- Onboard learn procedures often erase keys that were not present. Cycle every key the customer owns.
- Security access delays are a designed anti theft feature. Quote them in advance.
- Support the battery during programming. A voltage drop mid write can brick a module.
- Module reading is real risk work. Practice on scrap before a customer's car.
Onboard procedures
Some vehicles let you add a key without any tool at all, provided you already hold two working keys. The typical pattern is insert key one, turn to run, remove, insert key two within a few seconds, turn to run, remove, then insert the new key. A security light flashes to confirm the module has entered learn mode and again to confirm the new key was accepted.
Onboard procedures are free, fast and unglamorous, and they are also the reason a customer with two keys should almost never pay full programming price for a third. Being honest about that builds the kind of reputation that fills a schedule.
The catch is that onboard learning frequently erases every key that was not present during the session. Always cycle every key the customer owns through the procedure, and always ask whether a key is sitting in a drawer at home before you start.
Diagnostic programming and security delays
With no working key you connect a programmer to the diagnostic port and ask the immobiliser to accept a new identity. Manufacturers guard that request with a security access delay, historically ten minutes on Chrysler products, sixteen minutes on many Fords, and up to an hour on some European platforms. The delay is deliberate. It makes opportunistic theft impractical while leaving legitimate service possible.
Budget the wait into your quote and tell the customer about it before you start rather than after. A customer told up front that the car has a sixteen minute security timer treats it as expertise. The same customer discovering it at minute twelve treats it as stalling.
During the delay keep the battery supported. A programmer holding the bus awake plus a car sitting in the run position will drain a marginal battery, and a voltage drop partway through a module write is the one failure that turns a routine job into a tow.
When the module has to come out
Some platforms will not surrender a PIN or a security code over the diagnostic port at all. On those you read the immobiliser or body control module directly, either on the bench through its connector pins or in circuit through a bootloader connection. The read gives you the stored key data, from which the tool derives what it needs.
This is advanced work with real risk. A misread pinout or a slipped probe can corrupt a module that costs more than the whole job. Practice on scrap modules before you practice on a customer.
Know your limit and price the alternative honestly. Telling a customer that this particular car is a dealer job is not a failure. It is the judgment that stops a four hundred dollar key from becoming a two thousand dollar module.
Common Questions
Does programming a new key erase my old ones?
Sometimes, and on many vehicles it is the safest choice. If you bought the car used or lost a key you cannot account for, ask for all previous keys to be erased so a missing key cannot start it.
Why does a dealer want the car towed in and a locksmith does not?
A mobile automotive locksmith carries the same diagnostic tools and the key blanks in the van. The work happens where the car is, which is usually cheaper than a tow plus dealer labor.
How long does programming take?
Often under half an hour once the key is cut. Some makers enforce a security wait of ten to thirty minutes before a new key is accepted, and that wait cannot be skipped by anyone.
Rather hire someone for this?
The directory lists automotive locksmith businesses by city, each with a phone number and its public reviews.
Find a automotive locksmithWhat the specialist badge means