These are the central locking faults owners reported and what fixed them. Not every case was solved. For what the parts are, see Central locking and alarm: what your car has.
Match your symptom
| Symptom | What fixed it (owner reports) |
|---|---|
| Fob locks, but won't unlock; the door pins lift only weakly or twitch. Steering column switch behaves the same way | New CDL module (one 2010 case began after a few main battery discharges, and the unit gave a strong lock but a weak unlock). |
| Alarm arms but the doors won't lock; the pins twitch. The doors can still be pushed down by hand, and unlock fine | New CDL module (two owners). Another owner opened his CDL module and found one of two relays open circuit; he swapped it for a few pounds and it worked. |
| Won't lock from the fob but locks and unlocks from the steering column switch; the pins don't twitch at all | A 2017 owner tested his CDL module and found it fine. The supplier said the alarm unit was at fault, and a replacement alarm unit fixed it. |
| Switch works fully, fob locks but won't unlock (indicators flash and the alarm disarms) | Unresolved in the threads. One owner (2014) changed the CDL module and the inertia relay in the passenger footwell without luck; another had the same problem in 2016. |
| Nothing moves at all | A 2014 owner locked out of his car suspected the CDL module; another owner who had the same lock-out said his turned out to be a failed CDL module. |
| Fob won't lock on an NA that has had central locking fitted | Graphite spray on the white plastic tabs and lock mechanism freed it up (one owner). This was suggested to another owner whose unlock failed; the outcome isn't recorded. |
Things to check first
- Is the main battery healthy? One 2014 owner had a weak battery and blown headlight fuse at the same time as the lock-out. See Flat battery and charging system and the relays and fuses guide.
- Does the alarm respond to the fob? If the indicators flash and the dash light changes, the fob and alarm are working. That points to the locking side rather than the fob. One owner whose fob was fine still chased a bad fob for days.
- Do the fob batteries need changing? One owner replaced both and the problem remained.
- Does the steering column rocker lock and unlock? If it does but the fob doesn't, the problem is more likely the signal path from the alarm, though that is reasoning from the cases above, not a rule.
- Do the motors get power? One owner suggests checking with a multimeter at the door motors that the right wire gets power on lock and on unlock, using the workshop manual wiring diagram. The CDL module as he understands it swaps the polarity of two wires to a two-wire motor.
- Try the alarm fuse. One owner pulled the relevant fuse for a few minutes and it made no difference.
- Grease the mechanism. A stiff lock can mimic a faulty module. Graphite spray on the white plastic tabs is the owner suggestion for NAs with fitted central locking.
Both door motors failing at the same time is thought very unlikely, so owners didn't start with the doors. Replacing the CDL module is the cheapest first swap (see CDL module replacement), but a few cases above show it doesn't cure everything.
When you can't get in
- Try the key. Check whether the driver's door has a key barrel under a black disc or sticker. On many cars the key won't unlock a car locked by the fob, though it is worth a try.
- Check the backup battery. If the main battery is flat, the backup battery and the secret button let the fob work. Most backup batteries are long dead. See Central locking backup battery. One owner stuck outside with a flat battery says the button feels stiff and wondered if it had seized.
- Jump start or charge the main battery if it is flat. See Jump starting and battery chargers.
In several threads, owners who got into a locked-out car told the owner by private message and asked that it not be posted publicly. We haven't recorded those methods here. If you are stuck, ask the owners' club or a locksmith.
Help wanted
Nobody has explained the case where the switch works fully but the fob won't unlock. If you cured it, please tell us what you changed. We would also like the CDL module pinout and the alarm unit connector layout.