1F – 30IENGINE CONTROLS
DAEWOO V–121 BL4
On–Board Diagnostic (OBD II) System Check
Step Action Value(s) Yes No
1
1. Ignition ON, engine OFF.
2. Observe the malfunction indicator lamp (MIL)
Is the MIL on?
Go to Step 2 Go to ”No Mal-
function Indica-
tor Lamp”
2
1. Ignition OFF.
2. Install the scan tool.
3. Ignition ON.
4. Attempt to display the powertrain control mod-
ule (PCM)/engine control module (ECM) en-
gine data with the scan tool.
Does the scan tool display the PCM/ECM engine
data?
Go to Step 3 Go to Step 8
3
1. Using the scan tool output test function, select
MIL dash lamp control and command the MIL
OFF.
2. Observe the MIL.
Does the MIL turn OFF?
Go to Step 4 Go to ”Malfunc-
tion Indicator
Lamp on
Steady”
4 Attempt to start the engine.
Does the engine start and continue to run?
Go to Step 5 Go to ”Engine
Cranks But Will
Not Run”
5 Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes (DTCs) stored?
Go to Step 6 Go to Step 7
6 Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0712, P1392.
Are two or more of the following DTCs stored?
Go to ”Multiple
PCM/ECM In-
formation Sen-
sor DTCs Set”
Go to applica-
ble DTC table
7 Compare the PCM/ECM data values displayed on
the scan tool to the typical engine scan data values.
Are the displayed values normal or close to the typi-
cal values?
Go to ”PCM/
ECM Output
Diagnosis”
Go to indicated
component
system check
8
1. Ignition OFF, disconnect the PCM/ECM.
2. Ignition ON, engine OFF.
3. Check the class 2 data circuit for an open,
short to ground, or short to voltage. Also,
check the Data Link Connector (DLC) ignition
feed circuit for an open or short to ground and
the DLC ground circuits for an open.
Is a problem found?
Go to Step 9 Go to Step 10
9 Repair the open, short to ground or short to voltage
in the class 2 data circuit or the DLC ignition feed cir-
cuit or DLC ground circuts.
Is the repair complete?
System OK
10
1. Attempt to reprogram the PCM/ECM.
2. Attempt to display the PCM/ECM data with the
scan tool.
Does the scan tool display PCM/ECM engine data?
Go to Step 2 Go to Step 11
11 Replace the PCM/ECM.
Is the repair complete?
System OK
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