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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 2567 (Anti-Theft System - Passive Anti-Theft System (Pats)) >> Diagnostic Tests >> Anti-Theft >> Pinpoint Tests >> Pinpoint Test E: DTC B1681 - PATS Transceiver Module Signal Is Not Received

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

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Passive Anti-Theft System for schematic and connector information.

Normal Operation 

The passive anti-theft system (PATS) transceiver receives voltage from the central junction box (CJB) fuse 6 (10A) on circuit 1266 (RD/YE) and is grounded on circuit 676 (PK/OG). The PATS transceiver and the PCM communicate on circuits 1215 (WH/LG) and 1216 (GY/OG). The PCM compares the key code stored in memory with the code that was just read and enables the starter and the fuel injectors if the key code is correct.

This pinpoint test is intended to diagnose the following:

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 1266 (RD/YE) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: PATS Transceiver C252
    • Key in ON position.
      • Fig 1: Checking Circuit For Voltage
      GF0014679Courtesy of FORD MOTOR CO.
    • Measure the voltage between the PATS transceiver C252-1, circuit 1266 (RD/YE), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  E2.
    2. NO  : VERIFY the CJB fuse 6 (10A) 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 676 (PK/OG) FOR AN OPEN 
    • Key in OFF position.
      • Fig 2: Checking Circuit For Open
      GF0014680Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PATS transceiver C252-2, circuit 676 (PK/OG), 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 1216 (GY/OG) FOR VOLTAGE 
    • Connect: PATS Transceiver C252
    • Key in ON position.
      • Fig 3: Checking Circuit For Voltage
      GF0014681Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-4, circuit 1216 (GY/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 1216 (GY/OG) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: PCM C175b
    • Disconnect: PATS Transceiver C252
      • Fig 4: Checking Circuit For Short To Ground
      GF0014682Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PATS transceiver C252-4, circuit 1216 (GY/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. If DTC B1681 is retrieved again, go to  E12.
  5. E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR AN OPEN 
      Fig 5: Checking Circuit For Open
      GF0014683Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PCM C175b-42, circuit 1216 (GY/OG), harness side, and the PATS transceiver C252-4, circuit 1216 (GY/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 1215 (WH/LG) FOR VOLTAGE 
    NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the PCM again.
      Fig 6: Checking Circuit For Voltage
      GF0014685Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-3, circuit 1215 (WH/LG), 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 1215 (WH/LG) FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER CONNECTED 
    • Key in OFF position.
    • Disconnect: PCM C175b
      • Fig 7: Measuring Resistance
      GF0047694Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PCM C175b-31, circuit 1215 (WH/LG), 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 1215 (WH/LG) 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 PCM again.
    • Disconnect: PATS Transceiver C252
      • Fig 8: Measuring Resistance
      GF0047694Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PCM C175b-31, circuit 1215 (WH/LG), 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 1215 (WH/LG) FOR AN OPEN 
    • Disconnect: PATS Transceiver C252
      • Fig 9: Measuring Resistance
      GF0047695Courtesy of FORD MOTOR CO.
    • Measure the resistance between the PCM C175b-31, circuit 1215 (WH/LG), harness side and the PATS transceiver C252-3, circuit 1215 (WH/LG), 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 1215 (WH/LG) FOR VOLTAGE 
    NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the PCM again.
    • Connect: PATS Transceiver C252
    • Connect: PCM C175b
    • Connect the diagnostic tool.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: PCM DataLogger
    • Trigger the active command TRANSMIT to ON.
      • Fig 10: Checking Circuit For Voltage
      GF0014685Courtesy of FORD MOTOR CO.
    • Measure the voltage by backprobing between the PATS transceiver C252-3, circuit 1215 (WH/LG), harness side and ground.
    • Is the voltage less than 5 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.
    2. NO  : Go to  E11.
  11. E11 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: PCM C175b
    • Disconnect: PATS Transceiver C252
    • Key in ON position.
      • Fig 11: Checking Circuit For Voltage
      GF0014688Courtesy of FORD MOTOR CO.
    • Measure the voltage between the PATS transceiver C252-3, circuit 1215 (WH/LG), 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 PCM OPERATION 
    NOTE: When a new PCM is installed, the PATS keys must be programmed into the PCM.
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the PCM 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 PCM. REFER to ELECTRONIC ENGINE CONTROLS article. PROGRAM the PATS keys into the PCM. REFER to 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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