Ignition Repair When the Key Will Not Turn

A large share of ignition calls are resolved in the driveway in under a minute, and none of these can do any harm.

The ignition is the lock in a vehicle that gets used more than any other, thousands of cycles a year, often with a heavy keyring hanging from it. Both the key and the cylinder wear, and they wear together.

As the cut depths on the blade round off, the key stops lifting the wafers to exactly the right heights. The driver compensates without noticing, first by jiggling, then by lifting the key slightly, then by finding the one position where it works. By the time it stops entirely, the key has often been marginal for a year.

The important point is that a worn key accelerates wear in the cylinder, because misaligned wafers get dragged past the shear line every single time. Cutting a fresh key from the vehicle's code, which produces a correct key rather than a copy of a worn one, is cheap and frequently ends the problem outright. It is always worth trying before condemning the cylinder.

A heavy keyring is the other avoidable cause. Several kilograms of keys, fobs and trinkets hanging off the ignition puts constant downward load on the cylinder and the switch behind it, and it is a genuine contributor to premature failure.

The ignition is two components that people talk about as one. The cylinder is the lock you put the key into. The switch is the electrical part behind it that the cylinder rotates. Which one has failed is usually clear from the symptom.

When a cylinder genuinely has to be replaced, there is a choice that is worth understanding because it affects how many keys you end up carrying.

A new cylinder arrives with its own keys. If it is simply fitted as supplied, the vehicle then needs one key for the ignition and a different key for the doors and boot, which is a nuisance for the rest of the car's life.

The better outcome is to rekey the new cylinder to match your existing door key, so one key continues to run the whole vehicle. That is standard practice and it is worth asking for explicitly. On some vehicles the alternative is to rekey the doors to the new cylinder instead, which achieves the same single key result.

Whichever route, the transponder side still has to be handled. If the ignition cylinder is replaced, the key that turns it must still be programmed to the immobiliser, so this is generally a combined mechanical and programming job.

Some ignition faults are not really ignition faults. On many vehicles the ignition assembly is integrated with the steering column lock, and on newer cars that assembly is an electronic steering lock module rather than a mechanical pin.

A failed electronic steering column lock produces a dramatic symptom: the car is completely immobilised, often with the wheel locked, and no key or fob will free it. That is a module replacement and, on several makes, a dealer level operation because the module has to be coded to the vehicle.

Similarly, if the fault turns out to be in the wiring loom, the body control module or the starter circuit, it is an automotive electrical job rather than a lock job. We would rather diagnose that at the roadside and tell you plainly than replace a perfectly good cylinder and leave you with the same problem.