Triumph Rocket III Service Manual page 176

Fuel System/Engine Management
System Diagnostics
The engine management system has an on-board
diagnostics feature which allows service technicians
to retrieve stored data from the ECM using a Triumph
service tooi. Full details of the tool's operation and
how to interpret the results are given elsewhere in
this section.
The tooi is connected to the motorcycle using a
dedicated diagnostic plug situated beneath the seats.
By using a dedicated plug, no electricai connectors
associated with the system are disturbed, reducing
potential connector damage.
The tool allows the user to retrieve data associated
with the system sensors and actuators, test various
component functions, read build data and make minor
adjustments to the set-up of the system. The data
and tests available are described on the following
pages.
On-board Fault Detection System
The on-board diagnostic system has two stages to
fault detection. When a fault is detected, the DSM
(Diagnostic Status Manager) raises a flag to indicate
that a fault is present and increments a counter. The
counter checks the number of instances that the fault
is noted. For example, if there is a fault in the
crankshaft position sensor, the counter will increment
its count each time the crankshaft turns through 360°,
provided the fault is stili present.
When the count begins, the fault is detected but not
confirmed. If the fault continues to be detected and
the count reaches a pre-determined threshold, the
fault becomes confirmed. If the fault is an emissions
related fault or a serious malfunction affecting engine
performance, a DTC (Diagnostic Trouble Code) and
freeze-frame data will be logged in the ECM's
memory and the MIL (Malfunction Indicator Lamp) on
the motorcycle instrument panel is illuminated. Once
a fault is confirmed, the number of warm-up cycles
made by the engine is counted. If the fault clears, the
warm-up cycle counter will extinguish the MIL
(Maifunction Indicator Lamp) at a pre determined
count. and erase the DTC and freeze frame data from
the ECM memory at another (higher) count.
A single warm-up cycle is deemed to have taken
place when the following criteria have been met:
• The coolant temperature must be raised to 72°C
or more.
• The coolant temperature must have risen by
23°C or more from its start temperature. when
nOc
is reached.
• A controlled power-down sequence must take
place.
Note:
• When a fault has been rectified, the MIL
will remain illuminated until sufficient non-
fault warm-up cycles have taken place to
turn it off. The MIL will be immediately
extinguished if, after first rectifying the
fault, the DTC (diagnostic trouble code)
that caused the MIL illumination is erased
from the ECM memory using the Triumph
diagnostic tool.
Note:
• In most cases, when a fault is detected, the
engine management system will revert to a
'limp-home' mode. In this mode, the
engine will still function though the
performance and fuel economy may be
marginally affected. In some cases, the
rider may not notice any appreciable
difference from normal operation.
Triumph Diagnostic Tool
Described on the following pages is the range of
information which can be retrieved from the ECM's
memory and the adjustments which can be performed
using the Triumph service diagnostic tooi.
The tables indicate which tests are performed by the
on-board system and what information can be
retrieved by the Triumph diagnostic tooi.
Full details of how to operate the tool and how to
interpret the data follow later in this section.
11.22
Service Manual - Rocket III