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Pinpoint Test E: DTC B1684 - Pats Transceiver Module Signal Is Not Received

WARNING: This page is about a different car, the 2006 Mercury Montego, 2006 Ford Freestyle, and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.
  1. E1 RETRIEVE THE DIAGNOSTIC TROUBLE CODES (DTCS) 
    • Enter the following diagnostic mode on the diagnostic tool: Clear the DTCs.
    • Key in OFF position.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Retrieve the DTCs.
    • Is DTC B1681 retrieved? 

    Yes:  GO to  E2.

    No:  The system is OK.

  2. E2 CHECK THE PATS TRANSCEIVER CIRCUIT 1266 (RD/YE) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: PATS Transceiver C252.
    • Key in ON position.
    • Measure the voltage between the PATS transceiver C252-1, circuit 1266 (RD/YE), harness side and ground.
    Fig 1: Measuring Voltage Between PATS Transceiver C252-1, Circuit 1266 (RD/YE), Harness Side & Ground
    G04658434Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 

    Yes:  GO to  E3.

    No:  VERIFY the smart junction box (SJB) fuse 18 (10A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

  3. E3 CHECK THE PATS TRANSCEIVER GROUND CIRCUIT 1203 (BK/LB) 
    • Key in OFF position.
    • Measure the resistance between the PATS transceiver C252-2, circuit 1203 (BK/LB), harness side and ground.
    Fig 2: Measuring Resistance Between PATS Transceiver C252-2, Circuit 1203 (BK/LB), Harness Side & Ground
    G04658435Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 

    Yes:  GO to  4.

    No:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

  4. E4 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR VOLTAGE 
    • Connect: PATS Transceiver C252.
    • Key in ON position.
    • Measure the voltage by back probing between the PATS transceiver C252-4, circuit 1216 (GY/OG), harness side and ground.
    Fig 3: Measuring Voltage By Back Probing Between PATS Transceiver C252-4, Circuit 1216 (GY/OG), Harness Side & Ground
    G04658436Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 9 volts? 

    Yes:  GO to  E6.

    No:  GO to  E5.

  5. E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: PATS Transceiver C252.
    • Measure the resistance between the PATS transceiver C252-4, circuit 1216 (GY/OG), harness side and ground.
    Fig 4: Measuring Resistance Between PATS Transceiver C252-4, Circuit 1216 (GY/OG), Harness Side & Ground
    G04658437Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 

    Yes:  GO to  E6.

    No:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. If the system fails again, GO to  E13.

  6. E6 CHECK CIRCUIT 1216 (GY/OG) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: PATS Transceiver C252.
    • Disconnect: PCM C175b.
    • Measure the resistance between the PATS transceiver C252-4, circuit 1216 (GY/OG), harness side and the PCM C175b-42, circuit 1216 (GY/OG), harness side.
    Fig 5: Measuring Resistance Between PATS Transceiver C252-4, Circuit 1216 (GY/OG), Harness Side & PCM C175b-42, Circuit 1216 (GY/OG) & Harness Side
    G04658438Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 

    Yes:  GO to  7.

    No:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

  7. E7 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR VOLTAGE 
    • Key in OFF position.
    • Connect: PATS Transceiver C252.
    • Connect: PCM C175b.
    • Key in ON position.
    • Measure the voltage by back-probing between the PATS transceiver C252-C, circuit 1215 (WH/LG), harness side and ground.
    Fig 6: Measuring Voltage By Back-Probing Between PATS Transceiver C252-C, Circuit 1215 (WH/LG), Harness Side & Ground
    G04658439Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 9 volts? 

    Yes:  GO to  E11.

    No:  GO to  E8.

  8. E8 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO GROUND IN CIRCUIT 1215 (WH/LG) WITH THE TRANSCEIVER CONNECTED 
    • Key in OFF position.
    • Disconnect: PCM C175b.
    • Measure the resistance between the PCM C175b-22, circuit 1215 (WH/LG), harness side and ground.
    Fig 7: Checking PATS Transceiver Transmit Circuit For Short To Ground In Circuit 1215 (WH/LG) With Transceiver Connected
    G04658440Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 

    Yes:   GO to  E10.

    No:   GO to  E9.

  9. E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO GROUND IN CIRCUIT 1215 (WH/LG) WITH THE TRANSCEIVER DISCONNECTED 
    • Disconnect: PATS Transceiver C252.
    • Measure the resistance between the PATS transceiver C252-3, circuit 1215 (WH/LG), harness side and ground.
    Fig 8: Measuring Resistance Between PATS Transceiver C252-3, Circuit 1215 (WH/LG), Harness Side & Ground
    G04658441Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 

    Yes:  INSTALL a new PATS transceiver. refer to PASSIVE ANTI-THEFT SYSTEM (PATS) TRANSCEIVER . CLEAR the DTCs. REPEAT the self-test.

    No:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

  10. E10 CHECK THE PATS TRANSMIT CIRCUIT 1215 (WH/LG) FOR AN OPEN 
    • Disconnect: PATS Transceiver C252.
    • Measure the resistance between the PATS transceiver C252-3, circuit 1215 (WH/LG), harness side and the PCM C175b-22, circuit 1215 (WH/LG), harness side.
    Fig 9: Measuring Resistance Between PATS Transceiver C252-3, Circuit 1215 (WH/LG), Harness Side & PCM C175b-22, Circuit 1215 (WH/LG), Harness Side
    G04658442Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 

    Yes:  GO to  E13.

    No:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

  11. E11 CHECK THE TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR VOLTAGE 
    • Key in ON position.
    • Use the diagnostic tool to access the active command TRANSMIT SIGNAL COMMAND.
    • Enter the following diagnostic mode on the diagnostic tool: Trigger TRANSMIT to ON.
    • Measure the voltage by back-probing between the PATS transceiver C252-3, circuit 1215 (WH/LG), harness side and ground.
    • Is the voltage less than 5 volts? 
      • Fig 10: Measuring Voltage By Back-Probing Between PATS Transceiver C252-3, Circuit 1215 (WH/LG), Harness Side & Ground
      G04658443Courtesy of FORD MOTOR CO.

    Yes:  INSTALL a new PATS transceiver. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) TRANSCEIVER . CLEAR the DTCs. REPEAT the self-test.

    No:  GO to  E12.

  12. E12 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO BATTERY 
    • Key in OFF position.
    • Disconnect: PCM C175b.
    • Disconnect: PATS Transceiver C252.
    • Key in ON position.
    • Measure the voltage between the PATS C252-3, circuit 1215 (WH/LG), harness side and ground.
    Fig 11: Measuring Voltage Between PATS C252-3, Circuit 1215 (WH/LG), Harness Side & Ground
    G04658444Courtesy of FORD MOTOR CO.
    • Is any voltage present? 

    Yes:  REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

    No:  GO to  E13.

  13. E13 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all of the PCM connectors.
    • Check for:
    • corrosion
    • pushed-out pins
    • Connect all of the PCM connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 

    Yes:  INSTALL a new PCM. Refer to INSTALLATION . PROGRAM the encoded keys. REFER to KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT . TEST the system for normal operation.

    No:  The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

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