Normal Operation
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The passive anti-theft system (PATS) transceiver receives voltage from the smart junction box (SJB) fuse 5 (2A) on circuit 296 (WH/VT) and is grounded on circuit 570 (BK/WH). The PATS transceiver and the powertrain control module (PCM) communicate on circuits 167 (BN/OG) and 168 (RD/BK). The PCM compares the key code stored in memory and enables the starter if the key code is correct.
DTC B1681 - sets when the PATS transceiver signal is not received by the PCM. This diagnostic trouble code (DTC) can be caused by circuits to the PATS transceiver, circuits between the PATS transceiver and the PCM, the PATS transceiver or the PCM. This can also be caused by using the incorrect PATS transceiver part number.
Possible Causes
- Fuse
- Circuit 167 (BN/OG) open, short to ground or voltage
- Circuit 168 (RD/BK) open, short to ground
- Circuit 296 (WH/VT) open, short to ground or voltage
- Circuit 570 (BK/WH) open
- PATS key
- PATS transceiver
- PCM