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

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

A1 CHECK THE SJB VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Key in OFF position.
Disconnect: SJB C2280a.
Disconnect: SJB C2280g.

Using the following table, measure the voltage between the SJB, harness side and ground:

SJB CONNECTOR-PIN REFERENCE

SJB Connector-pin	Circuit
C2280a-29	1231 (RD/WH)
C2280g-l	906 (RD/OG)
C2280g-2	905 (GY/LB)

Fig 1: Checking SJB Voltage Supply Circuit

Courtesy of FORD MOTOR CO.

Are the voltages greater than 10 volts?

Yes : GO to A2.
No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

A2 CHECK THE SJB GROUND CIRCUIT FOR AN OPEN
- Connect: SJB C2280g.
- Disconnect: SJB C2280e.
- Measure the resistance between the SJB C2280a-30, circuit 1203 (BK/LB), harness side and ground; and between the SJB C2280e-3, circuit 1205 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between SJB C2280A-30 Circuit 1203 (BK/LB)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnosis.
- No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.