Module Communications Network: Overview Lincoln MKS I

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

TERMINAL REFERENCE

Principles of Operation

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 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 Instrument Panel Cluster (IPC) communicates with the scan tool and other network modules on the High Speed Controller Area Network (HS-CAN) and communicates with other network modules only on the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse(s)
2. Wiring, terminals or connectors
3. IPC

The Power Steering Control Module (PSCM) 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. PSCM (part of the Electronic Power Assist Steering (EPAS) system)

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 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 Head Up Display (HUD) 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. HUD module

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 Cruise-Control Module (C-CM) communicates with the scan tool through the HS-CAN .

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. C-CM

The Parking Aid Module (PAM) 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. PAM

The Headlamp Control Module (HCM) 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. HCM

The Steering Angle Sensor Module (SASM) 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. SASM

The Audio Control Module (ACM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Front Controls Interface Module (FCIM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Front Display Interface Module (FDIM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Global Positioning System Module (GPSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Interior Lighting Control Module (ILCM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Headlamp Control Module 2 (HCM-2) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. HCM-2

The Dual Climate Controlled Seat Module (DCSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Driver Seat Module (DSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

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

This pinpoint test is intended to diagnose the following

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

The HVAC module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The audio Digital Signal Processing (DSP) module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Audio DSP module

The Driver Door Module (DDM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

The Remote Function Actuator (RFA) module communicates with the scan tool and other network modules on the Medium Speed Controller Area Network (MS-CAN) and communicates with other network modules only on 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. RFA module

The Accessory Protocol Interface Module (APIM) communicates with the scan tool and other network modules on the High Speed Controller Area Network (HS-CAN) and communicates with other network modules only on the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following

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

An open circuit HS-CAN (+) or circuit HS-CAN (-) may cause intermittent or unreliable communication to all modules on the HS-CAN .

The following modules communicate on the HS-CAN

1. 4X4 control module (if equipped)
2. ABS module
3. Accessory Protocol Interface Module (APIM) (if equipped)
4. Cruise-Control Module (C-CM) (if equipped)
5. Head Up Display (HUD) module (if equipped)
6. Headlamp Control Module (HCM) (if equipped)
7. Instrument Panel Cluster (IPC) (gateway module)
8. Occupant Classification System Module (OCSM)
9. Parking Aid Module (PAM) (if equipped)
10. PCM
11. Power Steering Control Module (PSCM)
12. Remote Function Actuator (RFA) module (if equipped)
13. Restraints Control Module (RCM)
14. Steering Angle Sensor Module (SASM) (if equipped)

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. Wiring, terminals or connectors
2. 4X4 control module (if equipped)
3. ABS module
4. Accessory Protocol Interface Module (APIM) (if equipped)
5. Cruise-Control Module (C-CM) (if equipped)
6. Head Up Display (HUD) module (if equipped)
7. Headlamp Control Module (HCM) (if equipped)
8. Instrument Panel Cluster (IPC) (gateway module)
9. Occupant Classification System Module (OCSM)
10. Parking Aid Module (PAM) (if equipped)
11. PCM
12. Power Steering Control Module (PSCM) (part of the steering gear)
13. Remote Function Actuator (RFA) module (if equipped)
14. Restraints Control Module (RCM)
15. Steering Angle Sensor Module (SASM) (if equipped)

An open circuit Medium Speed Controller Area Network (MS-CAN) (+) or circuit MS-CAN (-) may cause intermittent or unreliable communication to all modules on the MS-CAN .

The following modules communicate on the MS-CAN

1. Accessory Protocol Interface Module (APIM) (if equipped)
2. Audio Control Module (ACM)
3. Audio Digital Signal Processing (DSP) module (if equipped)
4. Driver Door Module (DDM) (if equipped)
5. Driver Seat Module (DSM) (if equipped)
6. Dual Climate Controlled Seat Module (DCSM) (if equipped)
7. Front Controls Interface Module (FCIM)
8. Front Display Interface Module (FDIM)
9. Global Positioning System Module (GPSM) (if equipped)
10. Headlamp Control Module 2 (HCM-2) (if equipped)
11. HVAC module (if equipped)
12. Interior Lighting Control Module (ILCM) (if equipped)
13. Instrument Panel Cluster (IPC) (gateway module)
14. Remote Function Actuator (RFA) module (if equipped)
15. Smart Junction Box (SJB)

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors

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

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Accessory Protocol Interface Module (APIM) (if equipped)
3. Audio Control Module (ACM)
4. Audio Digital Signal Processing (DSP) module (if equipped)
5. Driver Door Module (DDM) (if equipped)
6. Driver Seat Module (DSM) (if equipped)
7. Dual Climate Controlled Seat Module (DCSM) (if equipped)
8. Front Controls Interface Module (FCIM)
9. Front Display Interface Module (FDIM)
10. Global Positioning System Module (GPSM) (if equipped)
11. Headlamp Control Module 2 (HCM-2) (if equipped)
12. HVAC module (if equipped)
13. Interior Lighting Control Module (ILCM) (if equipped)
14. Instrument Panel Cluster (IPC) (gateway module)
15. Remote Function Actuator (RFA) module (if equipped)
16. Smart Junction Box (SJB)

The scan tool is connected to the Data Link Connector (DLC) to communicate with modules on the High Speed Controller Area Network (HS-CAN) and the Medium Speed Controller Area Network (MS-CAN).

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

See also:
• SUPPLEMENTAL RESTRAINT SYSTEM
• SEATING