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Pinpoint Test L: No International Standards Organization (ISO) 9141 Network Communication, All Modules Are Not Responding

WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Module Communications Network for schematic and connector information.

Normal Operation 

The restraints control module (RCM) and the fire suppression system module (FSSM) (if equipped) communicate with the scan tool through the ISO network, circuit 70 (LB/WH).

This pinpoint test is intended to diagnose the following:

PINPOINT TEST L: NO INTERNATIONAL STANDARDS ORGANIZATION (ISO) 9141 NETWORK COMMUNICATION, ALL MODULES ARE NOT RESPONDING 

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: The supplemental restraint system (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
  1. L1 CHECK DATA LINK CONNECTOR (DLC) PINS FOR DAMAGE 
    • Key in OFF position.
    • Disconnect the scan tool cable from the DLC.
      • Fig 1: Checking DLC Pins For Damage
      GF0001408Courtesy of FORD MOTOR CO.
    • Inspect the DLC pin 7 for damage.
    • Is the DLC pin 7 OK? 
    1. YES  : Go to  L2.
    2. NO  : REPAIR the DLC as necessary. CLEAR the DTCs. REPEAT the network test with the scan tool.
  2. L2 CHECK THE ISO CIRCUIT FOR A SHORT TO VOLTAGE 
    • Deactivate the SRS. Refer to SUPPLEMENTAL RESTRAINT SYSTEM article.
    • Disconnect: RCM C310a
    • Disconnect: FSSM C3281a (if equipped)
    • Key in ON position.
    • Measure the voltage between the DLC C251-7, circuit 70 (LB/WH), harness side and ground.
    • Is any voltage present? 
    1. YES  : REPAIR the circuit. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
    2. NO  : Go to  L3.
  3. L3 CHECK THE ISO CIRCUIT FOR A SHORT TO GROUND 
    • Key in OFF position.
      • Fig 2: Checking Circuit For Short To Ground
      GF0012971Courtesy of FORD MOTOR CO.
    • Measure the resistance between the DLC C251-7, circuit 70 (LB/WH), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  L4.
    2. NO  : REPAIR the circuit. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
  4. L4 CHECK CIRCUIT 70 (LB/WH) BETWEEN THE DLC AND THE RCM FOR AN OPEN 
      Fig 3: Checking Circuit For Open
      GF0004712Courtesy of FORD MOTOR CO.
    • Measure the resistance between the RCM C310a-11, circuit 70 (LB/WH), harness side and the DLC C251-7, circuit 70 (LB/WH), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  L5.
    2. NO  : REPAIR the circuit. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
  5. L5 CHECK THE ISO CIRCUIT OPERATION WITH THE RCM CONNECTED 
    • Connect: RCM C310a
    • Key in ON position.
    • Repeat the network test with the scan tool.
    • Does the scan tool communicate with the RCM? 
    1. YES  : If the vehicle is equipped with an FSSM, go to  L6.

      If the vehicle is not equipped with an FSSM, the system is operating correctly at this time. REACTIVATE the SRS. Refer to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.

    2. NO  : Go to  L8.
  6. L6 CHECK THE ISO CIRCUIT OPERATION WITH THE FSSM CONNECTED 
    • Key in OFF position.
    • Connect: FSSM C3281a
    • Key in ON position.
    • Repeat the network test with the scan tool.
    • Does the scan tool communicate with the FSSM? 
    1. YES  : The system is operating correctly at this time. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
    2. NO  : Go to  L7.
  7. L7 CHECK FOR CORRECT FSSM OPERATION 
    • Disconnect all the FSSM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the FSSM 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 FSSM. REFER to FIRE SUPPRESSION SYSTEM article. REACTIVATE the SRS. Refer to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REACTIVATE the SRS. Refer to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
  8. L8 CHECK FOR CORRECT RCM OPERATION 
    • Disconnect all the RCM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the RCM 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 RCM. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REACTIVATE the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. CLEAR the DTCs. REPEAT the network test with the scan tool.
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