Program the Remote Key

Last updated: June 7, 2026

If the remote on your Toyota Aygo B40 (2014–2021) has stopped locking the car — after a flat fob battery, a second-hand key, or it simply losing sync — you can often re-register the remote yourself, with no diagnostic tool. The Aygo uses Toyota’s door-and-ignition programming sequence. It looks fiddly written down, but it’s just a precise series of door and key actions. Here’s exactly how.

What This Does (and Doesn’t) Cover

This registers the remote (central-locking) function of a key the car can already start, or re-pairs one that has lost sync. It does not code a brand-new transponder for a lost key — that needs Toyota/dealer equipment because of the immobiliser. Up to 4 remotes can be registered.

The four modes

• Add — register a new remote while keeping the existing ones.
• Rewrite — erase all stored remotes and register from scratch.
• Confirmation — check how many remotes are currently registered.
• Prohibition — erase all stored remotes (use if a key is lost).

Before You Start

• Remove the key from the ignition.
• Driver’s door open and unlocked; all other doors closed and locked.
• Each numbered group below is time-limited — work briskly and have the fob ready.

Programming the Remote

1. Within 5 seconds: insert the key into the ignition and remove it. Then insert and remove it again.
2. Within 40 seconds: close the driver’s door, open it, close it, open it. Then insert the key and remove it.
3. Within 40 seconds: close the driver’s door, open, close, open. Insert the key, then close the driver’s door.
4. Select the mode (within 40 seconds): turn the ignition from LOCK to ON and back at 1-second intervals, repeating the number of times for your mode — Add: once, Rewrite: twice, Confirmation: 3×, Prohibition: 5×. Remove the key.
5. Confirmation: within 45 seconds the door locks cycle to show the mode was entered (Add once, Rewrite twice, Prohibition 5×).
6. Register the fob: press the lock and unlock buttons together for 1.5 seconds, then press lock once. Within 5 seconds the door locks operate once — the remote is registered. (If they operate twice, it failed — start again.)
7. More remotes? The mode stays active for 40 seconds — repeat step 6 for each additional fob.
8. Finish: open the driver’s door and insert the key into the ignition.

If It Won’t Take

• Two lock cycles = failure — one missed step or a timing overrun resets it; begin again from the start.
• Fit a fresh fob battery first — a weak cell can make registration fail (the Aygo smart key uses a CR1632; the standard remote a CR2016).
• Doors must be in the right state throughout — driver’s open/unlocked, the rest closed/locked.
• Lost key, or need a new transponder? That part needs a dealer or auto-locksmith — the immobiliser side can’t be done at home.

Frequently Asked Questions

Can I program a Toyota Aygo remote without going to a dealer?

Yes — the remote (locking) function re-registers with the door/ignition sequence above. Only a brand-new transponder key for a lost key needs a dealer.

How do I know it worked?

After pressing lock+unlock then lock, the door locks operate once within 5 seconds. Two operations means it failed.

How many remotes can I register?

Up to four. Use “Add” mode to keep existing ones, or “Rewrite” to clear and start fresh.

The remote still won’t work — what next?

Fit a fresh cell (CR1632 smart key / CR2016 standard) and retry; if it still fails, the fob or receiver may be faulty — a stored code can be checked on autodtcs.com.

If the remote stopped after the fob battery died, start with our Aygo key fob battery replacement guide, then re-register it using the steps above.