Hyundai Reviews

What you need to do is work backwards and check every connection and wiring plug that is anywhere near where you were working. A single unplugged (or even loose) sensor, connection or fitting can absolutely sideline a modern, electronically controlled engine.

You may also find you’ve damaged a sensor in the process of cleaning it (they’re pretty sensitive things) so a scan of the car may reveal that.

Also, was the cleaning process initiated by an existing problem that made you think the sensors needed cleaning? Cleaning an already dud sensor rarely brings it back to life.

This is the vehicle thinking that it’s being taken without the ignition key. In other words, stolen. The solution is to connect the negative terminal, then quickly put the key in the ignition and turn it on. This will let the car know that the key is present and there’s no threat of it being stolen.

Don’t be tempted to insert and turn the key to the on position and then connect the battery, as this could cause the battery terminal to throw a spark which is dangerous and could even send an electrical spike through the car’s computer.

You may also find that locking and unlocking with the key fob will also silence the alarm, but using the ignition key will be the quickest way to do this and minimise your neighbours’ wrath.

This is probably a case of a bad brake light switch inside the car (usually attached to the brake pedal mechanism itself). These switches can fail in the on or off position, leaving you with either no brake lights at all, or the problem you now have.

The good news is that it’s not a tough thing to fix, nor should it be expensive. The average mechanical workshop should be able to do it, and the new switch should be readily available from auto parts stores and online.