Push-Button Start “Key Not Detected” Fix

By the Radman Auto Repair team, independent auto repair in Etobicoke since 1999 · Updated November 2026

Push-button start cars need to sense the key fob before they start. A weak fob battery, interference from phones or chargers, or a weak 12V battery can cause “Key not detected” or “Key not found”, often on cold mornings.

Symptoms

What Causes It

Before You Start

• Park on level ground, set the parking brake and chock the wheels. Never work under a car held up only by a jack: use rated jack stands.
• Let the engine and exhaust cool before you touch them; coolant systems are under pressure when hot.
• Wear safety glasses and gloves, and disconnect the 12V battery before unplugging electrical parts or working near airbags.
• Check for open recalls on your VIN (Transport Canada or the manufacturer’s site) before you buy parts: a recall repair is free at the dealer.
• Use the correct battery and fit it the right way up.

Step-by-Step: Key Not Detected

1. Use backup start. Hold the fob against the start button and press it (on some Nissans, insert the fob in the slot).
2. Replace the fob battery. Open the fob and replace the coin battery.
3. Remove interference. Keep the fob away from phones, chargers and other fobs.
4. Try the spare. If the spare fob works, the first fob is the problem.
5. Test the car battery. Test the 12V battery; a weak one can cause this.
6. Book diagnosis. If it continues, have the key antenna and system scanned.

When to Stop and Bring It In

• Neither fob works.
• The car won’t start even with the fob on the button.
• The 12V battery keeps going flat.
• You need a new fob programmed.

Not sure, or out of time? Radman Auto Repair in Etobicoke does this repair every week. Book online or call (416) 742-4521.

Also Known As

Searched as “key not detected”, “Nissan key not detected”, “Honda key not detected”, “Toyota key not found”, “push button start won’t start”, “key fob battery replacement” and “smart key not detected”.

Frequently Asked Questions

See also Battery Test & Replacement, Car Won’t Start, Electrical Diagnostics, Dashboard Warning Lights Guide.

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Alex Joseph

11:02 10 Oct 26

Alex is a great guy. He took the time to respond by phone and walk me through my options for my Tesla Model Y 2024 and gave me his perspectives as a Tesla owner. Top recommendation in my books for the Toronto area.

France T

20:58 31 Aug 26

I cannot say enough good things about Livio and the team at Radman Auto Repair in Rexdale. We brought in my son’s 2015 Mitsubishi Lancer because the A/C was malfunctioning. We had already been to two other shops, paid for diagnostics, and received different explanations, so we were frustrated and unsure what to do next. Livio was outstanding. He listened carefully, looked at the issue, and explained everything clearly and in detail in a way that actually made sense. He was able to narrow down what was going on within minutes, without guessing, pressure, or recommending unnecessary work. What really stood out was that he did not charge us another diagnostic fee after learning we had already paid for two separate diagnoses. Even better, the work was completed the same day, which was a huge relief. It is rare to find a mechanic who is knowledgeable, honest, patient, efficient, and genuinely focused on helping customers understand the real issue before they spend money on repairs. Livio truly gets it. We are so happy we found Radman Auto Repair and would highly recommend Livio and his team to anyone looking for trustworthy, skilled, and customer-focused service..

Roney Zachariah

04:42 10 Aug 26

My 2015 Honda CR-V was blowing hot air and making noise when the A/C was on. The Compressor and Expansion valve needed replacement due to metal debris in the system. I rarely write reviews, but I felt it would be wrong not to appreciate Radman for their service, especially after what I went through before finding them. I’m writing this one month after the repair because I wanted to test my A/C on multiple long trips before recommending them. One thing I learned from this experience is that many mechanics know how to replace parts, but very *few follow the right procedures* and perform the proper checks. I initially went for a cheaper repair at a local mechanic. The problem came back, and afterward he didn’t seem to know what to do next. I found Radman through Google reviews without any personal recommendation, so I was taking a chance. They properly diagnosed the issue, explained everything clearly before starting the work, didn’t exaggerate the problem, and charged me a reasonable price. A/C issues can be complicated but they answered all my questions and I honestly haven’t had such a good and detailed conversation with a mechanic in the GTA about an A/C problem. Their knowledge and experience with A/C systems really stood out. I also had a catalytic converter issue. Another mechanic simply recommended replacing it, which would have cost at least $2,000. Radman explained that considering the age and condition of my 2015 CR-V, such an expensive replacement might not make sense. They gave me the replacement cost but also suggested trying Cataclean first. I tried it, and so far I haven’t had any issues. After a month and several long trips, my A/C is still working well. It’s rare to find this combination of knowledge, transparency, and honesty. Thank you, Radman, for the knowledgeable and honest service. I genuinely appreciate it.

Moklas Salkon

17:17 23 Jun 26

I fix my cars myself but I always go to Radman for AC work. Been coming here for years and they do great work and are fairly priced. The guys are honest and reliable. Very clean waiting room too!

Alexa De Los Santos

18:30 26 May 26

Finding a mechanic who actually understands EVs and is completely trustworthy is hard to come by, but ⁠Radman Repair is excellent. The service was top-notch, they explained everything to me with so much patience, and the overall experience was a 10/10. 100% recommended!

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