B1601: PATS Received Bad Key-Code From Transponder

B1601-1 - B1601-6:

NOTE:
- Large metallic objects or devices such as the Mobil Speedpass or a second ignition key on the same key ring as the PATS ignition key may cause vehicle starting problems and this DTC under certain conditions. If a fault cannot be identified, examine the customer's key ring for such objects or devices. If present, inform the customer that they need to keep these objects from touching the PATS ignition key while starting the engine.
- These objects and devices cannot damage the PATS ignition key, but can cause a momentary problem if they are too close to the key during engine start. If a problem occurs, turn ignition off and restart the engine while all other objects on the key ring held away from the ignition key. Check to ensure the encoded ignition key used by the customer is an approved Ford encoded ignition key (encoded ignition keys from Rotunda, IIco, Curtis, or Strattec are approved encoded ignition keys).