Citroën All Keys Lost: What’s Involved

Lost or had stolen every key to your Citroën? It is a horrible moment — the car is immobilised, and if it came with just one key there is nothing to fall back on. The reassuring part: an all-keys-lost Citroën is a routine job for a specialist, and we almost always do it where the car is parked — your drive, a car park, the roadside — with no recovery to a dealer. Here is what the job actually involves.

Why all-keys-lost is a bigger job than a spare

With one working key still in hand, adding a spare is simple: the car opens, starts and already trusts an existing key. All-keys-lost takes all of that away — no key to open the doors, no key to start the engine, and nothing the immobiliser currently recognises. Everything has to be rebuilt from scratch, which is why it takes longer and costs more than a spare.

The BSI and the security PIN are the heart of it

Citroën runs its immobiliser through the BSI — the Built-in Systems Interface, the central body-control unit — and every car has a security PIN stored against it. To code a new key with no working key present, that PIN has to be established, which on most Citroëns we read or calculate by OBD with dealer-level equipment. Only once the BSI accepts the PIN will it let us write a new key into the car. That PIN work is the specialist part, and it is why a high-street cutter cannot do all-keys-lost. If you want the underlying detail, our Citroën key programming and VA2-vs-HU83 guide explains the blades, chips and BSI in full.

What happens at the roadside, step by step

• Non-destructive entry: we open the car without drilling or breaking glass — no damage to the vehicle.
• Establish the security PIN: with Citroën dealer-level software and the car’s diagnostics, we read or calculate the PIN the BSI needs.
• Cut the blade: we cut the VA2 or HU83 blade — or the emergency blade inside a proximity fob — to your car.
• Code the new key: the key’s identity is written into the BSI so the immobiliser trusts it.
• Test and hand over: the key locks, unlocks and starts the engine before we leave.

Older Hitag2 vs newer AES cars

On older Hitag2 (ID46) Citroëns — many C1, C3 and C4 cars up to around 2018 — all-keys-lost is well-trodden ground. On the newest secure Hitag AES cars (current C3, new C4 and their keyless fobs) it needs current software and the correct blank, and a keyless car means a proximity fob rather than a flip key. So the year of your Citroën, not just the model, sets the job [verify against your VIN] — the same PSA-versus-Stellantis split that runs across the whole group.

First — is the key really lost?

Before assuming the worst, rule out the cheap explanations. If the key is in your pocket but the car will not read it, you may simply have a flat fob battery or a key that has stopped responding — not an all-keys-lost. Our Citroën key programming guide covers those. All-keys-lost only applies when every key is genuinely gone.

If your keys were stolen

A stolen key is handled differently from a lost one, because the missing key can in principle still start the car. As well as coding a new key we make sure the old one is dealt with — see our stolen car keys service alongside the lost keys one.

The honest cost picture

An all-keys-lost costs more than a spare because of the new key, the PIN work and the time involved — and a secure AES key on a newer Citroën costs more than an older Hitag2 one. We will not invent a figure here: it depends on your exact car and key type, so tell us your registration and we will confirm the price before we travel. No towing bill, no dealer wait.

Get back on the road

If you have lost every key to your Citroën, our lost car keys and key programming service replaces and codes a new key at the roadside across Bristol, Bath and South Gloucestershire — for the C1, C3, C4, C3 Aircross and C4 Cactus. See the Citroën key replacement hub for the full range. Call 07967 097 899, Monday to Friday, 8am–5:30pm.