Key Fob Not Working in Harrow
If your car key fob is not working, our Harrow-based auto locksmiths can diagnose and fix the fault quickly so you’re not stranded. We handle all key fob problems across the HA postcode area, from flat batteries and worn buttons to transponder and immobiliser issues, using dealer-level diagnostics and non-destructive methods wherever possible.
When You Need Help With A Key Fob That’s Not Working
A faulty car key fob can show up in different ways. Common symptoms include:
- Buttons not responding or needing to be pressed very hard
- Central locking working intermittently or on some doors only
- “Key not detected” message on push-to-start vehicles
- The car won’t start even though the blade turns in the ignition
- Red key light flashing on the dash, or immobiliser warning symbol
- Short remote range or no response unless you’re next to the car
- Remote works but boot release won’t, or vice versa
- Fob suddenly stopped working after battery change
Typical reasons your key fob is not working:
- Dead or weak fob battery
- Worn switches/buttons or cracked solder joints on the circuit board
- Water ingress or impact damage
- De-synchronised or corrupted remote coding
- Faulty transponder chip (immobiliser)
- Damaged key blade, flip hinge, or micro-switch
- Car battery low, blown fuse, or central locking module fault
- Antenna/receiver or immobiliser ring fault on the vehicle
If your fob has failed and you can’t unlock or start the car, don’t worry. Our mobile team covers Harrow, Harrow on the Hill, Wealdstone, Pinner, Stanmore, Ruislip, Northwood, Eastcote, and all HA postcodes with rapid assistance.
How We Fix Faulty Key Fobs
We bring the solution to you. Our process is thorough, transparent, and focused on getting you moving again safely.
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Quick triage on the phone
We’ll ask a few simple questions: make, model, year; what still works (locking, starting); any warning lights; whether the blade turns; and when the issue began (after a battery change, impact, or water spill). -
On-site diagnostics
- We test the fob’s battery and RF signal to confirm it’s transmitting.
- For push-to-start cars, we check proximity/comfort access functions.
- We scan the vehicle via OBD2 for immobiliser and central locking fault codes.
- Where necessary, we inspect fob internals for broken micro-switches, cracked solder, or water damage.
- The fix, tailored to the fault
- Battery replacement with the correct type, plus re-synchronisation where required.
- Key fob repair: replacing switches, housings, key blades/flip hinges, and re-soldering joints.
- Key fob programming service: re-code remotes and transponders to your vehicle using dealer-level equipment.
- Transponder key programming and immobiliser pairing if the chip has failed.
- Smart key programming for proximity/push-to-start vehicles.
- ECU/immobiliser programming or EEPROM key programming for certain models where data needs to be read/written at a deeper level.
- Where a fob is beyond repair, we provide complete key fob replacement and program it on-site.
- Verification and handover
We test lock/unlock, boot release, and starting functions, and ensure the immobiliser light behaves as expected. You’ll receive guidance on spare keys and care tips.
We use non-destructive methods wherever possible. In rare cases where a component must be opened or replaced (for example, a damaged ignition reader or a sealed smart key), we explain the options and costs clearly before any work begins.
Why Choose Our Harrow Auto Locksmiths
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Local and trusted in Harrow
We’re based in the HA area and regularly help drivers in Harrow, Harrow on the Hill, Pinner, Ruislip, Stanmore, Northwood, Eastcote, Rayners Lane, Kenton, Wembley, and surrounding neighbourhoods. -
10+ years of experience
We’ve dealt with every key fob scenario: worn buttons, water damage, immobiliser sync issues, and complex smart key faults on 2024/2025 models. -
Dealer-level tools and training
We use advanced diagnostics, OBD2 programming, and, when required, EEPROM techniques for ECU/immobiliser programming. This allows us to solve problems most “cut-only” services can’t. -
Mobile convenience
Fully equipped vans come to your vehicle—home, work, roadside—across all HA postcodes, saving you the time and cost of towing to a dealer. -
Insured and DBS-checked technicians
Your vehicle is in safe hands. We carry public liability insurance and all staff are DBS-checked. -
Non-destructive entry and repairs
We prioritise safe, non-destructive methods. If destructive steps are unavoidable, we explain them first and only proceed with your approval. -
All makes and models
From Ford, Vauxhall, Volkswagen, BMW, Audi, and Mercedes-Benz through to Toyota, Nissan, Kia, Hyundai, Peugeot, Renault, Skoda, Volvo, Land Rover, Mini, and more. -
Warranties and guarantees
Our workmanship and new keys/fobs are covered by clear guarantees for your peace of mind.
If your fob is completely dead or you’ve only got one working key left, consider arranging a spare. It’s far cheaper and faster than replacing your only key in an emergency. Learn more about our car key replacement Harrow service, or request car key programming if your fob needs re-coding.
Key Fob Repair Vs Replacement
- Repair is ideal for: worn buttons, broken flip hinges, loose battery contacts, cracked solder, and some water damage caught early.
- Replacement is best when: the PCB is severely corroded, the transponder is irreparably damaged, the fob casing is beyond saving, or the fob is lost/stolen.
We will advise honestly which route is most reliable and cost-effective for your specific vehicle and situation.
Smart Keys, Proximity Keys, And Push-To-Start Issues
Modern vehicles use sophisticated immobiliser systems. Common smart key symptoms we resolve:
- “Key not detected” despite a new battery
- Car won’t start unless the fob is held against the start button
- Doors won’t unlock on touch, but the buttons work (or vice versa)
- Intermittent starting, especially in cold or wet weather
Our approach:
- Test the fob’s low-frequency and high-frequency signals
- Check vehicle antennas (door handles, boot, interior console), start/stop button, and immobiliser ring
- Reprogram the smart key or add a new key using manufacturer-specific procedures
- Update immobiliser/BCM coding when required
For some brands and scenarios (e.g., certain Ford, BMW, Mercedes-Benz, and VAG models), EEPROM/ECU work may be needed. Our training and equipment are designed for these advanced tasks, saving you a dealer visit in many cases.
What If The Fob Works But The Car Still Won’t Start?
If the remote locks/unlocks but the engine won’t start or cuts out, it may indicate:
- Failed transponder chip in the key
- Immobiliser antenna/reader fault at the ignition
- Steering lock module failure (common on some Mercedes and VAG)
- Ignition lock or switch issues
- ECU/BCM communication errors
We can diagnose and resolve these with targeted tests and programming. See more on related faults under car lock and ignition issues.
Security After Lost Or Stolen Fobs
If your key fob has been lost or stolen, we can:
- Delete the missing key from your vehicle’s system so it can’t be used
- Supply and program replacement keys
- Re-code central locking and immobiliser data
- Advise on further security measures
Learn more about staying secure with our guidance on lost or stolen car keys.
Our Coverage Across Harrow And HA Postcodes
We provide a fast, mobile car locksmith service throughout:
- Harrow, Harrow on the Hill, West Harrow, North Harrow, South Harrow
- Wealdstone, Kenton, Belmont, Headstone, Rayners Lane
- Pinner, Eastcote, Ruislip, Ruislip Manor, Ruislip Gardens, South Ruislip
- Northwood, Northwood Hills, Hatch End, Stanmore, Canons Park
- Wembley Park, Wembley Central, North Wembley, Queensbury, Sudbury, Sudbury Hill
- Edgware, Burnt Oak, Preston, Tokyngton, Moor Park, Carpenders Park
Wherever you are in the HA postcode area, we’ll dispatch the nearest technician promptly.
Related Services And Next Steps
- Need a working spare? Arrange a visit for car key replacement Harrow so you’re covered if a fob fails again.
- If you suspect coding issues, request expert car key programming for transponders, remotes, and smart keys.
- Locked out due to a dead fob? Our vehicle unlocking service uses non-destructive entry to get you back in quickly.
- Explore the brands we cover to see how we handle Ford, Vauxhall, VW, BMW, Mercedes-Benz, Audi, Toyota, Nissan, and more.
- Can’t find your exact issue? Contact our Harrow team for friendly advice.
FAQs: Key Fob Not Working
Can a locksmith fix a key fob that’s not working?
Yes. We can replace fob batteries, repair buttons and switches, resolder joints, and reprogram both remote and transponder functions. If the fob is beyond repair, we can supply and program a new one on-site.
Why does my car say “key not detected”?
Common causes include a weak fob battery, de-synchronised smart key, interference near the vehicle, or a faulty antenna/receiver. We test both the fob and vehicle systems and reprogram as needed.
Can you program a used key fob?
Sometimes. It depends on the make/model and whether the fob can be virginised or re-locked. Many used fobs are locked to the original car. We’ll advise the best, reliable option for your vehicle.
How long does it take to fix or replace a key fob?
Most battery replacements and re-synchronisations take minutes. Repairs and programming typically take 30–60 minutes on-site. Complex immobiliser or EEPROM tasks can take longer, but we’ll explain timeframes upfront.
What should I do if my key fob got wet?
Remove the battery immediately and avoid pressing buttons. If possible, keep the fob dry and call us. Early inspection and cleaning can sometimes save the board; leaving power in the fob can cause corrosion.
Is it cheaper to repair a fob or go to a dealer?
A mobile auto locksmith is often quicker and more affordable than a main dealer, especially when the car isn’t drivable. We diagnose on-site and only recommend replacement if repair isn’t reliable. For a tailored estimate, see our guidance on auto locksmith prices Harrow.
Do you guarantee your repairs and keys?
Yes. We provide clear warranties on workmanship and new keys/fobs. We’ll confirm the details for your specific vehicle before we begin.
Genuine Customer Feedback From Harrow
- “My Audi A3 kept saying ‘key not detected’. The technician came to Harrow on the Hill, reprogrammed the smart key, and I was driving again within the hour.”
- “Buttons stopped working on our Ford Fiesta fob in Pinner. They repaired the switches and cut a spare — very professional.”
- “Ruislip Gardens — fob died after a battery swap. They re-synchronised it and checked the car’s receiver. All sorted.”
Need help now? Call 020 4630 7108 or Email us.
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