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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1505 (Anti-Theft System - Passive Anti-Theft System (Pats) - (Except Hybrid)) >> Diagnosis And Testing >> Anti-Theft >> Pinpoint Tests >> Pinpoint Test E: DTC B1681 >> Pinpoint Test E: DTC B1681

Pinpoint Test E: DTC B1681

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery will result in false resistance readings. Refer to BATTERY DISCONNECT .
  1. E1 CHECK THE PATS TRANSCEIVER POWER CIRCUIT FOR VOLTAGE 
    • Ignition OFF.
    • Disconnect: PATS  Transceiver C252.
    • Ignition ON.
    • Measure the voltage between the PATS  transceiver C252-1, circuit CBP36 (BU/BN), harness side and ground.
      Fig 1: Measuring Voltage Between PATS Transceiver C252-1, Circuit CBP36 (BU/BN), Harness Side And Ground
      G06099447Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  GO to E2  .
    • No:  VERIFY the SJB  fuse 36 (5A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
  2. E2 CHECK THE PATS TRANSCEIVER GROUND CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Disconnect: Negative Battery Cable.
    • Measure the resistance between the PATS  transceiver C252-2, circuit GD112 (BK/GN), harness side and ground.
      Fig 2: Measuring Resistance Between PATS Transceiver C52-2, Circuit GD112 (BK/GN), Harness Side And Ground
      G06099448Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  CONNECT the negative battery cable. GO to E3  .
    • No:  REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.
  3. E3 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR VOLTAGE 
    NOTE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list in this article. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while ensuring that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.
    • Connect: PATS  Transceiver C252.
    • Ignition ON.
    • Measure the voltage by back-probing between the PATS  transceiver C252-4, circuit VRT23 (VT/GY), harness side and ground.
      Fig 3: Measuring Voltage By Back-Probing Between PATS Transceiver C252-4, Circuit VRT23 (VT/GY), Harness Side And Ground
      G06099449Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 8 volts? 
    • Yes:  GO to  E6.
    • No:  GO to E4  .
  4. E4 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR A SHORT TO GROUND 
    • Ignition OFF.
    • Disconnect: IC  C220.
    • Disconnect: PATS  Transceiver C252.
    • Measure the resistance between the PATS  transceiver C252-4, circuit VRT23 (VT/GY), harness side and ground.
      Fig 4: Measuring Resistance Between PATS Transceiver C252-4, Circuit VRT23 (VT/GY), Harness Side And Ground
      G06099450Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes:  GO to E5  .
    • No:  REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.

      If DTC B1681 is retrieved again, GO to  E12.

  5. E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR AN OPEN 
    • Measure the resistance between the IC  C220-3, circuit VRT23 (VT/GY), harness side and the PATS  transceiver C252-4, circuit VRT23 (VT/GY), harness side.
      Fig 5: Checking PATS Transceiver Receive Circuit For An Open
      G06391102Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 volts? 
    • Yes:  GO to  E12.
    • No:  REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.
  6. E6 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR VOLTAGE 
    NOTE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list in this article. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while ensuring that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.
    NOTE: Replacement of the PATS  transceiver does not require the PATS  keys to be programmed into the IC  again.
    • Measure the voltage by back-probing between the PATS  transceiver C252-3, circuit VRT24 (YE/OG), harness side and ground.
      Fig 6: Measuring Voltage By Back-Probing Between PATS Transceiver C252-3, Circuit VRT24 (YE/OG), Harness Side And Ground
      G06099452Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 8 volts? 
    • Yes:  INSTALL a new PATS  transceiver. REFER to PASSIVE ANTI-THEFT SYSTEM (PATS) TRANSCEIVER . CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.

      If DTC B1681 is retrieved again, GO to  E12.

    • No:  GO to E7  .
  7. E7 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER CONNECTED 
    • Ignition OFF.
    • Disconnect: IC  C220.
    • Measure the resistance between the IC  C220-4, circuit VRT24 (YE/OG), harness side and ground.
      Fig 7: Measuring Resistance Between IC C220-4, Circuit VRT24 (YE/OG), Harness Side And Ground
      G06391104Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes:  GO to  E9.
    • No:  GO to E8  .
  8. E8 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 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.
    • Measure the resistance between the IC  C220-4, circuit VRT24 (YE/OG), harness side and ground.
      Fig 8: Measuring Resistance Between IC C220-4, Circuit VRT24 (YE/OG), Harness Side And Ground
      G06391104Courtesy 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. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.
    • No:  REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.
  9. E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR AN OPEN 
    • Disconnect: PATS  Transceiver C252.
    • Measure the resistance between the IC  C220-4, circuit VRT24 (YE/OG), harness side and the PATS  transceiver C252-3, circuit VRT24 (YE/OG), harness side.
      Fig 9: Checking PATS Transceiver Transmit Circuit For An Open
      G06391106Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to E10  .
    • No:  REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.
  10. E10 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR VOLTAGE 
    NOTE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list in this article. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while ensuring that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.
    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 scan tool.
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: IC  DataLogger.
    • Trigger the IC  active command TRANSMIT SIGNAL to on.
      • NOTE: The voltage only reads for a very short period of time. Make sure to monitor the meter closely while triggering the active command on.
    • Measure the voltage by back-probing between the PATS  transceiver C252-3, circuit VRT24 (YE/OG), harness side and ground.
      Fig 10: Measuring Voltage By Back-Probing Between PATS Transceiver C252-3, Circuit VRT24 (YE/OG), Harness Side And Ground
      G06099452Courtesy of FORD MOTOR CO.
    • Is the voltage less than 5 volts? 
  11. E11 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition OFF.
    • Disconnect: IC  C220.
    • Disconnect: PATS  Transceiver C252.
    • Ignition ON.
    • Measure the voltage between the PATS  transceiver C252-3, circuit VRT24 (YE/OG), harness side and ground.
      Fig 11: Measuring Voltage Between PATS Transceiver C252-3, Circuit VRT24 (YE/OG), Harness Side And Ground
      G06099457Courtesy of FORD MOTOR CO.
    • Is any voltage indicated? 
    • Yes:  REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.
    • No:  GO to E12  .
  12. E12 CHECK FOR CORRECT IC OPERATION 
    • Disconnect the IC  connector.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect the IC  connector and make sure it seats correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
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