Module Communications Network: Overview Ford Ranger II facelift

Note. The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Multiplexing is a method of sending 2 or more signals simultaneously over a single circuit. Multiplexing is used to allow 2 or more electronic modules (nodes) to communicate simultaneously over a twisted-wire pair [data (+) and data (-)] network. The information or messages that can be communicated on these wires consists of commands, status or data. The advantage of using multiplexing is to reduce the weight of the vehicle by reducing the number of redundant components and electrical wiring.

The vehicle has 2 module communication networks which are connected to the Data Link Connector (DLC), located under the instrument panel

1. High Speed Controller Area Network (HS-CAN)
2. Medium Speed Controller Area Network (MS-CAN)

Scheme 1

MODULE NAME REFERENCE

Principles of Operation

Note. The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Both the High Speed Controller Area Network (HS-CAN) and the Medium Speed Controller Area Network (MS-CAN) use an unshielded twisted-pair cable of data (+) and data (-) circuits. The HS-CAN operates at a maximum data transfer speed of 500 Kbps and is designed for real time information transfer and control. The MS-CAN operates at a maximum data transfer speed of 125 Kbps for bus messages and is designed for general information transfer.

Normal Operation

The PCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. PCM

The Occupant Classification System Module (OCSM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. OCSM

The Restraints Control Module (RCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Case ground open
4. RCM

The Smart Junction Box (SJB) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. SJB

The Instrument Cluster (IC) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. IC

The 4X4 control module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. 4X4 control module

The ABS module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. ABS module

The High Speed Controller Area Network (HS-CAN) is used for communication between the PCM, the Smart Junction Box (SJB), the ABS module, the Restraints Control Module (RCM), the 4X4 control module (if equipped) and the Instrument Cluster (IC).

In the event that 1 of the 2 network circuits ( HS-CAN + or HS-CAN -) becomes open to a module on the network, unreliable network communication to all modules on the network may result.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors

The High Speed Controller Area Network (HS-CAN) uses an unshielded twisted pair cable.

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. ABS module
4. PCM
5. Restraints Control Module (RCM)
6. Occupant Classification System Module (OCSM)
7. 4X4 control module
8. Instrument Cluster (IC)
9. Smart Junction Box (SJB)

The Satellite Digital Audio Receiver System (SDARS) module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN). The SDARS module shares the MS-CAN with the audio unit ( ACM ). While the SDARS module communicates with the scan tool on the MS-CAN , the audio unit ( ACM ) does not. All audio unit ( ACM ) diagnostics are carried out through the audio bezel test, refer to INFORMATION AND ENTERTAINMENT SYSTEMS .

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Audio unit ( ACM )
4. SDARS module

The scan tool is connected to the Data Link Connector (DLC) to communicate with the High Speed Controller Area Network (HS-CAN). A loss of ground or poor ground at the DLC may result in HS-CAN fault while the scan tool is connected.

A loss of ground or poor ground at the DLC may result in HS-CAN or MS-CAN faults while the scan tool is connected.

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. DLC
4. Scan tool