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

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.

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.