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DTC B1681: Transceiver Module Signal Not Received

WARNING: This page is about a different car, the 1997 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
  1. Clear DTCs and rerun On-Demand Self-Test. See ON-DEMAND SELF-TEST in MODULE COMMUNICATIONS NETWORK article. If DTC B1681 is present, go to next step. If DTC B1681 is not present, system is operating properly.
  2. Check for proper mounting of transceiver. See TRANSCEIVER under REMOVAL & INSTALLATION  . If transceiver is mounted correctly, go to next step. If transceiver is not mounted correctly, correct condition, clear DTCs and rerun On-Demand Self-Test.
  3. Check fuse No. 15 (5-amp) in instrument panel fuse block. If fuse is okay, go to next step. If fuse is blown, go to step 8).
  4. Using scan tool, request ACTIVE COMMAND MODES PID from PATS module. Select TRANSMIT SIGNAL COMMAND ON. Transmit signal produces a 2 seconds on, 2 seconds off voltage cycle. Disconnect transceiver module connector. Module is located behind instrument cluster. Measure voltage between ground and terminalNo. 2 (Pink/Light Blue wire) at transceiver module wiring harness connector. See Figure . If voltage is more than 8 volts, go to next step. If voltage is 8 volts or less, repair open or short in circuit No. 1089 (Pink/Light Blue wire) and retest system. See WIRING DIAGRAM  .
  5. Repeat TRANSMIT SIGNAL COMMAND ON. Measure resistance between ground and terminal No. 1 (Pink/White wire) at transceiver module wiring harness connector. If resistance is less than 20 ohms, go to next step. If resistance is 20 ohms or more, repair open in circuit No. 1088 (Pink/White wire) and retest system.
  6. Repeat TRANSMIT SIGNAL COMMAND ON. Measure voltage between ground and terminal No. 4 (Dark Blue/Yellow wire) at transceiver module wiring harness connector. If voltage is more than 2 volts, go to next step. If voltage is 2 volts or less, repair open or short in circuit No. 1016 (Dark Blue/Yellow wire) and retest system.
  7. Reconnect transceiver module connector. Backprobing connector, measure voltage between ground and terminal No. 3 (Red/White wire) at transceiver module wiring harness connector. If voltage is 2 volts or less, repair open or short in circuit No. 1015 (Red/White wire) and retest system. If voltage is more than 2 volts, replace PATS transceiver module. Clear DTCs and rerun On-Demand Self-Test. If DTC B1681 is still present, replace PATS module. Clear DTCs and retest system.
  8. Replace fuse No. 15. Turn ignition to RUN position. Recheck fuse No. 15. If fuse is okay, system is operating properly. Clear DTCs and rerun On-Demand Self-Test. If fuse is blown, go to next step.
  9. Turn ignition off. Disconnect PATS module 16-pin connector. PATS module is located behind center of instrument panel. Disconnect Generic Electronic Module (GEM) 18-pin connector. GEM is mounted to instrument panel fuse block. Measure resistance between ground and terminal No. 15 (White/Yellow wire) at PATS module connector. See Fig 1 . If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short to ground in circuit No. 1001 (White/Yellow wire). Clear DTCs and retest system.
  10. Reconnect PATS module connector. Replace fuse No. 15. Turn ignition to RUN position. Recheck fuse. If fuse is okay, replace GEM. Clear DTCs and retest system. If fuse is blown, replace PATS module. Clear DTCs and retest system.
Fig 1: Identifying PATS Module Connector Terminals
G95C34928Courtesy of FORD MOTOR CO.
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