Pinpoint Test X: No Communication With The Restraints Control Module RCM

WARNING: This page is about a different car, the 2005 Ford Pickup. 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.

X1 CHECK THE RCM C310a PIN 11 FOR DAMAGE
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: 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.

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.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Disconnect: RCM C310a and C310b.
- Inspect the RCM C310a, harness side and RCM C310a, component side, pin 11 for damage.
- Are RCM C310a and RCM C310a pin 11 OK?
- Yes : GO to X2.
- No : REPAIR RCM C310a or RCM C310a pin 11 as necessary. RETEST the communication to the RCM. 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.
X2 CHECK THE DLC C251 PIN 7 FOR DAMAGE
- Inspect the DLC C251 and DLC C251 pin 7 for damage.
  
  Fig 1: Locating DLC Pin 7
  Courtesy of FORD MOTOR CO.
- Are DLC C251 and DLC C251 pin 7 OK?
- Yes : GO to X3.
- No : REPAIR DLC C251 or DLC C251 pin 7 as necessary. RETEST the communication to the RCM. 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.
X3 CHECK THE IGNITION CIRCUIT 937 (RD/WH) FOR AN OPEN
- Deactivate the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEACTIVATION AND REACTIVATION .
- Key in ON position.
- Measure the voltage between RCM C310a pin 12, circuit 937 (RD/WH), harness side and ground.
  
  Fig 2: Measuring Voltage Between RCM Connector And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to X4.
- No : REPAIR circuit 937 (RD/WH). RETEST the communication to the RCM. 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.
X4 CHECK THE GROUND CIRCUIT 1203 (BK/LB) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between RCM C310a pin 16, circuit 1203 (BK/LB), harness side and a sheet metal ground near the RCM.
  
  Fig 3: Measuring Resistance Between RCM C310a Pin 16, Circuit 1203 (BK/LB), Harness Side And Sheet Metal Ground Near RCM
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to X5.
- No : REPAIR circuit 1203 (BK/LB). RETEST the communication to the RCM. 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.
X5 CHECK CIRCUIT 70 (LB/WH) FOR A SHORT TO VOLTAGE
- Key in ON position.
- Measure the voltage between DLC C251 pin 7, circuit 70 (LB/WH), harness side and ground.
  
  Fig 4: Measuring Voltage Between DLC C251 Pin 7, Circuit 70 (LB/WH), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage less than 3.0 volts?
- Yes : GO to X6.
- No : REPAIR circuit 70 (LB/WH). RETEST the communication to the RCM. 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 .
X6 CHECK CIRCUIT 70 (LB/WH) FOR A SHORT TO GROUND
- Key in OFF position.
- Measure the voltage between DLC C251 pin 7, circuit 70 (LB/WH), harness side and ground.
  
  Fig 5: Measuring Voltage Between DLC C251 Pin 7, Circuit 70 (LB/WH), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to X7.
- No : REPAIR circuit 70 (LB/WH). RETEST the communication to the RCM. 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 .
X7 CHECK CIRCUIT 70 (LB/WH) FOR AN OPEN
- Measure the resistance between RCM C310a pin 11, circuit 70 (LB/WH), harness side and the DLC C251 pin 7, circuit 70 (LB/WH), harness side.
  
  Fig 6: Measuring Resistance Between RCM C310a Pin 11, Circuit 70 (LB/WH), Harness Side And DLC C251 Pin 7, Circuit 70 (LB/WH), Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to X8.
- No : REPAIR circuit 70 (LB/WH). RETEST the communication to the RCM. 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.
X8 CONFIRM THE RCM FAULT
NOTE: Make sure the restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connector are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
- Connect: RCM C310a and C310b.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Did the diagnostic tool communicate with the RCM?
- Yes : Fault corrected. 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.
- No : INSTALL a new RCM. RETEST the communication to the RCM. 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.