ENGINE CONTROLS 1F – 47
DAEWOO V–121 BL4
MALFUNCTION INDICATOR LAMP ON STEADY
Circuit Description
When the ignition is turned ON, the Malfunction Indicator
Lamp (MIL) will momentarily flash on and off, then it will re-
main on until the engine is running if no Diagnostic Trouble
Codes (DTCs) are stored. Battery voltage is supplied
through the ignition switch directly to the MIL telltale. The
powertrain control module (PCM)/engine control module
(ECM) controls the MIL by providing a ground path
through the MIL control circuit to turn on the MIL.
Test Description
Number(s) below refer to the step number(s) on the diag-
nostic table.
1. The On–Board Diagnostic (OBD II) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on then scan tool, if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is stored
in the scan tool for later reference.
2. When the ignition is turned ON, the MIL should mo-
mentarily flash on and off, then remain on until the
engine is running or if an emission related DTC is
stored.
3. This step checks the ability of the PCM/ECM to
control the MIL. The scan tool has the ability to
command the MIL on and off.
5. A shorted MIL circuit can be diagnosed with a scan
tool.
7. The replacement PCM/ECM must be repro-
grammed. Refer to the latest Techline information
for reprogramming procedures.
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