Pinpoint Test H: No International Standards Organization (ISO) 9141 Network Communication

WARNING: This page is about a different car, the 2005 Mercury Sable and 2005 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

H1 CHECK THE DLC C251 FOR DAMAGE
- Key in OFF position.
- Inspect the DLC C251.
- Is the DLC C251 OK?
- Yes : GO to H2.
- No : REPAIR the DLC C251. CARRY OUT the diagnostic tool data link test.
H2 CHECK RCM C310a FOR DAMAGE
- Key in OFF position.
- Deactivate the air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: RCM C310a.
- Inspect RCM C310a for damage.
- Is the RCM C310a OK?
- Yes : GO to H3.
- No : REPAIR the RCM C310a. CARRY OUT the diagnostic tool data link test.
H3 CHECK CIRCUIT 70 (LB/WH) BETWEEN THE DLC C251 AND THE RESTRAINTS CONTROL MODULE (RCM) C310a FOR AN OPEN
- Measure the resistance between the RCM C310a pin 11, circuit 70 (LB/WH), harness side and the DLC C251 pin 7, circuit 70 (LB/WH), harness side.
  
  Fig 1: 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 5 ohms?
- Yes : GO to H4.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
H4 CHECK THE ISO CIRCUIT FOR A SHORT TO GROUND
- Key in OFF position.
- Measure the resistance between the DLC C251 pin 7, circuit 70 (LB/WH), harness side and ground.
  
  Fig 2: Measuring Resistance 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 H5.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
H5 CHECK THE ISO CIRCUIT FOR A SHORT TO POWER
- Key in ON position.
- Measure the voltage between the DLC C251 pin 7, circuit 70 (LB/WH), harness side and ground.
  
  Fig 3: Measuring Voltage Between DLC C251 Pin 7, Circuit 70 (LB/WH), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage indicated?
- Yes : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
- No : GO to H6.
H6 CHECK FOR CORRECT RCM OPERATION
- Disconnect all the RCM connectors.
- Check for:
  - corrosion
  - push-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. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
- No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.