Daewoo CIELO EURO III Manual page 503

Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
D The MIL will turn off after three (four –
1.5L SOHC) consecutive ignition cycles in which the
diagnostic runs without a fault.
D A history DTC will clear after 40 consecutive warm up
cycles without a fault.
D DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Inspect the IAC valve electrical connection for proper
mating.
Inspect the wiring harness for damage.
Inspect throttle stop screw for signs of tampering.
Inspect throttle linkage for signs of binding or excessive
wear.
A slow, or unstable idle may be caused by one of the fol-
lowing conditions:
D Fuel system too rich or too lean.
D Foreign material in the throttle body bore or in the air
induction system.
D A leaking or restricted intake manifold.
D Excessive engine overloading. Check for seized pul-
leys, pumps, or motors on the accessory drive,
D Overweight engine oil.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Table.
1. The On-Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
DAEWOO T-154 BL2,3
ENGINE CONTROLS 1F – 333
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. A normally operating IAC system will be able to be
extended and retracted by a scan tool and change
the engine idle rpm. Valve movement is verified by
an engine rpm change.
3. If the scan tool was able to command the IAC valve
smoothly, a malfunction may still exist internally
within the IAC valve. This can be checked by check-
ing the IAC valves internal resistance.
5. The IAC circuits always have ground or voltage sig-
nals on them in pairs. If the test light illuminates on
more or less than 2 terminals, 1 of the circuits is
shorted to voltage or open.
6. The IAC circuits always have ground or voltage sig-
nals on them in pairs. If the test light illuminates on
more or less than 2 terminals, 1 of the circuits is
shorted to ground or open
8. The IAC circuits are constantly switched between
ground and voltage so the test light should blink on
all circuits when connected to ground.
10. Any circuitry, that is suspected as causing the inter-
mittent complaint, should be thoroughly checked for
backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals,
poor terminal-to-wiring connections or physical
damage to the wiring harness.
12. A test light that remains ON constantly indicates that
the circuit is shorted to voltage.
14. The replacement ECM must be repro-
grammed. Refer to the latest Techline procedure for
ECM reprogramming.
16. If no malfunctions have been found at this point and
no additional DTCs were set, refer to "Diagnostic
Aids" in this section for additional checks and infor-
mation.