Suzuki 2000 Grand Vitara SQ416, Service Manual

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YH4
GRAND
VITARA
(1st)
1st, 2nd or 3rd in parentheses here represents which
position in the order the malfunction is detected.
ENGINE DIAGNOSIS (G16 / J20 ENGINES) 6-7
Warm-Up Cycle
A “warm-up cycle” means sufficient vehicle operation such that the
coolant temperature has risen by at least 22
_
C (40
_
F) from engine
starting and reaches a minimum temperature of 70
_
C (160
_
F).
Driving Cycle
A “driving cycle” consists of two parts, engine startup and engine
shutoff.
2 Driving Cycle Detection Logic
The malfunction detected in the first driving cycle is stored in ECM
(PCM) memory (in the form of pending DTC) but the malfunction in-
dicator lamp does not light at this time. It lights up at the second
detection of same malfunction also in the next driving cycle.
Pending Diagnostic Trouble Code (DTC)
Pending DTC means a DTC detected and stored temporarily at 1
driving cycle of the DTC which is detected in the 2 driving cycle
detection logic.
Freeze Frame Data
ECM (PCM) stores the engine and driving conditions (in the form
of data as shown at the left) at the moment of the detection of a mal-
function in its memory. This data is called “Freeze frame data”.
Therefore, it is possible to know engine and driving conditions (e.g.,
whether the engine was warm or not, where the vehicle was running
or stopped, where air/fuel mixture was lean or rich) when a malfunc-
tion was detected by checking the freeze frame data. Also, ECM
(PCM) has a function to store each freeze frame data for three dif-
ferent malfunctions in the order as the malfunction is detected. Uti-
lizing this function, it is possible to know the order of malfunctions
that have been detected. Its use is helpful when rechecking or diag-
nosing a trouble.
Priority of freeze frame data:
ECM (PCM) has 4 frames where the freeze frame data can be
stored. The first frame stores the freeze frame data of the malfunc-
tion which was detected first. However, the freeze frame data
stored in this frame is updated according to the priority described
below. (If malfunction as described in the upper square “1” below
is detected while the freeze frame data in the lower square “2” has
been stored, the freeze frame data “2” will be updated by the freeze
frame data “1”.)
PRIORITY FREEZE FRAME DATA IN FRAME 1
1
Freeze frame data at initial detection of
malfunction among misfire detected
(P0300
P0304), fuel system too lean
(P0171) and fuel system too rich (P0172).
2
Freeze frame data when a malfunction
other than those in “1” above is detected.
In the 2nd through the 4th frames, the freeze frame data of each
malfunction is stored in the order as the malfunction is detected.
These data are not updated.
Shown in the table below are examples of how freeze frame data
are stored when two or more malfunctions are detected.