Engine Diagnosis; On-Board Diagnostic System - Suzuki Grand Vitara XL-7 Service Manual

6-6 ENGINE DIAGNOSIS (RHZ ENGINE WITH SINGLE-CONNECTOR ECM)
GENERAL DESCRIPTION
This vehicle is equipped with an engine and emission control system which are under control of ECM (PCM).
The engine and emission control system in this vehicle are controlled by ECM (PCM). ECM (PCM) 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" and each item in "Precaution in Diagnosing Trouble" and execute diagnosis ac-
cording to "ENGINE DIAGNOSTIC FLOW TABLE".
There is a close relationship between the engine mechanical, engine cooling 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 this flow table.
or
3
1. Malfunction indicator lamp (MIL)
2. Data link connector (DLC)
3. SUZUKI scan tool (TECH 1)

ENGINE DIAGNOSIS

ON-BOARD DIAGNOSTIC SYSTEM

ECM (PCM) in this vehicle has the following functions.
1
D When the ignition switch is turned ON with the engine at a stop,
MIL turns ON to check the bulb of the malfunction indicator lamp
(MIL).
D When ECM (PCM) detects a malfunction which gives an adverse
effect to vehicle emission while the engine is running, it makes the
malfunction indicator lamp in the meter cluster of the instrument
panel turn ON and stores the malfunction area in its memory.
D As a condition for detecting a malfunction in some areas in the
system being monitored by ECM (PCM) and turning ON the mal-
function indicator lamp due to that malfunction, 2 driving cycles
detection logic is adopted to prevent erroneous detection.
D When a malfunction is detected, engine and driving conditions
then are stored in ECM (PCM) memory as freeze frame data. (For
the details, refer to description on Freeze frame data.)
D It is possible to communicate by using not only SUZUKI scan tool
but also generic scan tool. (Diagnostic information can be ac-
cessed by using a scan tool.)
2