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Home >> Mercury >> 2010 >> Milan Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 177 (Supplemental Inflatable Restraint System) >> Diagnosis And Testing >> Pinpoint Tests - Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Test A: The Air Bag Warning Indicator Is Illuminated Continuously - RCM Disconnected or Inoperative, Loss of Battery Feed, or Loss of Signal Ground >> Testing

Pinpoint Test A: The Air Bag Warning Indicator Is Illuminated Continuously - RCM Disconnected or Inoperative, Loss of Battery Feed, or Loss of Signal Ground: Testing

WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
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. A1 CHECK FOR CONTINUOUS OR ON-DEMAND DTCs 
    WARNING: Restraint system diagnostic tools are for service only. Tools must be removed prior to operating the vehicle over the road. Failure to remove restraint system diagnostic tools could result in injury and possible violation of vehicle safety standards.
    WARNING: Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow these instructions may result in the inadvertent deployment of the safety canopy and risk of personal injury.
    WARNING: Never probe the connectors on the air bag module. Doing so can result in air bag deployment, which can result in personal injury.
    WARNING: The safety belt pretensioner is a pyrotechnic device. Always wear safety glasses when repairing an air bag equipped vehicle and when handling a safety belt buckle pretensioner or safety belt retractor pretensioner. Never probe a pretensioner electrical connector. Doing so could result in pretensioner or air bag deployment and could result in personal injury.
    WARNING: Never probe the electrical connector on a safety canopy module. Doing so can result in safety canopy deployment.
    NOTE: If a seat equipped with a supplemental restraint system (SRS) component is being serviced, the SRS must be depowered.
    NOTE: After diagnosing or repairing an SRS, the restraint system diagnostic tools must be removed before operating the vehicle over the road. 
    NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
    • Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
    • Enter the following diagnostic mode on the scan tool: Retrieve/Record Continuous DTCs.
    • Were any continuous or on-demand self test DTCs retrieved? 
    1. Yes  : If continuous DTCs were retrieved, GO to A2. If on-demand DTCs were retrieved, GO to the RESTRAINTS CONTROL MODULE (RCM) DIAGNOSTIC TROUBLE CODE (DTC) TABLE  for pinpoint test direction.
    2. No  : GO to A2.
  2. A2 CHECK THE RCM CONNECTION 
    1. Yes  : GO to A3.
    2. No  : CONNECT C310a and ENGAGE the locking tab. GO to  A7.
  3. A3 CHECK CIRCUIT 937 (RD/WH) FOR AN OPEN 
    • Deactivate the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEACTIVATION AND REACTIVATION .
    • Disconnect: RCM C310a and C310b.
    • Key in ON position.
    • Measure the voltage between RCM C310a pin 12, circuit 937 (RD/WH), harness side and ground.
      Fig 1: Measuring Voltage Between RCM Connector And Ground
      G03881123Courtesy of FORD MOTOR CO.
    • Is the voltage between 8 and 18 volts 
    1. Yes  : GO to A4.
    2. No  : REPAIR circuit 937 (RD/WH). GO to  A7.
  4. A4 CHECK THE RCM CASE GROUND 
    • Key in OFF position.
    • Measure the resistance between the RCM case and a good chassis ground.
    • Is the resistance less than 5 ohms? 
    1. Yes  : GO to A5.
    2. No  : REPAIR RCM case ground as necessary. GO to  A7.
  5. A5 CHECK HS-CAN CIRCUITS BETWEEN THE RCM AND THE INSTRUMENT CLUSTER MODULE FOR AN OPEN 
    • Disconnect: Instrument Cluster Module C220.
    • Measure the resistance between RCM C310b pin 31, circuit 1908 (WH), harness side and instrument cluster module C220 pin 18, circuit 1908 (WH), harness side; and between RCM C310b pin 32, circuit 1909 (BK), harness side and instrument cluster module C220 pin 19, circuit 1909 (BK), harness side.
      Fig 2: Checking HS-CAN Circuits Between RCM And Instrument Cluster Module For Open
      G03989423Courtesy of FORD MOTOR CO.
    • Are the resistances less than 0.5 ohm? 
    1. Yes  : GO to A6.
    2. No  : REPAIR circuit 1908 (WH), or circuit 1909 (BK). GO to  A7.
  6. A6 CHECK THE RCM 
    • Connect: Instrument Cluster Module C220.
    • Connect: RCM C310a and C310b.
    • Enter the following diagnostic mode on the scan tool: Instrument Cluster Module Active Command - Warning Lamps.
    • Does the air bag warning indicator turn on and off when using the active command? 
    1. Yes  : INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to A7.
    2. No  : INSTALL a new instrument cluster module. REFER to INSTRUMENT CLUSTER . GO to A7.
  7. A7 CHECK FOR ADDITIONAL DTCs 
    • Refer to the continuous DTCs recorded during Step  A1.
    • Were any continuous DTCs retrieved during Step   A1 ? 
    1. Yes  : Do not clear any DTCs until all DTCs have been resolved. GO to the RESTRAINTS CONTROL MODULE (RCM) DIAGNOSTIC TROUBLE CODE (DTC) TABLE  for pinpoint test direction.
    2. No  : RECONNECT the system. If previously directed to deactivate the system, REACTIVATE the system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEACTIVATION AND REACTIVATION . REPOWER the system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . PROVE OUT the system. CLEAR all DTCs.
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