Module Communications Network: Overview — Mazda Tribute I (2000-2004)

Refer to the WIRING DIAGRAMS for schematic information.

Principles of Operation

The vehicle has two module communications networks. The standard corporate protocol (SCP) network, which is an unshielded twisted pair cable (data bus plus, circuit 914 [TN/OG] and data bus minus, circuit 915 [PK/LB]); and the international standards organization (ISO) 9141 network which is a single wire (circuit 70 [LB/WH]). The WDS or equivalent Tester can connect to both networks through the data link connector (DLC). This makes diagnosis and testing of these systems easier by allowing one smart tester to be able to diagnose and control any module on the two networks from one connector. The DLC can be found under the instrument panel between the steering column (near IP fuse to the left of panel).

The SCP communication network will remain operational even with the severing of one of the bus wires. Communications will also continue if one of the bus wires is shorted to ground or voltage, or if some, but not all, termination resistors are lost.

The ISO 9141 communication network does not permit inter-module communication. When the WDS or equivalent Tester communicates to modules on the ISO 9141 communication network, the WDS or equivalent Tester must ask for all information; the modules cannot initiate communications.

Unlike the SCP, the ISO 9141 communication network will not function if the wire is shorted to ground or battery voltage. Also, if one of the modules on the ISO 9141 communication network loses power or shorts internally, communications to that module will fail.

There are two modules linked to the SCP communication network and three modules linked to the ISO 9141 communication network.

The powertrain control module (PCM) is on the SCP communication network. The PCM controls the engine for better fuel economy, emissions control and failure mode detection and storage. For additional information, refer to COMMUNICATIONS NETWORK .

The passive anti-theft system (PATS) is integrated into the PCM module. The PCM/PATS system is connected to the vehicle electrical system, the transceiver module, the vehicle SCP communications network and the vehicle anti-theft indicator located in the instrument cluster (IC). The PCM module uses a microprocessor to control the system functions as well as illumination of the anti-theft indicator. The illumination command is sent from the PCM through the SCP communications network to the IC, which in turn sends power to the anti- theft indicator. The PCM module microprocessor stores the ignition key codes in non-volatile memory. The PCM and IC modules can be diagnosed through the data link connector. For additional IC information, refer to INSTRUMENT CLUSTER .

The restraint control module (RCM) is on the ISO 9141 communication network. The RCM controls the deployment of the air bags based on sensor input. For additional information, refer to AIR BAG RESTRAINT SYSTEMS for AIR BAG AND SAFETY BELT PRETENSIONER SUPPLEMENTAL RESTRAINT SYSTEM (SRS).

The generic electronic module (GEM) is on the ISO 9141 communication network. The GEM controls a variety of systems

Rear Wiper
Cargo Lamps
Interior Lamps
Exterior Lamps
Accessory Delay
Perimeter Anti-Theft (If Equipped)

For additional GEM information, refer to COMMUNICATIONS NETWORK .

The anti-lock brake system (ABS) control module is on the ISO 9141 communication network. The ABS module controls the brake pressure to the four wheels to keep the vehicle under control while braking. For additional information, refer to ANTI-LOCK/TRACTION CONTROL - TRIBUTE article.

Scheme 1

Scheme 1: Inspection and Verification

Verify the customer concern.
Visually inspect for obvious signs of electrical damage. Visual Inspection Chart
If the concern remains after the inspection, connect the WDS or equivalent Tester to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the WDS or equivalent Tester menu. If the WDS or equivalent Tester does not communicate with the vehicle: Check that the program card is correctly installed. Check the connections to the vehicle. Check the ignition switch position is in RUN.
If the WDS or equivalent Tester still does not communicate with the vehicle, go to «PINPOINT TEST 1: NO MODULE/NETWORK COMMUNICATION - SCP LINK»(ref-173500-S24762252312005050300000) .

Some modules support the ability to change specified factory configuration settings and preset preference items. The process used to change the settings and customer preference items is module configuration. There are two different methods of module configuration

Programmable module installation (PMI).
Customer preference items.

There are three storage locations for module configuration information. One primary storage location and two secondary (or backup) storage locations.

Primary location is the memory of the specific module.
First backup location is the VID block memory of the powertrain control module (PCM).
Second backup is the As-Built Data Center.

During PMI, the WDS or equivalent Tester will attempt to extract the module configuration information from the module to be changed. If this is unsuccessful, the WDS or equivalent Tester will use the first backup and attempt to extract the module configuration information from the VID block in the PCM. If this also fails, the WDS or equivalent Tester will display instructions to contact the As-Built Data Center.

Vehicle Identification (VID) Block

Note. Make sure to use the flash cable when programming calibrations or running a PMI routine on the PCM.

Note. When carrying out a PMI routine on any non-PCM module, use the OBDII cable.

Note. Flash programming powertrain calibrations onto the PCM is different than PMI. It has no effect on the backup data in the VID block memory area of the PCM.

The PCM contains a memory area called a vehicle identification (VID) block. A portion of the VID block is used to store the backup data for each programmable module on the vehicle.

The VID block is the first backup of information when using the PMI configuration method. If the WDS or equivalent Tester cannot retrieve option content information from the suspect module, the WDS or equivalent Tester will attempt to extract backup information from the VID block of the PCM.

The VID block is not related to or affected by the powertrain calibration information stored in the PCM. If a new powertrain calibration has been flashed onto the PCM, the VID block will not be affected.

If using the PMI routine to install a new PCM, the WDS or equivalent Tester will reprogram only VID information.

The engine calibration information may still need to be flashed.

As-Built Data Center

The As-Built Data Center keeps a record of the vehicle configuration in a database that is retrievable using the VIN. The As-Built Data Center records the applicable module configurations stored in each module before the vehicle leaves the factory. The As-Built Data Center will always reflect the original build of the vehicle as it left the factory.

The generic electronic module (GEM) constantly monitors its subsystems for concerns. If a concern is found in one of the subsystems, the GEM will record the concern in the form of a diagnostic trouble code (DTC).

The ignition switch position is very important to the GEM function. Erratic or unexpected GEM function can often be traced to problems with these GEM inputs.

The GEM controls a variety of systems

Interval Rear Window Wiper
Battery Saver
Illuminated Entry
Headlamp Control
Interior Lamp Control
Power Door Locks
Remote Keyless Entry (RKE)
Accessory Delay
Door Ajar Output Control

Scheme 2

Scheme 2: Inspection and Verification

Verify the customer concern by operating the system in question.
Visually inspect for obvious signs of mechanical and electrical damage. Visual Inspection Chart
If the concern remains after the inspection, connect the WDS or equivalent Tester to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the WDS or equivalent Tester menu. If the WDS or equivalent Tester does not communicate with the vehicle: Check that the program card is correctly installed. Check the connections to the vehicle. Check the ignition switch position.
If the WDS or equivalent Tester still does not communicate with the vehicle, refer to the WDS or equivalent Tester manual.
Carry out the DATA LINK DIAGNOSTICS test. If the WDS or equivalent Tester responds with: CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to «COMMUNICATIONS NETWORK»(ref-173500-S38247412152005031600000) . NO RESP/NOT EQUIPPED for generic electronic module (GEM), go to «PINPOINT TEST 1: NO COMMUNICATION WITH THE GENERIC ELECTRONIC MODULE (GEM)»(ref-173500-S40848950682005031600000) . SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.
If the DTCs retrieved are related to the concern, go to the «GEM Diagnostic Trouble Code (DTC) Index»(ref-173500-S28459354622005031600000) to continue diagnostics.
If no DTCs related to the concern are retrieved, refer to the appropriate article to continue diagnostics.