Precautions In Diagnosing Troubles - Suzuki Liana RH413 Service Manual

10C-1 Immobilizer Control System:
Immobilizer Control System
Control Systems

Precautions in Diagnosing Troubles

Precautions in Identifying DTC
ECM
[Vehicle not equipped with immobilizer indicator
lamp]
• Before identifying DTC indicated by malfunction
indicator lamp or SUZUKI scan tool, don't disconnect
couplers from ECM, battery cable from battery, ECM
ground wire harness from engine. Such disconnection
clears DTCs for engine and emission control system
and immobilizer control system stored in memory of
ECM.
• If abnormality or malfunction exists in two or more
areas, malfunction indicator lamp indicates applicable
codes three times each. And, flashing of these codes
is repeated as long as diagnosis terminal is grounded
and ignition switch is at ON position.
• When ECM detects a trouble in both engine and
emission control system and immobilizer control
system, malfunction indicator lamp indicates DTCs of
both systems alternately while the ignition switch is
turned ON and the diagnosis terminal is grounded.
• Take a note of DTC indicated first.
[Vehicle equipped with immobilizer indicator lamp]
• Before identifying DTC indicated through SUZUKI
scan tool, don't disconnect couplers from ECM,
battery cable from battery, ECM ground wire harness
from engine. Such disconnection clears DTCs for
engine and emission control system and immobilizer
control system stored in memory of ECM.
• Take a note of DTC indicated first.
Immobilizer Control Module
Take a note of DTC indicated first.
Precautions
Intermittent troubles
S3RH0AA300001 There is case where SUZUKI scan tool or malfunction
indicator lamp (if not equipped with immobilizer indicator
lamp) indicates a DTC representing a trouble which
occurred only temporarily and has gone. In such case, it
may occur that good parts are replaced unnecessarily.
To prevent such service, be sure to follow instructions
given below when checking by using "Immobilizer
Control System Check".
• When trouble can be identified, it is not an intermittent
one:
Check coil antenna, ignition key, wires and each
connection. If they are all in good condition, substitute
a known-good ECM and recheck.
• When trouble can not be identified but SUZUKI scan
tool or malfunction indicator lamp (if not equipped with
immobilizer indicator lamp) indicate a DTC:
Diagnose trouble by using that code No. If ignition
key, coil antenna, wires and each connection are all in
good condition, turn OFF ignition switch and then ON.
Then, check what SUZUKI scan tool indicates. Only
when it indicates a DTC again, substitute a known-good
ECM or Immobilizer Control Module and check again. If
it doesn't indicate a DTC, it means that an intermittent
trouble did occur and has gone. In this case, check wires
and connections carefully again.