Daewoo Nubira User Manual page 517

1F – 12IENGINE CONTROLS
Knock Present
The KS Noise Channel indicates when the PCM/ECM
etects the KS signal. The PCM/ECM should display O at
idle.
Long Term FT
The Long Term Fuel Trim (FT) is derived from the short
term fuel trim value. The Long Term FT is used for the long
term correction of the fuel delivery. A value of 128 counts
(0%) indicates that the fuel delivery requires no com-
pensation in order to maintain a 14.7:1 air to fuel ratio. A
value below 128 counts means that the fuel system is too
rich and the fuel delivery is being reduced. The PCM/ECM
is decreasing the injector pulse width. A value above 128
counts indicates that a lean condition exists for which the
PCM/ECM is compensating.
Long Term FT Average
Long Term FT Average is derived from the long term fuel
trim from all of the cells. The PCM/ECM then takes all of
the values and then creates one average value.
Loop Status
The Closed Loop is displayed indicating that the PCM/
ECM is controlling the fuel delivery according to the Oxy-
gen Sensor (O2S 1) voltage as close to an air/fuel ratio of
14.7 to 1 as possible.
MAP
The MAP sensor measures the change in the intake man-
ifold pressure which results from engine load and speed
changes. As the intake manifold pressure increases, the
air density in the intake also increases and the additional
fuel is required.
Misfire Current #1–4
Indicates the number of current misfires that are present
in the indicated cylinder. Increments only when misfire is
current.
Misfire History #1–4
Indicates the number of misfires that have occurred after
195 current misfires have been counted. The current mis-
fire counter will add its misfires to the history misfire count-
er after 195 total misfires have taken place. If 1 cylinder is
misfiring, the misfiring current counter will have 195 mis-
fires counted before adding to its history counter. If 2 cylin-
ders are misfiring, the misfiring current counter will add to
their history counters after 97 misfires. The counter incre-
ments only after a misfire diagnostic trouble code (DTC)
has been set.
Oxygen Sensor Bank 1 Sensor 1
The pre–converter Oxygen Sensor (O2S 1) reading repre-
sents the exhaust oxygen sensor output voltage. This volt-
age will fluctuate constantly between 100 mv (lean ex-
haust) and 900 mv (rich exhaust) when the system is
operating in a Closed Loop.
Oxygen Sensor Bank 1 Sensor 2
The post–converter Heated Oxygen Sensor (HO2S 2)
represents the exhaust oxygen output voltage past the
catalytic converter. This voltage remains inactive, or the
voltage will appear lazy within a range of 100 mv (lean ex-
haust) and 900 mv (rich exhaust) when operating in a
Closed Loop.
Short Term FT
The Short Term FT represents a short term correction to
fuel delivery by the PCM/ECM in response to the amount
of time the oxygen sensor voltage spends above or below
the 450 mv threshold. If the oxygen sensor has mainly
been below 450 mv, indicating a lean air/fuel mixture, short
term fuel trim will increase to tell the PCM/ECM to add fuel.
If the oxygen sensor voltage stays mainly above the
threshold, the PCM/ECM will reduce fuel delivery to com-
pensate for the indicated rich condition.
Short Term FT Average
The Short Term FT Average is derived from the short term
fuel trim from all of the cells. The PCM/ECM takes all of the
values and then creates one average value.
Spark
This is a display of the spark advance Ignition Coil (IC) cal-
culation which the PCM/ECM is programming in the igni-
tion system. It computes the desired spark advance using
data such as engine temperature, rpm, engine load, ve-
hicle speed and operating mode.
TCC Brake Switch
When the brake pedal is applied, the Torque Converter
Clutch (TCC) brake switch sends a signal to the PCM/
ECM to disengage the TCC and disable the cruise control.
Total Misfire Current Counter
Indicates the total number of misfires that have been de-
tected in all the cylinders after 100 engine cycles. One
cycle equals one complete 4 stroke cycle. The total misfire
only increments during the steady state cruise conditions.
TP Angle
From the Throttle Position (TP) Sensor voltage input, the
PCM/ECM computes the TP. The TP Angle will auto zero
to 0% at idle (TP voltage below 0.90 volts). The TP Angle
will read 100% at WOT.
TP Sensor
The PCM/ECM uses the TP Sensor in order to determine
the amount of the throttle demanded by the vehicle's oper-
ator. The TP Sensor reads between 0.36–0.96 volts at idle
to above 4 volts at WOT.
Vehicle Speed
The vehicle speed sensor signal is converted into mph or
km/h for display. The vehicle speed output from the PCM/
ECM is 4000 pulses per mile. The scan tool uses the class
2 serial data from the PCM/ECM to obtain vehicle speed,
DAEWOO V–121 BL4