Pinpoint Test A: No Communication With The Smart Junction Box (SJB)

A1 CHECK THE SJB POWER CIRCUIT FOR AN OPEN
- Key in OFF position.
- Disconnect: SJB C2280a.
- Key in ON position.
- Measure the voltage between the SJB C2280a pin 12, circuit 1001 (WH/YE), harness side and ground.
  
  Fig 1: Measuring Voltage Between SJB C2280a Pin 12, Circuit 1001 (WH/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to A2.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
A2 CHECK THE SJB GROUND CIRCUIT FOR AN OPEN
- Key in OFF position.
- Connect: SJB C2280a.
- Disconnect: SJB C2280c.
- Measure the resistance between the SJB C2280c pin 18, circuit 57 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between SJB C2280c Pin 18 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnosis.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the test.