2004 DAEWOO LACETTI ignition

1F – 530IENGINE CONTROLS
DAEWOO V–121 BL4
2. Verifies the fault is present.
3. If DTC P1112 can be repeated only by duplicating
the Fail Records conditions, refer to the Tempera-
ture Vs. Resistance Value Chart. The chart may be
used to test the IAT sensor at various temperaturesto evaluate the possibility of a ”shifted” sensor that
may be shorted above or below a certain tempera-
ture. If this is the case, replace the IAT sensor.
DTC P1112 – Intake Air Temperature Intermittent Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
3. Request engine Diagnostic Trouble Code
(DTC).
Is DTC P0112 also set?–Go to
applicable DTC
tableGo to Step 3
3Check the Intake Air Temperature (IAT) signal circuit
between terminal 2 of the IAT sensor and terminal
M7 of the ECM for an intermittent short to ground
and repair as needed.
Is the repair complete?–Go to Step 4Go to
”Diagnostic
Aids”
41. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 5Go to Step 2
5Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
table System OK

1F – 532IENGINE CONTROLS
DAEWOO V–121 BL4
Engine Coolant Temperature Sensor (Temperature Vs. Resistance
Value)
°C°FOHMS°C°FOHMS
10021217715594450
801763325417280
60140667–52312300
4511 31188–15521450
35951802–30–2252700
25772796–40–40100700
Above resistance is approximate value
DTC P1114 – Engine Coolant Temperature Intermittent Low
Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
3. Request engine Diagnostic Trouble Code
(DTC).
Is Diagnostic Trouble Code (DTC) P0117 also set?–Go to
applicable DTC
tableGo to Step 3
3Check the Engine Coolant Temperature (ECT) sig-
nal circuit between terminal 1 of the ECT sensor and
terminal M28 of the ECM for an intermittent short to
ground and repair as needed.
Is the repair complete?–Go to Step 4Go to
”Diagnostic
Aids”
41. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 5Go to Step 2
5Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 534IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1115 – Engine Coolant Temperature Intermittent High
Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
3. Request engine Diagnostic Trouble Code
(DTC).
Is Diagnostic Trouble Code (DTC) P0118 set?–Go to
applicable DTC
tableGo to Step 3
3Is DTC P1111 also set?–Go to Step 7Go to Step 4
4Check for a poor sensor ground circuit terminal 2 at
the Engine Coolant Temperature (ECT) sensor and
repair as needed.
Is the repair complete?–Go to Step 9Go to Step 5
5Check for a poor sensor signal circuit between termi-
nal 1 of the ECT sensor and terminal M28 of the En-
gine Control Module (ECM) for an intermittent open
and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 6
6Check for sensor signal circuit between terminal 1 of
the ECT sensor and terminal M28 of the ECM for an
intermittent short to voltage and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 7
7Check for poor sensor ground circuit terminal M64
at the ECM and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 8
8Check for an intermittent open or a faulty splice in the
sensor ground circuit and repair as needed.
Is the repair complete?–Go to Step 9Go to
”Diagnostic
Aids”
91. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 10Go to Step 2
10Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 536IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1121 – Throttle Position Sensor Intermittent High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is Diagnostic Trouble Code (DTC) P0123 also set?–Go to
applicable DTC
tableGo to Step 3
3Check for poor sensor ground circuit terminal 1 con-
nection at the Throttle Position (TP) sensor.
Is a problem found?–Go to Step 7Go to Step 4
4Check the TP signal circuit between TP sensor con-
nector and the Engine Control Module (ECM) for an
intermittent short to voltage.
Is a problem found?–Go to Step 8Go to Step 5
5Check for a poor sensor ground terminal M64 at the
ECM.
Is a problem found?–Go to Step 7Go to Step 6
6Check for an intermittent open or faulty spice in the
sensor ground circuit.
Is a problem found?–Go to Step 8Go to
”Diagnostic
Aids”
7Repair or replace the faulty harness connector ter-
minal for sensor ground circuit.
Is the repair complete?–Go to Step 9
8Repair the intermittent open/short circuit in wiring
harness as needed.
Is the repair complete?–Go to Step 9
91. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 10Go to Step 2
10Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 538IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1122 – Throttle Position Sensor Intermittent Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is Diagnostic Trouble Code (DTC) P0123 also set?–Go to
applicable DTC
tableGo to Step 3
3Check for poor 5 volt reference circuit terminal 2 con-
nection at the Throttle Position (TP) sensor.
Is a problem found?–Step 7Step 4
4Check the TP signal circuit between TP sensor con-
nector and the Engine Control Module (ECM) for an
intermittent open or short to ground.
Is a problem found?–Go to Step 8Go to Step 5
5Check for a poor 5 volt reference circuit terminal M32
at the ECM.
Is a problem found?–Go to Step 7Go toStep 6
6Check for an intermittent open in the 5 volt reference
circuit.
Is a problem found?–Go to Step 8Go to Step 4
7Repair or replace the faulty harness connector ter-
minal for 5 volt reference circuit and/or the TP signal
circuit as needed.
Is the repair complete?–Go to Step 9–
8Repair the intermittent open/short circuit in wiring
harness as needed.
Is the repair complete?–Go to Step 9–
91. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 10Go to Step 2
10Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 539
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1133
FRONT HEATED OXYGEN SENSOR (HO2S1) TOO FEW
TRANSITION
Circuit Description
The Engine Control Module (ECM) continuously monitors
the Front Heated Oxygen Sensor (HO2S1) activity for 100
seconds. During the monitor period, the ECM counts the
number of times that the HO2S1 switches from rich to lean
and from lean to rich. With this information, a total for all
switches can be determined. If the number of switches is
too low, a Diagnostic Trouble code (DTC) P1133 will set.
The lean–to–rich and rich–to–lean are less than 15
switches.
Conditions for Setting the DTC
S HO2S1 signal switches from 0.3 to 0.6 volts and
0.6 to 0.3 volts is less than 15 times within 90sec-
onds.
S Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is greater than
70 °C (158 °F).
S System voltage is greater than 10 volts.
S Engine run time is greater than 60 seconds.
S Purge Duty Cycle (DC) is less than 20%.
S The rpm is between 1600 and 4300.
S Airflow is between 9 and 40 g/sec.S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0131, P0132, P0134, P0135,
P1167, P0171, P1171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404, and P0443 are not set.
S 2 second delay after conditions are met.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.

1F – 540IENGINE CONTROLS
DAEWOO V–121 BL4
Diagnostic Aids
DTC P1133 is most likely caused by one of the following
items:
S Fuel Pressure – The system will go rich if the fuel
pressure is too high. The ECM can compensate for
some increase. However, if it gets too high, a DTC
P1133 may set. Refer to ”Fuel System Diagnosis”
in this section.
S Leaking injector – A leaking or malfunctioning injec-
tor can cause the system to go rich.
S Manifold Absolute Pressure (MAP) sensor – An
output that causes the ECM to sense a higher than
normal manifold pressure (low vacuum) can cause
the system to go rich. Disconnecting the MAP sen-
sor will allow the ECM to set a fixed value for the
MAP sensor. Substitute a different MAP sensor if
the rich condition is gone while the sensor is dis-
connected.
S Pressure regulator – Check for a leaking fuel pres-
sure regulator diaphragm by checking for the pres-
ence of liquid fuel in the vacuum line to the pres-
sure regulator.
S Throttle Position (TP) sensor – An intermittent TP
sensor output can cause the system to go rich due
to a false indication of the engine accelerating.S HO2S1 contamination – Inspect the HO2S1 for sili-
cone contamination from fuel or improper use of
Room Temperature Vulcanizing (RTV) sealant. The
sensor may have a white powdery coating and re-
sult in a high but false voltage signal (rich exhaust
indication). The ECM will then reduce the amount
of fuel delivered to the engine causing a severe
surge or driveability problem.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Chart.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
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.
14. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.
16. If no malfunctions have been found at this point and
no additional DTCs are set, refer to ”Diagnostic
Aids” in this section for additional checks and infor-
mation.
DTC P1133 – Front Heated Oxygen Sensor (HO2S1) Too Few
Transition
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Are any additional Diagnostic Trouble Codes
(DTCs) set?–Go to
applicable DTC
tableGo to Step 3
31. Start the engine and idle at normal operating
temperature.
2. Operate the vehicle within the specified param-
eter under the Conditions For Setting the DTC.
3. Monitor the lean–to–rich transition and rich–to–
lean transition and note the number of
switches.
Does the parameter show fewer transitions than the
specified value within 90 seconds.15Go to Step 4Go to Step 18

ENGINE CONTROLS 1F – 541
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
4Visually/physically inspect for the following items:
S Front Heated Oxygen Sensor (HO2S1) is se-
curely installed.
S Corrosion on the terminals.
S Terminal tension.
S HO2S1 wiring harness for poor terminal con-
nection or damaged wiring.
Is a problem found in any of the above areas?–Go to Step 9Go to Step 5
5Check the exhaust manifold for a leak near the en-
gine and repair as needed.
Is the repair complete?–Go to Step 3Go to Step 6
61. Turn the ignition OFF.
2. Disconnect the HO2S1 connector.
3. Jumper the HO2S1 low circuit, terminal 3 to
ground.
4. Turn the ignition ON.
Does the scan tool indicate the voltage between the
specified value?400–500 mVGo to Step 7Go to Step 10
7Jumper the HO2S1 signal and low circuit terminal 4
to ground.
Does the scan tool indicate the voltage below the
specified value?200 mVGo to Step 8Go to Step 11
81. Turn the ignition OFF.
2. Replace the HO2S1.
Note : before replacing the sensor, the cause of the
contamination must be determined and corrected in
order to prevent further damage to the sensor.
Check for following:
S Fuel contamination.
S Use of improper Room Temperature Vulcaniz-
ing sealant.
S Engine oil/coolant consumption.
Is the repair complete?–Go to Step 15–
9Repair the condition as needed.
Is the repair complete?–Go to Step 15–
10Repair the HO2S1 signal circuit for a short to ground.
Is the repair complete?–Go to Step 15–
111. Remove the jumper wire.
2. Using voltmeter measure the voltage between
the HO2S1 signal circuit, terminal 4 and
ground.
Does the voltage above the specified value?407 mVGo to Step 12Go to Step 13
121. Turn the ignition OFF.
2. Disconnect the ECM connectors and check the
continuity between terminal 2 of HO2S1 and
the terminal M29 of the ECM.
3. If the circuit measures over the specified value,
repair open or poor connection as needed.
Is the repair complete?5 ΩGo to Step 15Go to Step 14