System Diagnostics; On-Board Fault Detection System - Triumph Thunderbird Service Manual

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 Triumph
diagnostic software. Full details of the Triumph
diagnostic software operation and how to interpret
the results are given in the Triumph Diagnostic Tool
User Guide.
The software is connected, via an interface cable, to the
motorcycle using a dedicated diagnostic plug situated
beneath the left hand side panel. By using a dedicated
plug, no electrical connectors associated with the system
are disturbed, reducing potential connector damage.
The software 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 still 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 (Malfunction 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
noc
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 software.
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.
10.22
SelVice Manual - Thunderbird