Module Communications Network: Overview — Ford Escape I facelift 2 (2007-2012)

Vehicle communication utilizes both ISO 9141 and Controller Area Network (CAN) communications. ISO 9141 is used for diagnostic use only while CAN allows many modules to communicate with each other on a common network. CAN in-vehicle networking is a method for transferring data among distributed electronic modules via a serial data bus.

Without serial networking, inter module communication requires dedicated, point to point wiring resulting in bulky, expensive, complex, and difficult to install wiring harnesses. Applying a serial data network reduces the number of wires, combining the signals on a single network.

Information is sent to the individual control modules that control each function.

The vehicle has 3 module communication networks

ISO 9141
Medium Speed Controller Area Network (MS-CAN)
High Speed Controller Area Network (HS-CAN)

All 3 networks are connected to the Data Link Connector (DLC). This makes diagnosis and testing of these systems easier by allowing one scan tool to be able to diagnose and control any module on the 3 networks from one connector. The DLC can be found under the instrument panel between the steering column and the Audio Control Module (ACM).

Scheme 1

Scheme 1: Network Topology

Module Name	Network Type	Termination Module
4X4 control module (if equipped)	HS-CAN	No
ABS module	HS-CAN	No
Accessory Protocol Interface Module (APIM)	MS-CAN	No
Accessory Protocol Interface Module (APIM)	HS-CAN	No
Audio Control Module (ACM)	MS-CAN	No
HVAC module	MS-CAN	No
Front Controls Interface Module (FCIM) (if equipped)	MS-CAN	No
Front Display Interface Module (FDIM)	MS-CAN	No
Instrument Cluster (IC) (gateway module)	HS-CAN	Yes
Instrument Cluster (IC) (gateway module)	MS-CAN	Yes
Occupant Classification System Module (OCSM)	HS-CAN	No
Parking Aid Module (PAM) (if equipped)	ISO 9141	N/A
PCM	HS-CAN	Yes
Power Steering Control Module (PSCM)	HS-CAN	No
Restraints Control Module (RCM)	HS-CAN	No
Satellite Digital Audio Receiver System (SDARS) module	MS-CAN	No
Smart Junction Box (SJB)	MS-CAN	Yes

MODULE NAME REFERENCE

ISO 9141 Network Operation

The ISO 9141 communications network is a single wire network, used for diagnostic purposes only.

The ISO 9141 communications network is used for the following module

Parking Aid Module (PAM) (if equipped)

Medium Speed Controller Area Network (MS-CAN) Operation

The MS-CAN communicates using bussed messages. The MS-CAN has an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, this network allows sharing of information between all modules on the network.

The MS-CAN is a medium speed communication network used for the following modules

Accessory Protocol Interface Module (APIM) (if equipped)
Audio Control Module (ACM)
Front Controls Interface Module (FCIM) (if equipped)
Front Display Interface Module (FDIM)
HVAC module
Instrument Cluster (IC)
Satellite Digital Audio Receiver System (SDARS) module (if equipped)
Smart Junction Box (SJB)

High Speed Controller Area Network (HS-CAN) Operation

The HS-CAN communicates using bussed messages. The HS-CAN uses an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, this network allows sharing of information between all modules on the network.

The HS-CAN is a high speed communication network used for the following modules

4X4 control module (if equipped)
ABS module
APIM (if equipped)
Instrument Cluster (IC)
Occupant Classification System Module (OCSM)
PCM
Power Steering Control Module (PSCM)
Restraints Control Module (RCM)

The ISO 9141 communications network is a single wire network, used for diagnostic purposes only.

The ISO 9141 communications network is used for the following module

Parking Aid Module (PAM)

The MS-CAN is a medium speed communication network used for the following modules

Accessory Protocol Interface Module (APIM) (if equipped)
Audio Control Module (ACM)
HVAC module
Front Controls Interface Module (FCIM)
Front Display Interface Module (FDIM)
Instrument Cluster (IC)
Satellite Digital Audio Receiver System (SDARS) module
Smart Junction Box (SJB)

The HS-CAN is a high speed communication network used for the following modules

4X4 control module
ABS module
APIM (if equipped)
Battery Control Module (BCM)
Instrument Cluster (IC)
Occupant Classification System Module (OCSM)
PCM
Power Steering Control Module (PSCM)
Restraints Control Module (RCM)
Transmission Control Module (TCM)

Principles of Operation

Vehicle communication utilizes both International Standards Organization (ISO) 9141 and Controller Area Network (CAN) communications. ISO 9141 is used for diagnostic use only, and CAN is a method for transferring data among distributed electronic modules via a serial data bus.

The vehicle is equipped with 3 module communication networks

ISO 9141
Medium Speed Controller Area Network (MS-CAN)
High Speed Controller Area Network (HS-CAN)

Normal Operation

The PCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the PCM. Voltage for the PCM is provided by circuit CBB28 (GY/VT) or SBB05 (GY/RD). Circuit GD122 (BK) provides ground.