Suzuki Engine 2002 GRAND VITARA SQ625, Service Manual

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6-10 ENGINE GENERAL INFORMATION AND DIAGNOSIS (G16/J20 ENGINES)
FREEZE FRAME DATE
ECM (PCM) stores the engine and driving conditions (in the form
of data as shown at the figure) at the moment of the detection of a
malfunction 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 malfunction was detected by checking the freeze frame data.
Also, ECM (PCM) has a function to store each freeze frame data
for three different malfunctions in the order as the malfunction is
detected. Utilizing this function, it is possible to know the order of
malfunctions that have been detected. Its use is helpful when
rechecking or diagnosing 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 mal-
function 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”.)
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.
[A] : An Example of Freeze Frame Data
[B] : 1st, 2nd or 3rd in parentheses here represents which position in the order the mal-
function is detected.
PRIORITY FREEZE FRAME DATA IN FRAME 1
1
Freeze frame data at initial detection of malfunc-
tion 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.