Suzuki Engine 2002 GRAND VITARA SQ625, Service Manual

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ENGINE GENERAL INFORMATION AND DIAGNOSIS (G16/J20 ENGINES) 6-13
DATA LINK CONNECTOR (DLC)
DLC (1) is in compliance with SAEJ1962 in its installation posi-
tion, the shape of connector and pin assignment.
K line of ISO 9141 (4) is used for SUZUKI scan tool to communi-
cate with ECM, Air Bag SDM and ABS control module.
SUZUKI serial data line (3) is used for SUZUKI scan tool to com-
municate with an electronic control unit (Immobilizer control mod-
ule).
Precaution in Diagnosing Trouble
• Don’t disconnect couplers from ECM (PCM), battery cable from battery, ECM (PCM) ground wire harness
from engine or main fuse before confirming diagnostic information (DTC, freeze frame data, etc.) stored in
ECM (PCM) memory.
• Diagnostic information stored in ECM (PCM) memory can be cleared as well as checked by using SUZUKI
scan tool or generic scan tool. 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 without monitor connector)
If two or more diagnostic trouble codes (DTCs) are stored, proceed to the flow table of the DTC which has
detected earliest in the order and follow the instruction in that table.
If no instructions are given, troubleshoot diagnostic trouble codes according to the following priorities.
– Diagnostic trouble codes other than fuel trim malfunction (DTC P0171, P0172), EGR (DTC P0400), and
misfire (DTC P0300 – P0304).
– Fuel trim malfunction (DTC P0171, P0172) and EGR (DTC P0400).
– Misfire (DTC P0300 – P0304)
• Be sure to read “Precautions for Electrical Circuit Service” in Section 0A before inspection and observe what
is written there.
• ECM (PCM) replacement or substitution
When substituting a known-good ECM, check for following conditions. Neglecting this check may cause
damage to known-good ECM.
– Resistance value of all relays, actuators is as specified respectively.
– MAF sensor, MAP sensor and TP sensor are in good condition and none of power circuits of these sen-
sors is shorted to ground.
2. B+
5. Body ground
6. ECM (PCM) ground