Anti-Lock Brake System (ABS) Module
The ABS module uses the high speed controller area network (CAN) for communication with the diagnostic tool and all the modules on the high speed CAN. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking.
For additional information, refer to VEHICLE DYNAMIC SYSTEMS .
Principles of Operation
The vehicle has 3 module communication networks
- high speed controller area network (CAN)
- medium speed CAN
- International Standards Organization (ISO) 9141 communications network
The diagnostic tool connects to the communication networks through the data link connector (DLC). The DLC allows a diagnostic tool access to diagnose and test the vehicle systems of any module on the communication networks.
All 3 communication networks are connected to the DLC. This makes diagnosis and testing of these systems easier by allowing 1 diagnostic tool to be able to diagnose and control any module on the 3 communication networks from 1 common connector. The DLC can be found under the instrument panel between the steering column and the driver door.
Normal Operation
The ABS module communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1827 (WH/LG) and 1828 (PK/LG). Check circuits 1827 (WH/LG) and 1828 (PK/LG) between the ABS module C135 and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to the ABS module C135, or damage to an in-line connector.
The audio unit communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 1847 (WH/OG) and 1848 (PK/OG). Check circuits 1847 (WH/OG) and 1848 (PK/OG) between the audio unit C290a and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the medium speed CAN circuits, damage to the DLC C251, damage to the audio unit connector, or damage to an in-line connector.
The instrument cluster communicates with the diagnostic tool through the high speed CAN, circuits 1827 (WH/LG) and 1828 (PK/LG). Check circuits 1827 (WH/LG) and 1828 (PK/LG) between the instrument cluster C220 and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to the instrument cluster C220, or damage to an in-line connector.
The instrument cluster communicates with the diagnostic tool through the medium speed CAN, circuits 1847 (WH/OG) and 1848 (PK/OG). Check circuits 1847 (WH/OG) and 1848 (PK/OG) between the instrument cluster C220 and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the medium speed CAN circuits, damage to the DLC C251, damage to the instrument cluster connector, or damage to an in-line connector.
The PCM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1827 (WH/LG) and 1828 (PK/LG). Check circuits 1827 (WH/LG) and 1828 (PK/LG) between the PCM C175b and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to the PCM C175b, or damage to an in-line connector.
The SJB communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 1847 (WH/OG) and 1848 (PK/OG). Check circuits 1847 (WH/OG) and 1848 (PK/OG) between the SJB C2280b and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the medium speed CAN circuits, damage to the DLC C251, damage to the SJB connector, or damage to an in-line connector.
The high speed CAN has an unshielded twisted pair cable, circuits 1827 (WH/LG) and 1828 (PK/LG). The anti-lock brake system (ABS) module, the instrument cluster and the powertrain control module (PCM) are all on the high speed CAN. The total resistance values from the module to the data link connector (DLC) must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the high speed CAN circuits, damage to the DLC C251, damage to one of the communications network module connectors, or damage to an in-line connector.
The medium speed CAN has an unshielded twisted pair cable, circuits 1847 (WH/OG) and 1848 (PK/OG). The audio unit, the instrument cluster, and the smart junction box (SJB) are all on the medium speed CAN. The total resistance values from the data link connector (DLC) C251 must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the medium speed CAN circuits, damage to the DLC C251, damage to one of the communications network module connectors, or damage to an in-line connector.
The restraint control module (RCM) communicates with the diagnostic tool through the ISO 9141 communications network, circuit 70 (LB/WH). Check circuit 70 (LB/WH) between the RCM C2041a and the data link connector (DLC) C251. The total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in the ISO 9141 communications network circuit, damage to the DLC C251, damage to the RCM C2041a, or damage to an in-line connector.
Under normal operation the diagnostic tool is connected to the data link connector (DLC) C251 to communicate with the high speed controller area network (CAN), medium speed CAN, and International Standards Organization (ISO) 9141 communication networks. If communication cannot be established, the diagnostic tool and the DLC C251 must be checked for damage. If the diagnostic tool and the DLC C251 are OK, circuits 570 (BK/WH), 1047 (LG/RD) and 1205 (BK) must be checked for an open condition.