Daewoo MATIZ, Service Manual

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ENGINE CONTROLS 1F – 15
DAEWOO M-150 BL2
made to enter DTC numbers for tests which the diag-
nostic executive does not recognize, the requested in-
formation will not be displayed correctly and the scan
tool may display an error message. The same applies to
using the DTC trigger option in the Snapshot mode. If an
invalid DTC is entered, the scan tool will not trigger.
Failed Last Test
This message display indicates that the last diagnostic
test failed for the selected DTC. For type A, B and E
DTCs, this message will be displayed during subse-
quent ignition cycles until the test passes or DTCs are
cleared. For type C and type D DTCs, this message will
clear when the ignition is cycled.
Failed Since Clear
This message display indicates that the DTC has failed
at least once within the last 40 warm-up cycles since the
last time DTCs were cleared.
Failed This Ig. (Failed This Ignition)
This message display indicates that the diagnostic test
has failed at least once during the current ignition cycle.
This message will clear when DTCs are cleared or the
ignition is cycled.
History DTC
This message display indicates that the DTC has been
stored in memory as a valid fault. A DTC displayed as a
History fault may not mean that the fault is no longer
present. The history description means that all the con-
ditions necessary for reporting a fault have been met
(maybe even currently), and the information was stored
in the control module memory.
MIL Requested
This message display indicates that the DTC is currently
causing the MIL to be turned ON. Remember that only
type A B and E DTCs can request the MIL. The MIL re-
quest cannot be used to determine if the DTC fault con-
ditions are currently being experienced. This is because
the diagnostic executive will require up to three trips dur-
ing which the diagnostic test passes to turn OFF the
MIL.
Not Run Since CI (Not Run Since Cleared)
This message display indicates that the selected diag-
nostic test has not run since the last time DTCs were
cleared. Therefore, the diagnostic test status (passing
or failing) is unknown. After DTCs are cleared, this mes-
sage will continue to be displayed until the diagnostic
test runs.
Not Run This Ig. (Not Run This Ignition)
This message display indicates that the selected diag-
nostic test has not run during this ignition cycle.
Test Ran and Passed
This message display indicates that the selected diag-
nostic test has done the following:
D
Passed the last test.
D
Run and passed during this ignition cycle.
D
Run and passed since DTCs were last cleared.
If the indicated status of the vehicle is “Test Ran and
Passed” after a repair verification, the vehicle is ready to
be released to the customer.
If the indicated status of the vehicle is “Failed This Igni-
tion” after a repair verification, then the repair is incom-
plete and further diagnosis is required.
Prior to repairing a vehicle, status information can be
used to evaluate the state of the diagnostic test, and to
help identify an intermittent problem. The technician can
conclude that although the MIL is illuminated, the fault
condition that caused the code to set is not present. An
intermittent condition must be the cause.
PRIMARY SYSTEM-BASED
DIAGNOSTICS
There are primary system-based diagnostics which
evaluate the system operation and its effect on vehicle
emissions. The primary system-based diagnostics are
listed below with a brief description of the diagnostic
function:
Oxygen Sensor Diagnosis
The fuel control oxygen sensor (O2S) is diagnosed for
the following conditions:
D
Few switch count (rich to lean or lean to rich).
D
Slow response (average transient time lean to rich or
rich to lean).
D
Response time ratio (ratio of average transient time
rich(lean) to lean(rich)).
D
Inactive signal (output steady at bias voltage approxi-
mately 450 mV).
D
Signal fixed high.
D
Signal fixed low.
The catalyst monitor heated oxygen sensor (HO2S) is
diagnosed for the following conditions:
D
Heater performance (current during IGN on).
D
Signal fixed low during steady state conditions or
power enrichment (hard acceleration when a rich mix-
ture should be indicated).
D
Signal fixed high during steady state conditions or de-
celeration mode (deceleration when a lean mixture
should be indicated).
D
Inactive sensor (output steady at approx. 438 mV).
If the O2S pigtail wiring, connector or terminal are dam-
aged, the entire O2S assembly must be replaced. Do
not attempt to repair the wiring, connector or terminals.
In order for the sensor to function properly, it must have
clean reference air provided to it. This clean air refer-
ence is obtained by way of the O2S wire(s). Any attempt
to repair the wires, connector or terminals could result in