Changing your Mitsubishi key fob battery should be a straightforward task, but what happens when your key fob stops working afterward? It’s a frustrating situation, but thankfully, it’s often solvable without a costly trip to the dealership. This guide will walk you through the common reasons why your Mitsubishi key fob might fail after a battery replacement and provide step-by-step instructions to get it working again.
Common Reasons for Key Fob Issues After Battery Replacement
Before assuming the worst, let’s explore the typical culprits behind a malfunctioning key fob after a battery change:
- Incorrect Battery Installation: The most common mistake is inserting the battery with the wrong polarity (+/-). Double-check the battery orientation in the key fob casing and ensure it matches the markings.
- Low Quality or Wrong Battery Type: Using a cheap or incorrect battery type can lead to insufficient power. Refer to your owner’s manual or the markings inside the key fob for the correct battery type (usually CR2032). Ensure you use a reputable brand for optimal performance.
- Key Fob Reprogramming Needed: Some Mitsubishi models require key fob reprogramming after a battery change. This is essentially re-linking the key fob’s signal with your car’s receiver.
- Accidental Damage: While changing the battery, you might have inadvertently damaged the key fob’s internal components, especially if the casing was difficult to open.
- Underlying Key Fob Malfunction: Less frequently, the key fob might have been nearing the end of its lifespan, and the battery change was coincidental to its failure.
How to Reprogram Your Mitsubishi Key Fob
If you suspect that your key fob needs reprogramming, here’s how to do it based on the instructions from a Mitsubishi owner’s manual. Note: These steps are based on a 2009 manual and might vary slightly depending on your specific Mitsubishi model and year. Always consult your vehicle’s owner’s manual for the most accurate instructions.
- Gather Your Key Fobs: Have all your working and non-working key fobs ready that you want to program.
- Initiate Registration Mode: Using a working key fob, press and hold the UNLOCK button for 4 to 10 seconds. While still holding UNLOCK, press and hold the LOCK button.
- Release Buttons in Sequence: Within 10 seconds of pressing the LOCK button, release the LOCK and UNLOCK buttons in sequence. This is crucial and can be slightly confusing in the manual’s wording. It means release the LOCK button first, then immediately release the UNLOCK button. The car should respond with a lock and unlock cycle (answerback function), indicating registration mode is active. Important: At this stage, all previously programmed key fobs except the one you used in steps 2 and 3 are erased.
- Program Each Key Fob: Within 60 seconds of step 3, take the key fob you want to program (likely the one that stopped working after the battery change).
- Press and hold both the LOCK and UNLOCK buttons for 2 seconds.
- Release both buttons for 1 second.
- Press the UNLOCK button. The car should respond with the answerback function again, confirming successful programming of this key fob.
Alt text: Step-by-step battery replacement for a Mitsubishi key fob, a common first step in troubleshooting “mitsubishi key fob not working after battery change” issues.
- Program Additional Key Fobs (If Any): Repeat step 4 for any other key fobs you need to program within 60 seconds.
- Exit Registration Mode: If you don’t program any key fobs within 60 seconds after step 4, the car will automatically exit programming mode and return to normal operation.
Understanding Step 3: Releasing Buttons in Sequence
The manual’s wording about releasing “LOCK and UNLOCK buttons in sequence” can be misinterpreted. To clarify, it means:
- Release the LOCK button FIRST.
- Immediately AFTER releasing the LOCK button, release the UNLOCK button.
It’s a sequential release, not releasing them simultaneously. This specific sequence is important for activating the registration mode correctly.
When Reprogramming Fails
If you’ve carefully followed the reprogramming steps and your Mitsubishi key fob still isn’t working, consider these additional troubleshooting steps:
- Double-Check Battery: Ensure the battery is brand new, of the correct type (e.g., CR2032), and installed with the correct polarity. Try a different new battery from a different batch to rule out a faulty battery.
- Inspect Key Fob for Damage: Carefully examine the key fob for any signs of physical damage, especially around the battery terminals and circuit board.
- Try Again: Reprogramming can sometimes be finicky. Try the entire process again, paying close attention to timing and button sequences.
Alt text: Hands demonstrating the button sequence for Mitsubishi key fob programming, essential for resolving “mitsubishi key fob not working after battery change” problem.
Seek Professional Assistance
If you’ve exhausted all troubleshooting steps, and your Mitsubishi key fob remains unresponsive, it’s time to seek professional help. Contact your local Mitsubishi dealership or a qualified automotive locksmith. They have specialized tools and diagnostic equipment to identify and resolve more complex key fob issues, including:
- Advanced Diagnostics: They can diagnose if the issue is with the key fob itself or the car’s receiver system.
- Professional Reprogramming: They have advanced programming tools that can bypass manual programming limitations.
- Key Fob Replacement and Programming: If your key fob is damaged beyond repair, they can provide a replacement and program it to your vehicle.
Conclusion
A Mitsubishi key fob not working after a battery change is a common issue with a range of potential causes. By systematically checking the battery, attempting reprogramming, and understanding the correct button release sequence, you can often resolve the problem yourself. However, don’t hesitate to seek professional help if needed. A malfunctioning key fob is a security and convenience issue, so addressing it promptly is essential.
