Engine Diagnosis General Description; On-Board Diagnostic System Description - Suzuki 2006 SX4 Service Manual

Engine Diagnosis General Description

NOTE
There are two types of OBD system
depending on the vehicle specification.
For identification, refer to "Precaution on On-
Board Diagnostic (OBD) System".
The engine and emission control systems in this vehicle
are controlled by ECM. ECM has an On-Board
Diagnostic system which detects a malfunction in this
system and abnormality of those parts that influence the
engine exhaust emission. When diagnosing engine
troubles, be sure to have full understanding of the outline
of "On-Board Diagnostic System Description" and each
item in "Precautions in Diagnosing Trouble" and execute
diagnosis according to "Engine and Emission Control
System Check".
There is a close relationship between the engine
mechanical, engine cooling system, ignition system,
exhaust system, etc. and the engine and emission
control system in their structure and operation. In case of
an engine trouble, even when the malfunction indicator
lamp (MIL) doesn't turn ON, it should be diagnosed
according to "Engine and Emission Control System
Check".

On-Board Diagnostic System Description

NOTE
There are two types of OBD system
depending on the vehicle specification.
For identification, refer to "Precaution on On-
Board Diagnostic (OBD) System".
Euro OBD model
ECM in this vehicle has the following functions.
• When the ignition switch is turned ON with the engine
at a stop, malfunction indicator lamp (MIL) (1) turns
ON to check the MIL (1) and its circuit.
• When ECM detects a malfunction which gives an
adverse effect to vehicle emission while the engine is
running, it makes MIL in the meter cluster of the
instrument panel turn ON or flash (flashing only when
detecting a misfire which can cause damage to the
catalyst) and stores the malfunction area in its
memory.
(If it detects that continuously 3 driving cycles are
normal after detecting a malfunction, however, it
makes MIL turn OFF although DTC stored in its
memory will remain.)
• As a condition for detecting a malfunction in some
areas in the system being monitored by ECM and
turning on MIL due to that malfunction, 2 driving cycle
detection logic is adopted to prevent erroneous
detection.
Engine General Information and Diagnosis:
• When a malfunction is detected, engine and driving
S6RW0C1101002 conditions are stored in ECM memory as freeze frame
data. (For the details, refer to description on "Freeze
Frame Data: ".)
• It is possible to communicate via DLC (data link
connector) (3) by using not only SUZUKI scan tool
(SUZUKI-SDT) (2) but also CAN communication OBD
generic scan tool. (Diagnostic information can be
accessed by using a scan tool.)
S6RW0C1101003
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 engine startup, and engine
shutoff.
2 Driving Cycle Detection Logic
The malfunction detected in the first driving cycle is
stored in ECM memory (in the form of pending DTC and
freeze frame data) but the MIL does not light at this time.
It lights up at the second detection of same malfunction
also in the next driving cycle.
Pending 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.
1
3
2
1A-5
I7RW01110012-01