Page 701 - Workshop Manual - Tunland (2017)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-15

DIAGNOSIS SYSTEM 04

1 . Failures of engine electric control system may be divided into 2 types:
(a) One type is to light up the MIL lamp (OBD failure indicating lamp), indicating the
emission control failure and limp mode of the system. Once the MIL lamp of instrument
goes on, immediate treatment shall be performed as per relevant national laws and
regulations. Otherwise the system may limit the fuel injection and speed of the engine
so that the normal use of vehicle may be affected.
(b) The other type may have the SVS failure indicating lamp lit up, which indicates that
the electric control system develops a fault that shall be repaired in time.
(c) For the both types of failures, failure diagnostic apparatus or special equipment
designed for corresponding functions shall be used to conduct corresponding checks.
2 . Light-up of SVS lamp and MIL lamp are under the control of ECM. Detailed
light-up of SVS and MIL lamps before and after startup is described below:
• When the system is failure free and the ignition switch is set to its ON position,
the MIL lamp and the SVS lamp will go on (system self-check); neither the SVS
lamp nor MIL lamp goes on after startup and engine stall.
• When the system is faulty and the ignition switch is set to its ON position, the
MIL lamp and the SVS lamp will constantly go on (system self-check); After
startup, if the SVS lamp is defined as - ON mode in the failure categories, the
SVS lamp may constantly go on when the SVS lamp -ON conditions are
satisfied.If the MIL lamp is defined as - ON mode in the failure categories, the
MIL lamp will constantly go on when the MIL lamp- ON conditions are satisfied.
When the ignition switch is set to it OFF position after engine stall, the both
lamps go out when the AFTERRUN process (90s at most) expires.
3 . To diagnose and exclude an engine failure that might relate to the electric-control
fuel injection system, it is required to judge whether or not the failure relates to
the electric-control fuel injection system firstly. If the engine is faulty while the
failure indicating lamp does not go on, the failure may not relate to the electric
control system in most cases.
(a) Relevant failure code record and data stored in the ECM, which are related to the
sensors and actuators, may be read by diagnostic apparatus KT600. In addition,
actuator may be compulsorily driven by the diagnostic apparatus under specific
conditions.
(b) DLC- data interlink connector.

Terminal no. Name

3 CAN2 H
4 Ground

5 Ground
6 CAN-H

9 LIN1
11 CAN2-L

14 CAN_L