert displayed on the multi-information display.
-   **Engine does not crank or start:** The push-button start system remains inactive, and the engine will not turn over.
-   **Push-button start light behavior:** The start button's illumination might not change from amber to green when the brake is pressed, or it might flash amber, indicating a problem.
-   **No accessory power:** Attempting to start may not even activate the vehicle's accessory systems (radio, power windows, etc.) that typically come on with the first press of the start button.
-   **Intermittent issues:** Before complete failure, you might experience occasional delays in recognition or the message appearing sporadically.
-   **Remote functions may or may not work:** The ability to lock/unlock doors remotely can sometimes still function even if the vehicle won't start, or it might also be affected.

## How to verify and confirm the issue

Confirming the root cause of a "Key Fob Not Detected" message in your 2017 Land Cruiser involves a series of practical checks:

-   **Replace the key fob battery:** This is the most common culprit. The 2017 Land Cruiser key fob typically uses a CR2032 coin cell battery. Replace it with a fresh, high-quality battery. Even if remote functions work, the signal strength for starting might be too weak.
-   **Try your spare key fob:** If you have a second key fob, try using it. If the spare works, it strongly suggests an issue with the original fob or its battery.
-   **Hold the fob against the start button:** Toyota vehicles often have a manual override. With the brake pedal pressed, hold the key fob directly against the push-button start. The vehicle's immobilizer system has an antenna in or near the button that can read the fob's chip even if its battery is dead.
-   **Check the vehicle's 12V battery:** A weak or dying main vehicle battery can also cause issues with the smart key system, as it relies on stable voltage. Test the battery voltage; anything below 12.0V could be problematic. You can find more comprehensive repair guides for battery issues.
-   **Check for electromagnetic interference:** Strong radio signals or electronic devices (e.g., cell phones, laptops, certain chargers) near the key fob or the vehicle's smart key antenna can interfere with communication. Try moving the vehicle or the fob away from potential sources.
-   **Visual inspection of the key fob:** Look for any signs of physical damage, water intrusion, or corrosion on the fob itself.
-   **Inspect relevant fuses:** Consult your owner's manual for fuses related to the smart key system, immobilizer, and ECU-B (body control module). A blown fuse can interrupt power to these critical components.

## Common causes (most likely first)

Understanding the potential causes can help narrow down the diagnosis:

-   **Dead or weak key fob battery:** By far the most frequent reason. The fob's battery powers the transmitter that communicates with the vehicle.
-   **Weak or dead 12V vehicle battery:** The vehicle's main battery powers the smart key receiver and immobilizer system. Low voltage can cause communication failures.
-   **Electromagnetic interference:** External radio frequency (RF) signals can disrupt the communication between the fob and the vehicle.
-   **Faulty key fob:** The fob itself might be damaged internally, preventing it from transmitting a proper signal, even with a new battery.
-   **Problem with the Smart Key ECU/receiver:** The vehicle's smart key electronic control unit (ECU) or its antenna, responsible for receiving the fob's signal, could be malfunctioning.
-   **Wiring issues or blown fuses:** Damaged wiring or a blown fuse in the smart key or immobilizer circuit can cut power or data flow.
-   **Immobilizer system malfunction:** The vehicle's anti-theft immobilizer system, which works in conjunction with the smart key, might have a fault preventing engine start.

### Related guides on this vehicle

- [AC Blowing Hot Air When Car Is Idling 2017 Toyota Land Cruiser](/articles/ac-blowing-hot-air-when-idle-toyota-land-cruiser-2017)
- [Car Won't Start, No Click, No Crank 2017 Toyota Rav4 Diagnosis](/articles/car-wont-start-no-click-no-crank-toyota-rav4-2017)
- [2017 Toyota Tundra Won't Start, Security Light Flashing](/articles/car-wont-start-security-light-8652-toyota-tundra-2017)

## Step-by-step diagnosis and fixes

Follow these steps to diagnose and potentially fix the issue:

1.  **Start with the simplest fix: Replace the key fob battery.** Ensure you use a fresh, reputable brand CR2032 battery. Test the vehicle immediately after.
2.  **Try your spare key fob.** If the spare works, the problem is definitely with the original fob.
3.  **Perform the manual override.** Hold the non-working fob directly against the push-button start while pressing the brake. If the vehicle starts, it indicates the fob's battery is too weak for regular transmission, or there's significant interference.
4.  **Check the vehicle's main 12V battery.** Ensure it's fully charged and in good health. A simple voltage test with a multimeter should show above 12.4V. If it's low, charge or replace it.
5.  **Relocate the vehicle/fob.** Move your Land Cruiser to a different spot, away from large electronic devices or high-power radio transmitters, to rule out interference.
6.  **Inspect relevant fuses.** Refer to your owner's manual for the fuse box locations (usually under the hood and in the cabin) and identify fuses related to the smart key, immobilizer, and ECU-B. Replace any blown fuses.
7.  **Inspect the key fob for damage.** If the fob has been dropped or exposed to moisture, internal damage could be the cause. Consider opening it carefully (if possible) to check for corrosion.
8.  **Professional scan tool diagnosis.** If all the above steps fail, a diagnostic scan tool capable of communicating with Toyota's smart key and immobilizer systems can read specific trouble codes or live data that might pinpoint a faulty ECU, antenna, or wiring issue. This step is crucial before considering expensive component replacements.

## Repair options and cost factors

The cost and complexity of repairs vary significantly depending on the root cause:

-   **Key fob battery replacement:** This is the least expensive option, typically costing a few dollars for the battery, and is a simple DIY task.
-   **Vehicle 12V battery replacement:** Costs range from $150-$300 for a new battery, plus potential installation if done professionally.
-   **New key fob:** If the original fob is faulty, a new one can be expensive, often $250-$400 or more. This usually requires programming by a Toyota dealership or a specialized automotive locksmith, which adds to the cost (typically $100-$200 for programming).
-   **Smart Key ECU/receiver replacement:** This is a more complex and costly repair, potentially ranging from $500-$1500 or more for parts and labor, as it often requires specialized programming and calibration by a dealership.
-   **Wiring repair:** Costs are highly variable, depending on the location and extent of the damage. Simple repairs might be under $100, while complex harness issues could be several hundred dollars.
-   **Immobilizer system repair:** This can involve replacing components within the immobilizer system or reprogramming, with costs similar to or higher than a Smart Key ECU replacement.

## When to see a professional

While many initial troubleshooting steps can be performed by the owner, there are clear indicators for when professional assistance is necessary:

-   If replacing the key fob battery and trying the manual override doesn't resolve the issue.
-   If you've tested your vehicle's 12V battery and confirmed it's good, but the problem persists.
-   If you don't have a spare key fob to test, making it difficult to isolate the problem to the fob itself.
-   When multiple key fobs fail to work, suggesting a vehicle-side problem (ECU, antenna, wiring).
-   If you suspect an issue with the vehicle's immobilizer system or Smart Key ECU.
-   When diagnostic trouble codes (DTCs) related to the immobilizer or smart key system are present and require specialized tools to interpret or clear.
-   For key fob programming or replacement of smart key system components, which often require dealer-level tools and expertise. You can find more information on various vehicle systems by browsing our [vehicle-specific articles](/vehicles).

## Frequently asked questions

### Why does my 2017 Land Cruiser say "Key Fob Not Detected" even with a new battery?

Even with a new key fob battery, the message can appear due to several reasons. The vehicle's main 12V battery might be weak, or there could be electromagnetic interference blocking the signal. Less commonly, the key fob itself could be faulty internally, or there might be an issue with the vehicle's smart key receiver or immobilizer system.

### Can I start my 2017 Land Cruiser if the key fob battery is dead?

Yes, you can often start your 2017 Toyota Land Cruiser even if the key fob battery is dead. Toyota vehicles typically have a manual override function. You need to press the brake pedal and then hold the key fob directly against the push-button start. This allows the vehicle's immobilizer system to read the fob's chip through a short-range antenna.

### How do I reprogram a new key fob for my 2017 Toyota Land Cruiser?

Reprogramming a new key fob for a 2017 Toyota Land Cruiser typically requires specialized diagnostic equipment that communicates with the vehicle's immobilizer and smart key ECU. This process is usually performed by a Toyota dealership or a qualified automotive locksmith, as it's not a simple DIY procedure like some older keyless entry remotes.

## Sources and further reading

-   2017 Toyota Land Cruiser Owner's Manual
-   Toyota Technical Service Bulletins (TSBs) related to smart key systems
-   Automotive diagnostic and repair forums

This information is provided for general guidance and is not a substitute for OEM service procedures. Always consult your vehicle's service manual and use a qualified technician for safety-critical work.

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