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Pinpoint Test E: DTC B1681 - Pats Transceiver Module Signal Is Not Received

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. E1 CHECK THE PATS TRANSCEIVER POWER CIRCUIT CBP36 (BU/BN) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: PATS Transceiver C252
    • Key in ON position.
      • Fig 1: Measuring Voltage Between PATS Transceiver C252-1, Circuit CBP36 (BU/BN) & Ground
      GF0014679Courtesy of FORD MOTOR CO.
    • Measure the voltage between the PATS transceiver C252-1, circuit CBP36 (BU/BN), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  E2.
    2. NO  : VERIFY the smart junction box (SJB) fuse 36 (5A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  2. E2 CHECK THE PATS TRANSCEIVER GROUND CIRCUIT GD115 (BK/GY) FOR AN OPEN 
    • Key in OFF position.
      • Fig 2: Measuring Resistance Between PATS Transceiver C252-2, Circuit GD115 (BK/GY) & Ground
      GF0014680Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PATS transceiver C252-2, circuit GD115 (BK/GY), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  E3.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  3. E3 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT VRT24 (YE/OG) FOR VOLTAGE 
    • Connect: PATS Transceiver C252
    • Key in ON position.
      • Fig 3: Measuring Voltage By Backprobing Between PATS Transceiver C252-4, Circuit VRT24 (YE/OG)
      GF0014681Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side and ground.
    • Is the voltage greater than 8 volts? 
    1. YES  : Go to  E6.
    2. NO  : Go to  E4.
  4. E4 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT VRT24 (YE/OG) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: IC C220
    • Disconnect: PATS Transceiver C252
      • Fig 4: Measuring Resistance Between PATS Transceiver C252-4, Circuit VRT24 (YE/OG) & Ground
      GF0014682Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  E5.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  5. E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT VRT24 (YE/OG) FOR AN OPEN 
      Fig 5: Measuring Resistance Between IC C220-3, Circuit VRT24 (YE/OG) & PATS Transceiver C252-4
      GF0030585Courtesy of FORD MOTOR CO.
    • Measure the resistance between the IC C220-3, circuit VRT24 (YE/OG), harness side and the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  E12.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  6. E6 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR VOLTAGE 
    NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.
      Fig 6: Measuring Voltage By Backprobing Between PATS Transceiver C252-3, Circuit VRT23 (VT/GY)
      GF0014685Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.
    • Is the voltage greater than 8 volts? 
    1. YES  : INSTALL a new PATS transceiver. REFER to Passive Anti-Theft System (PATS) Transceiver . CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

      If DTC B1681 is retrieved again, go to  E12.

    2. NO  : Go to  E7.
  7. E7 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER CONNECTED 
    • Key in OFF position.
    • Disconnect: IC C220
      • Fig 7: Measuring Resistance Between IC C220-4, Circuit VRT23 (VT/GY), Harness Side & Ground
      GF0032362Courtesy of FORD MOTOR CO.
    • Measure the resistance between the IC C220-4, circuit VRT23 (VT/GY), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  E9.
    2. NO  : Go to  E8.
  8. E8 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER DISCONNECTED 
    NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.
    • Disconnect: PATS Transceiver C252
      • Fig 8: Measuring Resistance Between IC C220-4, Circuit VRT23 (VT/GY), Harness Side & Ground
      GF0032362Courtesy of FORD MOTOR CO.
    • Measure the resistance between the IC C220-4, circuit VRT23 (VT/GY), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : INSTALL a new PATS transceiver. REFER to Passive Anti-Theft System (PATS) Transceiver . CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  9. E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR AN OPEN 
    • Disconnect: PATS Transceiver C252
      • Fig 9: Measuring Resistance Between IC C220-4, Circuit VRT23 (VT/GY) & PATS Transceiver C252-3
      GF0030583Courtesy of FORD MOTOR CO.
    • Measure the resistance between the IC C220-4, circuit VRT23 (VT/GY), harness side and the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  E10.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  10. E10 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR VOLTAGE 
    NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.
    • Connect: PATS Transceiver C252
    • Connect: IC C220
    • Connect the diagnostic tool.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: IC Active Commands
    • Trigger the IC active command Transmit Signal to on.
      • Fig 10: Measuring Voltage By Backprobing Between PATS Transceiver C252-3, Circuit VRT23 (VT/GY)
      GF0014685Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.
    • Is the voltage less than 5 volts? 
    1. YES  : INSTALL a new PATS transceiver module. REFER to Passive Anti-Theft System (PATS) Transceiver . CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
    2. NO  : Go to  E11.
  11. E11 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT VRT23 (VT/GY) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: IC C220
    • Disconnect: PATS Transceiver C252
    • Key in ON position.
      • Fig 11: Measuring Voltage Between PATS Transceiver C252-3, Circuit VRT23 (VT/GY) & Ground
      GF0014688Courtesy of FORD MOTOR CO.
    • Measure the voltage between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.
    • Is any voltage indicated? 
    1. YES  : REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
    2. NO  : Go to  E12.
  12. E12 CHECK FOR CORRECT IC OPERATION 
    NOTE: When a new IC is installed, the PATS keys must be programmed into the new IC.
    NOTE: When a new IC is installed, the parameters must be reset in the IC and the PCM.
    • Disconnect all the IC connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the IC connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new IC. REFER to INSTRUMENT CLUSTER . RESET the parameters in both the IC and the PCM. REFER to Passive Anti-Theft System (PATS) Parameter Reset . PROGRAM the PATS keys into the new IC. REFER to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment . REPEAT the self-test.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
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