Diagnostics Doctor

My daughter has a Ford Fiesta Zetec 1398cc petrol registered in 2008. It is low mileage and has been very well looked-after. The minor problem is that the driver’s door takes three remote blips before it unlocks; the other doors unlock after the first blip. All the doors will unlock immediately if the key is used directly in the driver’s door lock.

I renewed the driver’s door latch assembly, but it didn’t help, so I assume it’s a programming issue. The vehicle’s handbook is unhelpful on this matter, but I’ve read various posts on the internet which recommend unlocking the driver’s door then simultaneously holding down the lock and unlock buttons on the remote, but this didn’t work.

I have access to a Ford VCM II diagnostic interface and this doesn’t appear to highlight a fault, although it did show ‘DTC B1175’ and ‘Failure type 92 (protocol 14229)’, but I think this was because the driver’s door was open while the test was being run. Bruce When you replaced the latch assembly, did this include the solenoid/motor and locking cable? Yes, I replaced the whole assembly. Bruce It has to be a wiring problem. As all four other doors get triggered off the same circuit, the fault must be in the wiring between the latch assembly and the wiring loom under the dash – probably in the section running from the door to the inner wing, where constant movement over the years can cause wires to part company. You could confirm this by installing temporary wiring that bypasses that point or by taking a bypass feed from another door. The wiring appears to be intact. I tested continuity while moving the wiring loom between the door and frame. Bruce In that case it looks like the multifunction control module is at fault, though the wiring diagram I am referring to could be the wrong one. Is your car model pre-2008 or later, with a singleor double-locking system? The car is a 2008 onwards model, but I’m not sure if it’s single- or double-locking. How can I tell? Bruce I assumed it was a 2008+ single-locking model. You can tell the difference by locking the car from the outside with a window left open. If you can then reach through the window and unlock the door from the inside, it is single-locking. To recap: I’ve changed the door lock/ latch mechanism and the door wiring loom to no avail. I guess the next stage is to change the central-locking module, but my daughter baulks at paying £80 with no guarantee it will work. At the moment, she seems happy to continue to use the key in the door lock. Bruce