LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 877 (Four Wheel Drive (4WD) Systems) >> Diagnostic Tests >> Four Wheel Drive (4WD) Systems - Electronic Shift >> Pinpoint Tests >> Pinpoint Test A: No Communication With the 4X4 Control Module >> Pinpoint Test A: No Communication With The 4X4 Control Module

Pinpoint Test A: No Communication With The 4X4 Control Module

WARNING: This page is about a different car, the 2007 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.
  1. A1 CHECK FOR SCAN TOOL COMMUNICATION WITH THE VEHICLE 
    • Verify scan tool communication with the vehicle.
    • Does the scan tool communicate with the PCM? 
    1. YES  : Go to  A2.
    2. NO  : REFER to the appropriate scan tool manual for further diagnosis.
  2. A2 CHECK FOR VOLTAGE INPUT TO THE 4X4 CONTROL MODULE 
    • Disconnect: 4X4 Control Module C281b
    • Measure the voltage between C281b-7, circuit SBP28 (GN/RD) and ground.
      Fig 1: Measuring Voltage Between C281B-7, Circuit SBP28 (GN/RD) & Ground
      GF0010603Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 9 volts? 
    1. YES  : Go to  A6.
    2. NO  : Go to  A3.
  3. A3 CHECK THE SMART JUNCTION BOX (SJB) FUSE 
    • Check the smart junction box (SJB) fuse 28 (15A).
    • Is the fuse OK? 
    1. YES  : Go to  A4.
    2. NO  : CHECK circuit SBP28 (GN/RD) for a short to ground or open. REPAIR as necessary. REPEAT the self-test.
  4. A4 CHECK FOR BATTERY VOLTAGE FROM THE SMART JUNCTION BOX (SJB) 
    • Key in ON position.
    • Measure the voltage between smart junction box (SJB) input side fuse cavity 28 and ground.
      Fig 2: Measuring Voltage Between Smart Junction Box (SJB) Input Side Fuse Cavity 28 & Ground
      GF0010604Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 9 volts? 
    1. YES  : REPAIR or INSTALL new components as necessary. REPEAT the self-test.
    2. NO  : Go to  A5.
  5. A5 CHECK THE BATTERY VOLTAGE WITH THE ENGINE RUNNING 
    • Start the engine.
    • Measure the battery voltage at the positive battery terminal.
    • Is the voltage greater than 9 volts? 
    1. YES  : REPAIR circuit SBP28 (GN/RD) at the SJB. REPEAT the self-test.
    2. NO  : CHECK the charging system. REFER to CHARGING SYSTEM - GENERAL INFORMATION article.
  6. A6 CHECK THE GROUND CIRCUIT FOR AN OPEN 
    • Disconnect the battery ground cable. Refer to BATTERY, MOUNTING AND CABLES article.
      • Fig 3: Measuring Resistance Between 4X4 Control Module C281b-3 Circuit GD174B And Ground
      GF0010605Courtesy of FORD MOTOR CO.
    • Measure the resistance between 4X4 control module C281b-3 circuit GD174B (BK/WH), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Disconnect all 4X4 control module connectors. CHECK for corrosion and/or pushed-out pins. The condition may have been caused by a loose or corroded connector. REPAIR or CLEAN as necessary.

      If not, INSTALL a new 4X4 control module. REFER to 4X4 Control Module  in this article. REPEAT the self-test.

    2. NO  : REPAIR the affected circuit(s). REPEAT the self-test.
scientia non olet · About LEMON Manuals