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

WARNING: This page is about a different car, the 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Cab & Chassis. 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.

G1 CHECK FOR DIAGNOSTIC TOOL COMMUNICATION WITH THE 4X4 CONTROL MODULE
- Verify diagnostic tool communication with the vehicle 4X4 control module.
  - If using the WDS, follow the directions and carry out the network test.
  - If using NGS+, verify that the vehicle and engine selection information is correct.
- WDS: Does the network test pass for the 4X4 control module?
  NGS+ : Are the vehicle and engine selections correct?
1. YES : REFER to the appropriate diagnostic tool manual for further diagnosis.
2. NO : Go to G2.

G2 CHECK IGNITION SWITCH STATUS PID

Key in ON position.

Monitor the ignition switch status PID.

Ignition Switch Position	PID	Expected Value
OFF	IGN_O/L	OFF
ACCESSORY	IGN_ACC	ACCY
RUN	IGN_R	RUN
START	IGN_S	START

Do the ignition switch PIDs match the ignition switch positions?

YES : Go to G3.
NO : CHECK the ignition switch. REFER to STARTING SYSTEM - GASOLINE ENGINES article for gasoline engines or STARTING SYSTEM - DIESEL ENGINE article for diesel engines. After the fault is repaired, CLEAR the DTC. REPEAT the self-test.

G3 CHECK FOR VOLTAGE INPUT TO THE FOUR WHEEL DRIVE 4X4 CONTROL MODULE

Disconnect: 4X4 Control Module C281a
Key in ON position.

Measure the voltage between 4X4 control module C281a and ground as follows:

Fig 1: Checking For Voltage Input To 4X4 Module

Courtesy of FORD MOTOR CO.

C281a Pin	Circuit
1	1306 (PK/WH)
2	1306 (PK/WH)
5	640 (RD/YE)
6	1002 (BK/PK)

Are the voltages at each pin greater than 9 volts?

YES : Go to G7.
NO : Go to G4.

G4 CHECK THE CENTRAL JUNCTION BOX (CJB) MINI-FUSES
- Check CJB mini-fuses:
  - 19 (10A).
  - 45 (10A).
  - 33 (15A).
- Are the fuses okay?
1. YES : Go to G5.
2. NO : INSTALL new fuses. REPAIR the circuits as necessary. REPEAT the self-test.
G5 CHECK FOR BATTERY VOLTAGE AT THE BJB AND CJB POWER INPUT FUSE CAVITIES
- Key in ON position.
- Measure the voltage between CJB input side fuse cavities and ground:
  - 19 (10A).
  - 45 (10A).
  - 33 (15A).
- Are the voltages greater than 9 volts?
1. YES : Go to G7.
2. NO : Go to G6.
G6 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 : Go to G7.
2. NO : CHECK the charging system. REFER to CHARGING SYSTEM - GENERAL INFORMATION article.
G7 CHECK THE GROUND CIRCUIT FOR AN OPEN
- Disconnect the battery ground cable. Refer to section CHARGING SYSTEM - GENERAL INFORMATION article
- Disconnect: 4X4 Control Module C281a
- Measure the resistance between C281a-3, circuit 57 (BK) and ground.
- Is the resistance less than 5 ohms?
1. YES : Go to G8.
2. NO : REPAIR the circuit. REPEAT the self-test.
G8 CHECK FOR A FLOATING GROUND
- Measure the voltage between C281a-3, circuit 57 (BK) and ground.
- Is voltage (greater than 1V) present?
1. YES : REPAIR the circuit. REPEAT the self-test.
2. NO : Go to G9.
G9 CHECK THE FOUR WHEEL DRIVE 4X4 CONTROL MODULE CONNECTOR
- Disconnect the 4X4 control module connectors C281a and C281b.
- CHECK for corrosion and/or pushed out pins.
- Is the connector corroded and/or damaged?
1. YES : REPAIR or CLEAN the connector(s) as necessary. Reconnect and REPEAT the self-test.
2. NO : INSTALL a new 4X4 control module. REFER to 4X4 Control Module in this article. TEST the system for normal operation.