Precaution In Diagnosing Trouble - Suzuki Ignis Service Manual

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PRECAUTION IN DIAGNOSING TROUBLE

• Do not disconnect couplers from ECM, battery cable from battery, ECM ground wire harness from engine or
main fuse before confirming diagnostic information (DTC, freeze frame data, etc.) stored in ECM memory.
Such disconnection will erase memorized information in ECM memory.
• Diagnostic information stored in ECM memory can be cleared as well as checked by using SUZUKI scan
tool (Tech-1) or generic scan tool (Vehicle with immobilizer indicator lamp). Before using scan tool, read its
Operator's (Instruction) Manual carefully to have good understanding as to what functions are available and
how to use it.
• Priorities for diagnosing troubles (Vehicle with immobilizer indicator lamp).
If two or more DTCs are stored, proceed to the flow table of the DTC which has detected earliest in the order
(it can be identified by referring to freeze frame data) and follow the instruction in that table.
If no instructions are given, troubleshoot diagnostic trouble codes according to the following priorities.
– Diagnostic trouble codes (DTCs) other than DTC P0171/P0172 (Fuel system too lean/too rich), DTC
P0300/P0301/P0302/P0303/P0304 (Misfire detected) and DTC P0400 (EGR flow malfunction)
– DTC P0171/P0172 (Fuel system too lean/too rich) and DTC P0400 (EGR flow malfunction)
– DTC P0300/P0301/P0302/P0303/P0304 (Misfire detected)
• Be sure to read "Precautions for Electrical Circuit Service" in Section 0A before inspection and observe what
is written there.
• ECM Replacement
When substituting a known-good ECM, check for following conditions. Neglecting this check may cause
damage to a known-good ECM.
– Resistance value of all relays, actuators is as specified respectively.
– MAP sensor and TP sensor are in good condition and none of power circuits of these sensors is shorted
to ground.
Over 0°C (32°F)
Under 0°C (32°F)
DATA LINK CONNECTOR (DLC)
6 ELC (1) is in compliance with SAEJ1962 in its installation posi-
tion, the shape of connector and pin assignment.
Serial data line (K line of ISO 9141) is used for SUZUKI scan tool
(Tech-1) to communicate with ECM, TCM, ABS control module
and Air bag SDM.
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SUZUKI serial data line is used for SUZUKI scan tool (Tech -1) to
communicate with immobilizer control module.
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-11
AMBIENT
TEMPERATURE
60 sec. or longer
Not specifiable. Select a place with
temperature higher than 0°C (32°F).
2. B+
3. Serial data line (K line of ISO 9141)
4. ECM ground
5. Body ground
6. SUZUKI serial data line
TIME TO CUT POWER TO ECM