Download - CAN BUS SCANIA
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23-04-27Info class Internal ETDP/sssszf/CAN bus properties
CAN bus properties
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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CAN networks on PGRT
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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CAN message
Bus idle Bus idle
Start of frame
Arbitration field
Control field
Data field
CRC error check field
Acknowledgement field
End of frame
IntermissionIdentifier
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Achieving the electrical bit
4V 2.5V 2.5V 1V
0 CAN high 1
0 CAN low 1
Time
Vol
tage
tran
smitt
ed
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Signal properties of a CAN bus
Recessive signal
Dominant signal
120 Ω
120 Ω
ECU
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Visualized with a Scope meterCAN_H
average voltage CAN_L average
voltage
CAN_L lowest peak voltage
CAN_H highest peak voltage
Recessive signal level
Dominant signal level
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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ECU electronic principle
Voltage converter
Power mode logic
Analogue inputs
Digital inputs
Digital outputs Drivers
Sensors Actuators High current actuators
Transceiver
CPU-module
CAN bus
Power supply
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Transceiver components
CAN bus
PNP
NPN
Inverter
Comparator
Resistor network
CAN Controller
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Transceiver function
CAN bus
0
+ _
0
CAN Controller
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Transceiver function
1
+_
1
CAN Controller
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Messages types: point to point
ECU ECU ECU ECU
ECU ECU ECU
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Messages types: broadcast
ECU ECU ECU ECU
ECU ECU ECU
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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CAN bus without terminal resistors
ECU ECU ECU ECU
ECU ECU ECU
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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CAN bus with terminal resistors
ECU ECU ECU ECU
ECU ECU ECU
Type of resistor mount it on the CAN connector block
Type of resistor- capacitor assy mount it into an ECU
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Red, Green and Yellow bus connector blocks
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Lowest possible specification
Enginemanagement
Visibility
Instrumentcluster
Yellowbus
Red bus
GREEN CAN BUS
Diagnostic connector
COO
COO
EMS
ICL
VIS
Yellow CAN BUS
RED CAN BUS
DIAGNOSTICS (SDP3)
APS
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Termination resistors
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Troubleshooting CAN buses
Scania multimeter 588 094 measure the integrity of the CAN wires and the CAN voltage levels: Measuring CAN bus resistance: able to trace wire and
termination resistors faults; able to trace open circuits or short circuit to ground or ECU’s internal supply (internal converter supplies with 5V).
Measuring CAN bus voltage: able to trace ECU’s internal faults or wire and termination resistors faults.
CAN messages can not be checked with a multimeter; instead the diagnose software is used to check the systems functionalities.
WSM 16:07-02 “Communication problems” shows measuring methods
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Measuring resistance
+15 OFF
31
CAN_H
CAN_L
60 Ω120 Ω
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Measuring resistance
+15 OFF
31
CAN_H
CAN_L
>1 kΩ
23-04-27Info class Internal ETDP/sssszf/CAN bus properties
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Measuring voltage
+15 ON
31
CAN_H
CAN_L
~2.6V~2.4V