Question

how do I fix the p1685 code on my Jeep Liberty CRD?

Answer 1

Someone probably try to start the engine with the wrong or defective key.

Here are the possible cause for this problem:

1. Theft attempt
2. Wrong key attempted in the ignition lock cylinder
3. Ignition lock cylinder defective

Try disconnecting the battery for about 30 minutes and then try restarting the vehicle with a known good key.