1A-42 Engine Control System
• Reading serial data
Verifying Vehicle Repair
Verification of vehicle repair will be more
comprehensive for vehicles with on-board diagnostic
(OBD) system diagnostic. Following a repair, the
technician should perform the following steps:
1. Review and record DTC diagnosed or Tech 2 data
or both.
2. Clear DTC(s).
3. Operate the vehicle within the conditioned
described by Tech 2 data.
4. Monitor the DTC status information for the specific
DTC that has been diagnosed until the ECM
performs the diagnostic test associated with that
DTC.
Following these steps is very important in verifying
repairs OBD systems. Failure to follow these steps
could result in unnecessary repairs.
Diagnostic Trouble Code (DTC)
Whenever the starter switch is turned on, the ECM
executes self-testing for almost wirings and
components and, when detects a system fault, stores it
and enables backup control according to the DTC set.
When a fault occurs that will affect the running, the
ECM turns on the CHECK ENGINE lamp (MIL) in the
meter panel or blinks the exhaust indicator lamp to
inform the driver of the fact.
Reading Diagnostic Trouble Codes
Current and past DTCs stored to the ECM can be
visualized in the form of blinking CHECK ENGINE lamp
(MIL) when the DLC (data link connector) is shorted. To
this end, provide the following steps.
1. Turn on the starter switch and check the CHECK
ENGINE lamp (MIL) is turned on. (Bulb check)
2. Keep the starter switch turned on and the engine
turned off.
3. Short pins 6 and 4 on the DLC. The DLC is a black
16-way connector and located at the lower right
corner of the instrument panel.
4. On the CHECK ENGINE lamp (MIL), read the
number of blinks.
5. Identify the DTC from the DTC Chart.
Diagnostic Trouble Codes Not Stored
Code 12 that shows initiation of indication is repeatedly
displayed.
LNW21ASH001801
8
7
6
5
4
3
2
1
16
15
14
13
12
11
10
9
LNW21ASH000201
LNW21ASH000301
8
7
6
5
4
3
2
1
16
15
14
13
12
11
10
9
Summary of Contents for 4HL1
Page 267: ...No LG4HL WE 0229DOM...
