Can - Triumph Rocket III Classic Service Manual

General Information
Splices
Splices are probably the most common cause of wiring
faults after connectors. Splices are made where two or
more wires come together and diverge in different
directions, usually to feed a different circuit.
To locate a splice, it is necessary to peel back the insulation
and examine the splice for its integrity. The most common
fault is where one of the wires at the joint has come adrift
usually causing the circuit it feeds or earths to become
'dead'.
Switches
To check a switch, set the multimeter to resistance/
continuity and probe the two pins that form a closed
circuit when the switch is pushed. If the switch is working
correctly, the resistance should register or the meter will
bleep.
Relays
All relay cases have a circuit path engraved on them
showing the circuit path across the electromagnet and the
switch. Before making any checks, first note the pin
designations, current paths, and whether or not there is a
diode in either circuit path.
Diode
86 ......
--1 __ ......
• • 87
Electromagnet
85
e--_.....J 30
Make continuity checks across the electromagnet first,
usually from pin 86 (positive) to pin 85 (negative). If a
diode appears in the circuit use the diode check on the
multi meter (volts scale) in the direction of current flow. If
there is no diode, use the resistance check facility. An
open circuit or unusually high resistance value indicates a
faulty relay.
To check the switch side, apply a 12 volt supply between
pins 86 and 85. With the supply connected the relay
should be heard to click and there should be continuity
between pins 30 and 8Z An open circuit indicates a faulty
relay.
CAN (Controller Area Networking)
CAN (sometimes called CAN bus) is a protocol for data
communication between Electronic Control Modules
(ECMs). Each ECM on the network is connected by a
single pair of twisted wires (or bus) which are used for the
transmission of vehicle sensor data. By using CAN, the
overall number of system sensors, and the amount of
cabling required to allow ECMs to communicate with
each other is greatly reduced.
This saves cost, weight and space, and makes the system
more reliable, as the physical number of wires and
connections is reduced.
Pair of Twisted
R
Wires
B28
4
U
s Instrument
B27
Pack
r- 16
ECM
1
A34
KY 3
2
~
Vehicle Speed
Sensor
Extract from the circuit diagram showing CAN
connection between ECMs
CAN works by each ECM sending out 'packets' of
information (such as engine speed or fuel consumption
information) on to the network bus (note that the network
must be free of data before any ECM is allowed to
transmit>. This data is given a priority according to its
importance (for example 'engine speed' may have a
higher priority than 'Iow fuel level'), so that even if two
ECMs send data at the same time, high priority
information is always sent first. Lower priority data is then
resent after the high priority data has been received by all
ECMs on the network.
The receiving ECM confirms the data has been received
correctly and that the data is valid, and this information is
then used by the ECM as necessary. Specific data not
required by an ECM will still be received and
acknowledged as correct but then disregarded (for
example if an ECM does not require 'clutch switch
position' information, this data packet would be ignored).
This allows for a very high speed system of
communication, which is also very reliable. Should one
ECM fail or transmit corrupted or otherwise incorrect
messages, none of the other ECMs on the network will be
affected, and after a certain time that ECM will be
prevented from transmitting further messages until the
fault is rectified. This stops the ECM from clogging the
network with incorrect data and preventing other
messages from getting through. The fault would then be
reported by a DTC (Diagnostic Trouble Code).
Triumph currently use CAN for communication between
the engine ECM and the instruments.
1.18
SelVice Manual - Rocket Ill/ Classic / Touring