2004 DAEWOO LACETTI Resistance vs temperature

ENGINE CONTROLS 1F – 333
DAEWOO V–121 BL4
DTC P1611 – Main Relay Low Voltage (1.4L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Disconnect the main relay.
2. Measure the resistance between main relay
terminals 85 and 86.
Does the resistance within the specified value?75~85WGo to Step 3Go to Step 6
31. Turn the ignition switch to LOCK.
2. With the test light, connected to ground, probe
the ignition feed circuit, at terminal 85 in the
relay harness connector.
Does the test light illuminate?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring harness connector.
3. With the test light, connected to ground, probe
the ignition feed circuit, at terminal 85 in the
relay harness connector.
Does the test light illuminate?–Go to Step 5Go to Step 7
5Repair a high voltage between the ECM wiring con-
nector terminal 7 and main relay terminal 85.
Is the repair complete?–Go to Step 7–
6Replace the main relay.
Is the replacement complete?–Go to Step 7–
71. 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 8Go to Step 2
8Check 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 – 335
DAEWOO V–121 BL4
DTC P1611 – Main Relay Low Voltage (1.6L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Disconnect the main relay.
2. Measure the resistance between main relay
terminals 85 and 86.
Does the resistance within the specified value?75~85WGo to Step 3Go to Step 6
31. Turn the ignition switch to LOCK.
2. With the test light, connected to ground, probe
the ignition feed circuit, at terminal 85 in the
relay harness connector.
Does the test light illuminate?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring harness connector.
3. With the test light, connected to ground, probe
the ignition feed circuit, at terminal 85 in the
relay harness connector.
Does the test light illuminate?–Go to Step 5Go to Step 7
5Repair a high voltage between the ECM wiring con-
nector terminal 7 and main relay terminal 85.
Is the repair complete?–Go to Step 7–
6Replace the main relay.
Is the replacement complete?–Go to Step 7–
71. 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 8Go to Step 2
8Check 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 – 337
DAEWOO V–121 BL4
DTC P1628 – Immobilizer No Successful Communication
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan too to the Data Link Connector
(DLC).
3. Turn the ignition ON.
4. Select IMMOBILIZER DIAGNOSIS STATUS
from the scan tool menu.
Is the communication established between the scan
tool and the immobilizer control unit?–Go to Step 3Go to
Section 9T, Im-
mobillzer Anti–
Theft System
31. Turn the ignition OFF.
2. Disconnect the Immobilizer Control Unit and
Engine Control Module (ECM) connectors.
3. Measure the resistance between terminal 7 of
immoblizer control unit and terminal 56 of the
ECM.
Is the resistance within the specified value?0WGo to Step 5Go to Step 4
4Repair an open circuit between terminal 7 of immobi-
lizer control unit and terminal 56 of the ECM.
Is the repair complete?–Go to Step 8–
5Check the terminals in immobilizer control unit and
the ECM for damages and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 6
6Replace the immobilizer control unit.
Is the repair complete?–Go to Step 8Go to Step 7
71. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 8–
81. 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 9Go to Step 2
9Check 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 – 339
DAEWOO V–121 BL4
DTC P1629 – Immobilizer Wrong Computation
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan too to the Data Link Connector
(DLC).
3. Turn the ignition ON.
4. Select IMMOBILIZER DIAGNOSIS STATUS
from the scan tool menu.
Is the communication established between the scan
tool and the immobilizer control unit?–Go to Step 3Go to
Section 9T, Im-
mobillzer Anti–
Theft System
31. Turn the ignition OFF.
2. Disconnect the Immobilizer Control Unit and
Engine Control Module (ECM) connectors.
3. Measure the resistance between terminal 7 of
immoblizer control unit and terminal 56 of the
ECM.
Is the resistance within the specified value?0WGo to Step 5Go to Step 4
4Repair an open circuit between terminal 7 of immobi-
lizer control unit and terminal 56 of the ECM.
Is the repair complete?–Go to Step 8–
5Check the terminals in immobilizer control unit and
the ECM for damages and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 6
6Replace the immobilizer control unit.
Is the repair complete?–Go to Step 8Go to Step 7
71. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 8–
81. 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 9Go to Step 2
9Check 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 – 341
DAEWOO V–121 BL4
DTC P1660 – Malfunction Indicator Lamp (MIL) High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK.
2. Disconnect the cluster wiring connector.
3. With the test light, connected to ground, probe
the ignition feed circuit, at terminal B6 in the
harness connector.
Does the resistance within the specified value?0WGo to Step 3Go to Step 6
31. Turn the ignition switch to LOCK.
2. With the test light, connected to ground, probe
the ignition feed circuit, at ECM wiring connec-
tor terminal 39.
Does the test light illuminate?–Go to Step 4–
41. Turn the ignition switch to LOCK.
2. Replace the cluster.
Is the replacement complete?–Go to Step 6–
5Repair a short to battery between the ECM wiring
connector terminal 39 and cluster wiring connector
terminal B6.
Is the repair complete?–Go to Step 6–
61. 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 7Go to Step 2
7Check 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 – 343
DAEWOO V–121 BL4
DTC P1661 – Malfunction Indicator Lamp (MIL) Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK.
2. Disconnect the cluster wiring connector.
3. With the test light, connected to ground, probe
the ignition feed circuit, at terminal B6 in the
harness connector.
Does the resistance within the specified value?0WGo to Step 3Go to Step 6
31. Turn the ignition switch to LOCK.
2. With the test light, connected to ground, probe
the ignition feed circuit, at ECM wiring connec-
tor terminal 39.
Does the test light illuminate?–Go to Step 4–
41. Turn the ignition switch to LOCK.
2. Replace the cluster.
Is the replacement complete?–Go to Step 6–
5Repair a short to ground or open between the ECM
wiring connector terminal 39 and cluster wiring con-
nector terminal B6.
Is the repair complete?–Go to Step 6–
61. 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 7Go to Step 2
7Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
applicable DTC
tableSystem OK

1F – 354IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
7With a ohmmeter connected to the ground, probe
the 5 volt reference circuit terminal M16.
Is the resistance within near the specified value.5 vGo to Step 8Go to Step 9
8Check the MAP sensor vacuum source for being
plugged or leaking.
Is a problem found?–Go to Step 10Go to Step 13
9Check the 5 volt reference circuit at terminal M16 for
a short to voltage and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 12
10Repair the vacuum source as needed.
Is the action complete?–Go to Step 14–
11Check for an open in the MAP sensor ground circuit
at terminal 1 and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 12
121. Turn the ignition switch OFF.
2. Replace the Engine Control Module (ECM).
Is the action complete?–Go to Step 14–
13Replace the MAP sensor.
Is the action complete?–Go to Step 14–
141. 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 15Go to Step 2
15Check 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 – 355
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0112
INTAKE AIR TEMPERATURE LOW VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor uses a thermistor
to control the signal voltage to the Engine Control Module
(ECM). The ECM supplies a 5 volt reference and a ground
to the sensor. When the air is cold, the resistance is high;
therefore the IAT signal voltage will be high. If the intake
air is warm, resistance is low; therefore the IAT signal volt-
age will be low.
Conditions for Setting the DTC
S IAT is less than 149°C (300°F).
S Engine run time is greater than 120 seconds.
S Vehicles speed is greater than or equal to 50 km/h
(31 mph).
S DTC P0502 is not set.
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.
S The ECM will substitute a default value for intake
air temperature. The scan tool will not show the
defaulted value.
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(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
If the vehicle is at ambient temperature, compare the IAT
sensor to the Engine Coolant Temperature (ECT) sensor.
The IAT sensor and the ECT sensor should be relatively
close to each other.
Use the Temperature vs. Resistance Values table to eval-
uate the possibility of a skewed sensor. Refer to ”Temper-
ature vs. Resistance” in this section.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
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.
4. This step simulates a DTC P0113 condition. If the
scan tool displays the specified value, the IAT sig-
nal circuit, the ECM are OK.
8. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.