Anti-Lock Brake System (ABS) Module
The ABS module uses the high speed controller area network (CAN) for communication with the diagnostic tool. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking. For additional information, refer to ANTI-LOCK CONTROL.
Principles of Operation
The vehicle has 3 module communications networks
- high speed controller area network (CAN)
- medium speed CAN
- international standards organization (ISO) 9141 communications network
The high speed CAN is a high speed communications network used for the anti-lock brake system (ABS) module, the differential electronic module (DEM) (if equipped), the transmission control module (TCM) - 6-speed transaxle, TCM - continuously variable transaxle (CVT), the instrument cluster, the powertrain control module (PCM) and the restraint control module (RCM) communication. The medium speed CAN is used for the audio unit, the driver seat module (DSM) (if equipped), the dual automatic temperature control (DATC) module (if equipped), the digital versatile disc (DVD) player (if equipped), the instrument cluster, and the smart junction box (SJB) communications. The CAN remains operational with the severing of 1 of the CAN circuits or if the data minus circuit is shorted to ground. Communication may continue if one of the termination resistors is lost. The CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The CAN also does not remain operational if the data minus circuit is shorted to voltage.
The medium speed CAN has an unshielded twisted pair cable, data plus circuit 2180 (WH/BK) and data minus circuit 2181 (BK/YE). The high speed CAN also has an unshielded twisted pair cable, data plus circuit 1908 (WH) and data minus circuit 1909 (BK). The ISO 9141 communications network is a single circuit communications network, circuit 70 (LB/WH). All 3 communications networks are connected to the data link connector (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 communications networks from one connector. The DLC can be found under the instrument panel between the steering column and the audio unit.
The ISO 9141 communications network does not permit intermodule communication. When the diagnostic tool communicates to modules on the ISO 9141 communications network, the diagnostic tool must ask for all information; the modules cannot initiate communications. The ISO 9141 communications network does not function if the circuit is shorted to ground or battery voltage. Also, if one of the modules on the ISO 9141 communications network loses power or shorts internally, communications to that module fail. The ISO 9141 communications network is used to communicate with the parking aid module (PAM).
Normal Operation
The DEM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) between the DEM C3269 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 DEM C3269, or a problem in an in-line connector.
The ABS module communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) 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 a problem in an in-line connector.
The TCM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) between the TCM C199 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 TCM C199, or a problem in an in-line connector.
The TCM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) between the TCM C168 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 TCM C168, or a problem in an in-line connector.
The instrument cluster communicates with the diagnostic tool and all the modules on the high speed controller area network (CAN) through circuits 1908 (WH) and 1909 (BK). The instrument cluster also communicates with all the modules on the medium speed CAN, circuits 2180 (WH/BK) and 2181 (BK/YE), while serving as a gateway between the medium speed CAN and the high speed CAN. The CAN remains operational with the severing of one of the CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) 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 a problem in an in-line connector.
The PCM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. The PCM and instrument cluster share communications network termination responsibilities with the use of a split termination resistor in each module. Check circuits 1908 (WH) and 1909 (BK) 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 a problem in an in-line connector.
The RCM communicates with the diagnostic tool through the high speed controller area network (CAN), circuits 1908 (WH) and 1909 (BK). The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. Check circuits 1908 (WH) and 1909 (BK) between the RCM C310b 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 RCM C310b, or a problem in an in-line connector.
The audio unit communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 2180 (WH/BK) and 2181 (WH/BK). The medium speed CAN remains operational with the severing of one of the medium speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The medium speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The medium speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (DLC) C251, damage to the audio unit connector, or damage to an in-line connector.
The DSM communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 2180 (WH/BK) and 2181 (BK/YE). The medium speed CAN remains operational with the severing of one of the medium speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The medium speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The medium speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (DLC) C251, damage to the DSM connector, or damage to an in-line connector.
The DATC module communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 2180 (WH/BK) and 2181 (BK/YE). The medium speed CAN remains operational with the severing of one of the medium speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The medium speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The medium speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (DLC) C251, damage to the DATC module connector, or damage to an in-line connector.
The DVD player communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 2180 (WH/BK) and 2181 (BK/YE). The medium speed CAN remains operational with the severing of one of the medium speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The medium speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The medium speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (DLC) C251, damage to the DVD player connector, or damage to an in-line connector.
The parking aid module (PAM) communicates with the diagnostic tool through the international standards organization (ISO) 9141 communications network circuit 70 (LB/WH). If circuit 70 (LB/WH) becomes open or shorted to ground, communications to that module are not possible. Check circuit 70 (LB/WH) between the PAM C3267 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 PAM connector, or damage to an in-line connector.
The high speed CAN has an unshielded twisted pair cable, circuits 1908 (WH) and 1909 (BK). The differential electronic module (DEM) (if equipped), the anti-lock brake system (ABS) module, the transmission control module (TCM) - 6-speed transaxle, the TCM - continuously variable transaxle (CVT), the instrument cluster, the powertrain control module (PCM) and the RCM all use the high speed CAN. The high speed CAN remains operational with the severing of one of the high speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The high speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The high speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (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 2180 (WH/BK) and 2181 (BK/YE). The audio unit, the driver seat module (DSM) (if equipped), the dual automatic temperature control (DATC) module (if equipped), the digital versatile disc (DVD) player (if equipped), the instrument cluster, and the smart junction box (SJB) are all on the medium speed CAN. The medium speed CAN remains operational with the severing of one of the medium speed CAN circuits or if the data minus circuit is shorted to ground. Communication may also continue if one of the termination resistors is lost. The medium speed CAN does not remain operational if the data plus circuit is shorted to ground or shorted to voltage. The medium speed CAN also does not remain operational if the data minus circuit is shorted to voltage. 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 data link connector (DLC) C251, damage to one of the communications network module connectors, or damage to an in-line connector.
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 communications networks. If communication can not 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 40 (LB/WH), 1203 (BK/LB), and 1205 (BK) must be checked for an open condition.
See also:
• SUPPLEMENTAL RESTRAINT SYSTEM
• VIDEO SYSTEM