Precaution In Diagnosing Trouble - Suzuki 2000 Grand Vitara SQ625 Service Manual

6-1-14 ENGINE (H25 ENGINE)

PRECAUTION IN DIAGNOSING TROUBLE

D 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. Such disconnection will
erase memorized information in ECM (PCM) memory.
D Diagnostic information stored in ECM (PCM) memory can be
cleared as well as checked by using SUZUKI scan tool (Tech-1)
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.
D Priorities for diagnosing troubles (vehicle without monitor con-
nector).
If two or more diagnostic trouble codes (DTCs) are stored, pro-
ceed to the flow table of the DTC which was 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.
1. Diagnostic trouble codes (DTCs) other than DTC P0171/
P0172/P0174/P0175 (Fuel system too lean/too rich), DTC
P0300/P0301/P0302/P0303/P0304/P0305/P0306 (Misfire de-
tected) and DTC P0400 (EGR flow malfunction)
2. DTC P0171/P0172/P0174/P0175 (Fuel system too lean/too
rich) and DTC P0400 (EGR flow malfunction)
3. DTC P0300/P0301/P0302/P0303/P0304/P0305/P0306 (Mis-
fire detected)
D Be sure to read "PRECAUTIONS FOR ELECTRICAL CIRCUIT
SERVICE" in "GENERAL INFORMATION" section before in-
spection and observe what is written there.
D ECM (PCM) Replacement
When substituting a known-good ECM (PCM), check for following
conditions. Neglecting this check may cause damage to a known-
good ECM (PCM).
– Resistance value of all relays, actuators is as specified re-
spectively.
– MAP sensor and TP sensor are in good condition and none of
power circuits of these sensors is shorted to ground.