Pinpoint Test C: The RCM Does Not Respond To The Scan Tool

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

WARNING: Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.

WARNING: Never probe the electrical connectors on air bag, Safety Canopy® or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

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.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to BATTERY, MOUNTING AND CABLES .

C1 CHECK THE RCM CONNECTION
- Ignition OFF.
- Depower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Disconnect: RCM C310a.
- Disconnect: RCM C310b.
- Are RCM C310a pin 12 and RCM C310b pins 17 and 18 OK?
- Yes: GO to C2 .
- No: REPAIR the RCM connector pins as necessary. REPOWER the SRS REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING CLEAR the DTCs. REPEAT the network test with the scan tool.
C2 CHECK THE RCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Deactivate the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING
- Repower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Ignition ON.
- Measure the voltage between the RCM C310a-12, circuit CBP46 (WH/BU), harness side and ground.
  
  Fig 1: Measuring Voltage Between RCM C310A-12, Circuit CBP46 (WH/BU) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to C3 .
- No: VERIFY the Smart Junction Box (SJB) fuse 46 (7.5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS for Edge or SYSTEM WIRING DIAGRAMS for MKX to identify the possible causes of the circuit short. REACTIVATE the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . CLEAR the DTCs. REPEAT the network test with the scan tool.
C3 CHECK THE RCM CASE GROUND
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the RCM case and a good chassis ground.
- Is the resistance less than 5 ohms?
- Yes: GO to C4 .
- No: REPAIR the RCM case ground as necessary. CONNECT the negative battery cable. REACTIVATE the SRS REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING CLEAR the DTCs. REPEAT the network test with the scan tool.
C4 CHECK THE HS-CAN CIRCUITS BETWEEN THE RCM AND THE DLC FOR AN OPEN
- Measure the resistance between the RCM C310b-18, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
  
  Fig 2: Measuring Resistance Between RCM C310B-18, Circuit VDB04 (WH/BU) And DLC C251-6, Circuit VDB04 (WH/BU)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the RCM C310b-17, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
  
  Fig 3: Measuring Resistance Between RCM C310b-17, Circuit VDB05 (WH) And DLC C251-14, Circuit VDB05 (WH)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: CONNECT the negative battery cable. GO to C5 .
- No: REPAIR the circuit in question. CONNECT the negative battery cable. REACTIVATE the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . CLEAR the DTCs. REPEAT the network test with the scan tool.
C5 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?
- Yes: INSTALL a new RCM . REACTIVATE the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING CLEAR the DTCs. REPEAT the network test with the scan tool.
- 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 (SRS) DEPOWERING AND REPOWERING CLEAR the DTCs. REPEAT the network test with the scan tool.