LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 1997 >> Contour Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 76 (Anti-Theft Systems - Passive) >> Diagnostic Trouble Code Tests >> DTC B1681: Transceiver Module Signal Not Received
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC B1681: Transceiver Module Signal Not Received

WARNING: This page is about a different car, the 1998 Mercury Mountaineer and 1998 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Retrieve DTCs  Turn ignition off. Using NGS tester, retrieve and document continuous DTCs. Clear continuous DTCs and perform PATS On-Demand Self-Test. If DTC B1681 is retrieved, go to next step. If DTC B1681 is not retrieved, system is operating properly.
  2. Check For Voltage To Transceiver Module  Turn ignition off. Disconnect transceiver module 4-pin connector C221 (located at bottom right side of steering column). Turn ignition to RUN position. Using a voltmeter, check voltage between ground and transceiver module 4-pin connector C221 terminal No. 2 (Dark Green/White wire). See Fig 1 . If voltage is more than 9 volts, go to next step. If voltage is 9 volts or less, repair Dark Green/White wire between transceiver module and PATS module. Clear DTCs and retest system operation.
  3. Check Transceiver Module Ground Circuit  Turn ignition off. Using an ohmmeter, check resistance between ground and transceiver module 4-pin connector C221 terminal No. 1 (Black/Yellow wire). See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair Black/Yellow wire between transceiver module and PATS module. Clear DTCs and retest system operation.
  4. Check Gray/Orange Wire For Voltage (Transceiver Module Connected)  Turn ignition off. Connect transceiver module 4-pin connector C221. Turn ignition to RUN position. Using a voltmeter, check voltage by backprobing between transceiver module 4-pin connector C221 terminal No. 3 (Gray/Orange wire) and ground. See Fig 1 . If voltage is 9 volts or less, go to next step. If voltage is more than 9 volts, go to step 6).
  5. Check Gray/Orange Wire For Short  Turn ignition off. Disconnect transceiver module 4-pin connector C221 (located at bottom right side of steering column). Using an ohmmeter, check resistance between ground and transceiver module 4-pin connector C221 terminal No. 3 (Gray/Orange wire). See Fig 1 . If resistance is more than 100 ohms, go to next step. If resist ance is 100 ohms or less, check Gray/Orange wire for short to ground. Repair circuit as necessary. Clear DTCs and retest system operation. If wire is okay, replace PATS module. Clear DTCs and retest system operation.
  6. Check White/Light Green Wire For Voltage  Turn ignition off. Connect transceiver module 4-pin connector C221. Turn ignition to RUN position. Using a voltmeter, check voltage by backprobing between transceiver module 4-pin connector C221 terminal No. 4 (White/Light Green wire) and ground. See Fig 1 . If voltage is 9 volts or less, go to next step. If voltage is more than 9 volts, go to step 8).
  7. Check White/Light Green Wire For Short  Turn ignition off. Disconnect transceiver module 4-pin connector C221 (located at bottom right side of steering column). Using an ohmmeter, check resistance between ground and transceiver module 4-pin connector C221 terminal No. 4 (White/Light Green wire). See Fig 1 . If resistance is more than 100 ohms, go to next step. If resistance is 100 ohms or less, check White/Light Green wire for short to ground. Repair circuit as necessary. Clear DTCs and retest system operation. If wire is okay, replace PATS module. Clear DTCs and retest system operation.
  8. Check White/Light Green Wire For Proper Operation  Turn ignition off. Connect transceiver module 4-pin connector C221. Turn ignition to RUN position. Using NGS tester, trigger PATS active command TRANSMIT SIGNAL COMMAND to ON. Using a voltmeter, check voltage by backprobing between transceiver module 4-pin connector C221 terminal No. 4 (White/Light Green wire) and ground while triggering active command on. If voltage drops from more than 9 volts to less than one volt when active command is triggered on, go to next step. If voltage does not drop from more than 9 volts to less than one volt when active command is triggered on, check White/Light Green wire between transceiver module and PATS module. Repair circuit as necessary. Clear DTCs and retest system operation. If wire is okay, replace PATS module. Clear DTCs and retest system operation.
  9. Replace PATS Transceiver Module  Turn ignition off. Replace PATS transceiver module. See TRANSCEIVER MODULE  under REMOVAL & INSTALLATION. Using customers original encoded ignition key, turn ignition to RUN position. Perform PATS On-Demand Self-Test. If DTC B1681 is retrieved, go to next step. If DTC B1681 is not retrieved, system is operating properly.
  10. Replace PATS Module  Turn ignition off. Replace PATS module. See PATS MODULE  under REMOVAL & INSTALLATION. Using customers original encoded ignition key, turn ignition to RUN position. Perform PATS On-Demand Self-Test. If DTC B1681 is retrieved, check circuits between PATS module and transceiver module. See WIRING DIAGRAMS  . Repair circuits as necessary. Clear DTCs and retest system operation. If no DTCs are retrieved, system is operating properly. If any DTCs are retrieved, perform appropriate DTC test for trouble code retrieved.
Fig 1: Identifying Transceiver Module Connector C221 Terminals
G97J28810Courtesy of FORD MOTOR CO.
scientia non olet · About LEMON Manuals