Why wont my remote start work on my key fob?

A remote start often fails due to a weak key fob battery, an inactive or incompatible remote-start system, or safety checks that aren’t being met. In many cases, replacing the battery, confirming the feature is enabled, and using the correct start sequence fixes the issue.

This article explains the typical reasons remote start might fail, how to troubleshoot, and when to seek professional help. It lays out common causes and a practical step-by-step approach so you can diagnose the problem efficiently.

Common reasons remote start fails

Understanding the main issues helps you target the problem quickly.

Factory-installed vs aftermarket considerations

Some cars include remote start as a factory option or on higher trims, while others rely on aftermarket modules. Availability, activation, and compatibility differ by model and may require dealer activation or professional installation.

• Dead or weak key fob battery, which prevents the car from receiving the start command.


• Remote start not installed or not enabled on the vehicle, or the feature is restricted to certain trims or markets.


• Safety checks not satisfied, such as doors not locked, the vehicle not in Park, the hood being up, or the brake not pressed during the start command.


• Key not recognized by the immobilizer or a faulty/undetected key, triggering an anti-theft response.


• Vehicle battery or electrical system too weak, causing the remote start system to abort for safety.


• Operating range or signal interference from metal surfaces, other remotes, or electronics that block the signal.


• Aftermarket remote start installation issues or incompatibilities with the vehicle's factory security system.


• Anti-theft or security features kicking in, preventing a remote start when the system detects a potential theft risk.

Most remote start failures fall into one of these categories. If you’re unsure which applies to your car, start with the fob battery and system activation questions before moving on to more complex diagnostics.

Troubleshooting steps you can take

Proceed in order from the simplest checks to more involved diagnostics.

1. Test or replace the key fob battery. If you have a spare key fob, try that one too to see if the issue is specific to a single fob.


2. Verify that your vehicle supports remote start and that it is enabled in the settings or by a dealership. Some trims require activation with the dealer or a software update.


3. Confirm the safety prerequisites for a remote start are met: doors are locked, transmission is in Park, the hood is closed, and you’re not pressing the brake when starting.


4. Check the vehicle’s 12-volt battery and overall electrical health. A weak battery can prevent the remote start from operating or trigger safety protections.


5. Consider immobilizer/key recognition issues. If the car doesn’t recognize the key, remote start won’t engage. Try a spare key if available and have the immobilizer reprogrammed if necessary.


6. Test the range and look for signal interference. Move closer to the vehicle and remove potential sources of interference (heavy metal surroundings, other remotes, or RFID blockers).


7. For vehicles with smartphone or app-based remote start, ensure the app is up to date, linked to your car, and has the necessary permissions and network access.


8. Scan for fault codes or dashboard lights that may indicate a fault in the starting system, immobilizer, or body control module. A professional scan tool can help identify the root cause.

If the remote start still won’t operate after these steps, contact your dealer or a qualified automotive technician. They can check for software updates, reprogram the key, or diagnose a failing remote start module or immobilizer issue.

In addition, never start a vehicle remotely in a closed garage or enclosed space. Remote starting emits exhaust and can create dangerous CO buildup in an enclosed area.

Summary

Remote start problems are usually solvable with a few basic checks: replace a dead key fob battery, confirm the feature is enabled for your model, ensure safety prerequisites are met, and rule out battery or immobilizer issues. If DIY steps do not resolve the issue, professional assistance is advised to protect your vehicle’s security and electrical system.

Why is my remote start not working on my key fob?

If your key fob remote start isn't working, the most common reasons are a dead key fob battery, the vehicle not being in park, or a safety interlock like an unlatched hood or open door. First, check the vehicle's status (is the hood closed? is it in park?), then try replacing the key fob battery. If that doesn't work, you may need to reprogram the fob or check for other issues like a blown fuse, a faulty hood pin switch, or a "check engine" light.
 
Vehicle status and safety checks

• Ensure the vehicle is in park: The car will not remote start if it isn't fully in park. 
• Check the hood: Make sure the hood is completely closed. An unlatched hood, even if it appears closed, will disable the remote start. 
• Close all doors: All doors, including the trunk and any other doors, must be shut. 
• Check for warning lights: A "check engine" light or other warning lights can prevent the remote start from working. 
• Check your manual: Your car's manual will have specific requirements for your vehicle's remote start system. 

Key fob and remote start system issues

• Replace the key fob battery: A weak or dead battery is the most frequent and easiest fix. Try replacing the battery, as it may have enough power for locking/unlocking but not for the longer-range remote start signal, say Batteries Plus and Chapel Hill Tire. 
• Check the "lock" button: Many systems require you to press the "lock" button on the fob before you can start the engine. If this button is also not working, it's a strong indicator of a key fob issue. 
• Reprogram the key fob: The fob may need to be reprogrammed to the vehicle. This is often necessary after a battery change or if the signal is lost. 
• Inspect for physical damage: Look for any physical damage to the key fob, such as cracks or worn buttons, that could be interfering with its functionality. 

Advanced and other potential issues

• Check the vehicle's battery: A very low car battery voltage can prevent the remote start from working. 
• Look for a blown fuse: A blown fuse for the keyless entry or remote start system can cause it to stop working. 
• Service the hood pin switch: The hood pin switch is a safety sensor. If it's faulty and thinks the hood is open when it is not, it will disable the remote start. 
• Address valet mode: Some vehicles have a "valet mode" that disables the remote start. Refer to your owner's manual to see how to disable it. 
• Consult a professional: If you have tried all of the above and it still doesn't work, there may be an internal issue with the remote start module or a faulty antenna. A professional can diagnose these more complex problems. 

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How to reset remote starter fob?

Resetting Your Remote Starter
Grab all of your car's remote-start fobs. While in the driver's seat, close the driver's side door. Insert your ignition key and turn it to Accessory (or press the start button once without pushing the brake pedal). Press the Lock button on your remote car starter.

What to do when a car won't start with a key fob?

Try to push the start button with the key fob, if it still says it can't detect it, the battery in your fob needs to be replaced. If your car does detect the key, and still won't start, go grab some jumper cables and a buddies car or a booster pack. Jump it, then let it run with the hazard lights on for 30-45 minutes.

How do I activate remote start on my key fob?

Times. Once started remotely the engine will run for 10 minutes and then shut. Off. You can extend the running time for another 10 minutes by repeating the start procedure during the initial. Period.