Network Termination
The Controller Area Network (CAN) uses network termination to improve communication reliability. Termination modules are located at both ends of the network. As network messages are broadcast in the form of voltage signals, the network voltage signals are stabilized by the termination resistors.
Each termination module has an internal 120 ohm resistor that bridges across the positive and negative bus connection. With two 120 ohm resistors located in a parallel circuit configuration, the total network impedance, or total resistance, is 60 ohms.
Network termination improves bus message reliability by
- stabilizing bus voltage.
- eliminating electrical interference.
Gateway Module
The IPC is the gateway module, translating messages on the HS-CAN to MS-CAN and vice versa. This allows a message to be distributed throughout both networks.
The IPC is the only module on this vehicle that has this ability.
SPECIAL TOOLS Fluke 77-IV Digital Multimeter FLU77-4 or equivalent Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool Flex Probe Kit NUD105-R025D or equivalent
Scheme 85
Scheme 86
Scheme 87
Controller Area Network (CAN) Fault Tolerance
Note. The oscilloscope traces below are from the Integrated Diagnostic System (IDS) oscilloscope taken using the IDS pre-configured CAN settings. The traces are for both data (+) and data (-) taken simultaneously (2-channel) at a sample rate of 1 mega-sample per second (1MS/s) or greater.
Traces below are viewed at 500mV per division (vertical axis) and 20 microseconds (20μs) per division (horizontal axis). Readings taken with a different oscilloscope vary from those shown in illustration. Compare any suspect readings to a known good vehicle.
Scheme 88
Controller Area Network (CAN) Multiplex Messages
Modules on the CAN utilize simultaneous communication of two or more messages on the same network circuits. The following chart summarizes the messages sent and received on the network.
Note. This chart describes the specific High Speed Controller Area Network (HS-CAN) and Medium Speed Controller Area Network (MS-CAN) messages broadcast by each module, and the module(s) that receive the message.
| Broadcast Message | Originating Module | Network Type | Receiving Module(s) |
|---|---|---|---|
| A/C clutch engagement request HVAC | Module | MS-CAN | IPC |
| A/C clutch engagement request (gateway) | IPC | HS-CAN | PCM |
| A/C clutch engagement status | PCM | HS-CAN | IPC |
| A/C clutch engagement status (gateway) | IPC | MS-CAN | HVAC module |
| A/C recirculation mode request | PCM | HS-CAN | IPC |
| A/C recirculation mode request (gateway) | IPC | MS-CAN | HVAC module |
| ABS event in progress | ABS module | HS-CAN | PCM RCM |
| ABS Roll Stability Control (RSC®) chime malfunction status | ABS module | HS-CAN | IPC |
| ABS warning indicator request | ABS module | HS-CAN | IPC RCM |
| Accelerator pedal position | PCM | HS-CAN | ABS module IPC OCS module |
| Accelerometer and yaw sensor data | ABS module | HS-CAN | IPC |
| Accelerometer and yaw sensor data (gateway) | IPC | MS-CAN | GPSM |
| Accessory delay status | SJB | MS-CAN | ACM APIM BCM-B FCIM FDIM |
| Airbag deployment eCall confirmation | APIM | HS-CAN | RCM |
| Airbag deployment eCall notification | IPC | MS-CAN | APIM |
| Airbag deployment event data record | PCM | HS-CAN | RCM |
| Airbag deployment status | RCM | HS-CAN | IPC OCSM PCM |
| Airbag deployment status (gateway) | IPC | MS-CAN | SJB |
| Airbag warning indicator request | RCM | HS-CAN | IPC |
| Airbag warning indicator status | IPC | HS-CAN | RCM |
| Ambient lighting color | IPC | MS-CAN | BCM-B |
| Ambient lighting dimming level | IPC | MS-CAN | BCM-B |
| Ambient lighting status | BCM-B | MS-CAN | IPC |
| Ambient temperature, inferred | PCM | HS-CAN | ABS module IPC |
| Autolamp delay command | IPC | MS-CAN | SJB |
| Autolamp delay status | SJB | MS-CAN | IPC |
| Autolock command | IPC | MS-CAN | SJB |
| Autolock status | SJB | MS-CAN | IPC |
| Auto-unlock command | IPC | MS-CAN | SJB |
| Auto-unlock status | SJB | MS-CAN | IPC |
| Average fuel economy data | IPC | MS-CAN | ACM |
| Average fuel economy reset request (navigation) | ACM | MS-CAN | IPC |
| Axle ratio | PCM | HS-CAN | ABS module |
| Barometric pressure | PCM | HS-CAN | ABS module IPC |
| Barometric pressure (gateway) | IPC | MS-CAN | SJB |
| Belt-Minder® programming request | RCM | HS-CAN | IPC |
| Belt-Minder® warning status | RCM | HS-CAN | IPC |
| Belt-Minder® warning status (gateway) | IPC | MS-CAN | ACM |
| Brake (red) warning indicator request | SJB | MS-CAN | IPC |
| Brake fluid level low | SJB | MS-CAN | IPC |
| Brake fluid level low (gateway) | IPC | HS-CAN | ABS module |
| Brake lamp on demand | IPC | MS-CAN | SJB BCM-B |
| Brake lamp switch status | PCM | HS-CAN | ABS module IPC |
| Charging system status | PCM | HS-CAN | IPC |
| Charging system warning indicator request | PCM | HS-CAN | IPC PSCM |
| Compass display data | IPC | MS-CAN | ACM FDIM |
| Compass zone and calibration status | IPC | MS-CAN | ACM FDIM |
| Convertible top position status | BCM-B | MS-CAN | ACM HVAC module |
| Damper mode status | VDM | HS-CAN | ABS module IPC |
| Decklid ajar status | SJB | MS-CAN | IPC |
| Door ajar status | SJB | MS-CAN | IPC |
| Door lock command | SJB | MS-CAN | BCM-B |
| Door lock command source | SJB | MS-CAN | BCM-B |
| Engine coolant temperature | PCM | HS-CAN | ABS module IPC Engine temperature gauge |
| Engine coolant temperature (gateway) | IPC | MS-CAN | HVAC module |
| Engine fail-safe cooling mode status | PCM | HS-CAN | IPC |
| Engine fail-safe Electronic Throttle Control (ETC) warning indicator request | PCM | HS-CAN | IPC |
| Engine Malfunction Indicator Lamp (MIL) request | PCM | HS-CAN | IPC |
| Engine off timer | PCM | HS-CAN | ABS module IPC |
| Engine off timer (gateway) | IPC | MS-CAN | HVAC module |
| Engine oil life | PCM | HS-CAN | IPC |
| Engine RPM | PCM | HS-CAN | ABS module IPC PSCM |
| Engine RPM (gateway) | IPC | MS-CAN | APIM HVAC module |
| Engine torque data | PCM | HS-CAN | ABS module APIM |
| Engine torque reduction request | ABS module | HS-CAN | PCM |
| Engine turbocharger boost | PCM | HS-CAN | IPC |
| Engine type | PCM | HS-CAN | ABS module IPC |
| English/metric display (navigation) | ACM | MS-CAN | IPC |
| English/metric mode | IPC | MS-CAN | ACM HVAC module |
| Front Controls Interface Module (FCIM) button press data | FCIM | MS-CAN | ACM APIM IPC |
| Fuel cap off indicator request | PCM | HS-CAN | IPC |
| Fuel economy information | IPC | MS-CAN | ACM |
| Fuel flow data | PCM | HS-CAN | APIM IPC |
| Fuel level (instant) | IPC | HS-CAN | PCM |
| Fuel level status | IPC | MS-CAN | ACM |
| Fuel level status | IPC | HS-CAN | APIM |
| Fuel pump cutoff request | RCM | HS-CAN | IPC |
| Global Positioning System (GPS) data | Global Positioning System Module (GPSM) | MS-CAN | APIM |
| Headlamp high beam indicator request | SJB | MS-CAN | IPC |
| Headlamp low beam status | SJB | MS-CAN | IPC |
| Headlamps on warning chime command | SJB | MS-CAN | IPC |
| Hood ajar status | SJB | MS-CAN | IPC |
| HVAC button status | FCIM | MS-CAN | HVAC module |
| HVAC button status, navigation Audio Front Control Module (ACM) | ACM | MS-CAN | HVAC module |
| HVAC indicator status | HVAC module | MS-CAN | FCIM |
| HVAC module display data | HVAC module | MS-CAN | ACM |
| HVAC temperature display | HVAC module | MS-CAN | ACM FDIM |
| HVAC voice request | ACM | MS-CAN | HVAC module |
| Ignition switch position | SJB | MS-CAN | ACM APIM BCM-B FCIM FDIM GPSM HVAC module IPC |
| Ignition switch position (gateway) | IPC | HS-CAN | ABS module PCM PSCM |
| Integrated Keyhead Transmitter (IKT) programming request | IPC | MS-CAN | SJB |
| IKT programming status | SJB | MS-CAN | IPC |
| Illuminated entry/exit status | SJB | MS-CAN | BCM-B |
| Instrument illumination level | SJB | MS-CAN | ACM BCM-B FCIM FDIM HVAC module IPC |
| Interior courtesy lamp battery saver status | SJB | MS-CAN | BCM-B |
| Interior courtesy lamp delay status | SJB | MS-CAN | BCM-B |
| Interior courtesy lamp door status | SJB | MS-CAN | BCM-B |
| Interior courtesy lamp illuminated entry status | SJB | MS-CAN | BCM-B |
| Key-in-ignition status | SJB | MS-CAN | ACM APIM |
| Key-in-ignition warning chime command | SJB | MS-CAN | IPC |
| Low odometer status | IPC | MS-CAN | HVAC module SJB |
| Manual transmission clutch top travel switch status | PCM | HS-CAN | ABS module |
| Manual transmission upshift indicator request | PCM | HS-CAN | IPC |
| MyKey request | IPC | HS-CAN | ABS module PCM |
| Navigation rolling wheel count | ABS module | HS-CAN | IPC |
| Navigation rolling wheel count (gateway) | IPC | MS-CAN | ACM GPSM |
| Occupant Classification System (OCS) calibration data | OCSM | HS-CAN | RCM |
| OCS fault status | OCSM | HS-CAN | RCM |
| OCS sensor data | OCSM | HS-CAN | RCM |
| OCS serial number | OCSM | HS-CAN | RCM |
| Odometer rolling count | PCM | HS-CAN | APIM IPC |
| Park aid request | IPC | HS-CAN | PAM |
| Park aid status | PAM | HS-CAN | IPC |
| Park brake chime request | SJB | MS-CAN | IPC |
| Park brake status | SJB | MS-CAN | ACM IPC |
| Park brake status (gateway) | IPC | HS-CAN | ABS module PCM |
| Park lamp status | SJB | MS-CAN | ACM FCIM FDIM HVAC module IPC |
| Passenger seat belt buckle status | RCM | HS-CAN | OCSM |
| Passive Anti-Theft System (PATS) security data | IPC | HS-CAN | PCM |
| PATS security data | PCM | HS-CAN | IPC |
| PATS security data | IPC | MS-CAN | SJB |
| Perimeter alarm chime request | SJB | MS-CAN | IPC |
| Perimeter alarm courtesy lamp status | SJB | MS-CAN | BCM-B |
| Perimeter alarm event trigger source | SJB | MS-CAN | IPC |
| Perimeter alarm inclination armed status | SJB | MS-CAN | BCM-B |
| Perimeter alarm inclination sensor status | BCM-B | MS-CAN | SJB |
| Perimeter alarm inclination/intrusion sensor fault | BCM-B | MS-CAN | IPC |
| Perimeter alarm intrusion armed status | SJB | MS-CAN | BCM-B |
| Perimeter alarm intrusion sensor status | BCM-B | MS-CAN | SJB |
| PSCM fault status | PSCM | HS-CAN | IPC |
| Restraints Control Module (RCM) serial number | RCM | HS-CAN | ABS module OCSM |
| Remote start status | SJB | MS-CAN | APIM |
| Seat belt indicator request | RCM | HS-CAN | IPC |
| Seat belt warning chime request | RCM | HS-CAN | IPC |
| Seat belt warning chime status | IPC | HS-CAN | RCM |
| Slow vehicle speed puddle lamp status | SJB | MS-CAN | BCM-B |
| Speed control indicator status | PCM | HS-CAN | ABS module IPC OCS module |
| Stability control event in progress | ABS module | HS-CAN | PCM RCM |
| Stability control indicator status | ABS module | HS-CAN | IPC RCM PAM |
| Stability control message center text | ABS module | HS-CAN | IPC PCM PSCM |
| Steering wheel angle | PSCM | HS-CAN | ABS Module RCM PCM |
| Steering wheel angle offset | ABS module | HS-CAN | PSCM PAM |
| Tire revolutions per mile | PCM | HS-CAN | IPC |
| Tire size information | ABS module | HS-CAN | IPC PCM |
| Tire size information (gateway) | IPC | MS-CAN | ACM GPSM |
| Tire Pressure Monitoring System (TPMS) indicator command | SJB | MS-CAN | APIM IPC |
| TPMS sensor status | SJB | MS-CAN | APIM |
| TPMS system status | SJB | MS-CAN | APIM IPC |
| TPMS tire pressure data | SJB | MS-CAN | APIM IPC |
| Traction control disable switch status | ABS module | HS-CAN | IPC |
| Traction control event in progress | ABS module | HS-CAN | PCM RCM |
| Transmission malfunction indicator request | PCM | HS-CAN | IPC |
| Transmission overdrive cancel status | PCM | HS-CAN | IPC |
| Transmission selector (PRNDL) status | PCM | HS-CAN | ABS module IPC PAM |
| Transmission selector (PRNDL) status (gateway) | IPC | MS-CAN | ACM BCM-B GPSM SJB |
| Transmission shift in progress | PCM | HS-CAN | ABS |
| Transmission type | PCM | HS-CAN | ABS module IPC |
| Turn signal command | SJB | MS-CAN | IPC |
| Turn signal outage, LR | BCM-B | MS-CAN | SJB |
| Turn signal outage, RR | BCM-B | MS-CAN | SJB |
| Turn signal sequential command | SJB | MS-CAN | BCM-B |
| Vehicle speed | PCM | HS-CAN | ABS module IPC OCSM PAM PSCM VDM |
| Vehicle speed (gateway) | IPC | MS-CAN | ACM APIM BCM-B GPSM HVAC module SJB |
| Vehicle type information | PCM | HS-CAN | ABS module APIM IPC |
| Vehicle type information (gateway) | IPC | MS-CAN | ACM HVAC module |
| Vehicle Identification Number (VIN) information | PCM | HS-CAN | ABS module APIM IPC OCSM RCM |
| VIN information (gateway) | IPC | MS-CAN | APIM ACM HVAC module SJB |
| Wheel speed data | ABS module | HS-CAN | PCM PSCM |
CAN MODULE COMMUNICATION MESSAGE CHART