
1F – 48IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
11Compare the Engine Coolant Temperature (ECT)
with the Intake Air Temperature (IAT).
Is the ECT relatively close to the IAT?–Go to Step 12Go to ”DTC
P0118 Engine
Coolant Tem-
perature High
Voltage
121. Check if the Manifold Absolute Pressure (MAP)
sensor reading is over the specified reading.
2. Crank the engine while watching the MAP sen-
sor reading.
Does the MAP sensor read above the specified val-
ue and then change while cranking the engine?4 vGo to Step 13Go to Step 14
13Crank the engine.
Does the Crankshaft Position (CKP) Active Counter
increment while cranking?–Go to Step 16Go to Step 18
14Check the scan data for serial data.
Was serial data lost while cranking the engine?–Go to Step 15Go to ”MAP
Sensor Output
Check”
15Repair voltage loss to the engine control module
(ECM) from the ignition switch.
Is the repair complete?–System OK–
16Check for the presence of spark from all of the igni-
tion wires while cranking the engine.
Is spark present from all of the ignition wires?–Go to Step 41Go to Step 17
171. Measure the resistance of the ignition wires.
2. Replace any of the ignition wire(s) with a resist-
ance above the value specified.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?30,000 WGo to Step 3Go to Step 18
181. Turn the ignition OFF.
2. Disconnect the Crankshaft Position (CKP) sen-
sor connector.
3. Measure the voltage between the CKP connec-
tor terminals 1 and 3.
4. Repair the wiring as needed.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 19Go to Step 20
19Measure the voltage between the CKP connector
terminals 2 and 3.
Does the voltage measure near the value specified1.4 v (2.5 v)*Go to Step 26Go to Step 21
20Measure the voltage between the CKP connector
terminals 1 and ground.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 22Go to Step 23
21Measure the voltage between the CKP connector
terminals 2 and ground.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 22Go to Step 24
22Check for an open or short in the wire between the
CKP connector terminal 3 and ground.
Is the problem found?–Go to Step 25Go to Step 40
23Check for an open or short in the wire between the
CKP connector terminal 1 and the ECM connector
terminal M21
Is the problem found?–Go to Step 25Go to Step 40

ENGINE CONTROLS 1F – 59
DAEWOO V–121 BL4
Malfunction Indicator Lamp On Steady (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) system
check.
Is the check complete.–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK.
2. Install the scan tool to the Data Link Connector
(DLC).
3. Command the Malfunction Indicator Lamp
(MIL) ON and OFF.
Does the MIL turn ON and OFF when commanded?–Go to Step 7Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the Engine Control Module (ECM)
connector.
3. Turn the ignition switch to ON.
Is the MIL off?–Go to Step 6Go to Step 4
4Check the MIL control circuit for a short to ground
and repair as needed.
Is the repair complete?–Go to Step 7Go to Step 5
5Replace the instrument panel cluster. Refer to Sec-
tion 9E, Instrumentation/Driver Information.
Is the repair complete?–Go to Step 7–
6Replace the ECM.
Is the repair complete?–Go to Step 7–
71. Using the scan tool, clear the Diagnostic
Trouble Codes(DTCs).
2. Attempt to start the engine.
Does the engine start and continue to run?–Go to Step 8Go to Step 1
81. Allow the engine to idle until normal operating
temperature is reached.
2. Check if any DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 61
DAEWOO V–121 BL4
Malfunction Indicator Lamp On Steady (1.8L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) system
check.
Is the check complete.–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK.
2. Install the scan tool to the Data Link Connector
(DLC).
3. Command the Malfunction Indicator Lamp
(MIL) ON and OFF.
Does the MIL turn ON and OFF when commanded?–Go to Step 7Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the Engine Control Module (ECM)
connector.
3. Turn the ignition switch to ON.
Is the MIL off?–Go to Step 6Go to Step 4
4Check the MIL control circuit for a short to ground
and repair as needed.
Is the repair complete?–Go to Step 7Go to Step 5
5Replace the instrument panel cluster. Refer to
Section 9E, Instrumentation/Driver Information.
Is the repair complete?–Go to Step 7–
6Replace the ECM.
Is the repair complete?–Go to Step 7–
71. Using the scan tool, clear the Diagnostic
Trouble Codes(DTCs).
2. Attempt to start the engine.
Does the engine start and continue to run?–Go to Step 8Go to Step 1
81. Allow the engine to idle until normal operating
temperature is reached.
2. Check if any DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
” Applicable
DTC table”System OK

ENGINE CONTROLS 1F – 93
DAEWOO V–121 BL4
ENGINE COOLING FAN CIRCUIT CHECK – DUAL FAN
(1.4L/1.6L DOHC)
Circuit Description
The engine cooling fan circuit operates the main cooling
fan and the auxiliary cooling fan. The cooling fans are con-
trolled by the engine control module (ECM) based on in-
puts from the Engine Coolant Temperature (ECT) sensor
and the Air Conditioning Pressure (ACP) sensor. The
ECM controls the low speed cooling fan operation by inter-
nally grounding the ECM connector terminal 10. This ener-
gizes the low speed cooling fan relay and operates the
main cooling fan and the auxiliary cooling fan at low speed
as the cooling fans are connected in a series circuit. The
ECM controls the high speed cooling fan operation by in-
ternally grounding the ECM connector terminal 10 and the
ECM connector terminal 9 at the same time. This ener-
gizes the low speed cooling fan relay, the high speed cool-
ing fan relay, and the series/parallel cooling fan relay re-
sulting in high speed fan operation as the cooling fans are
now connected in a parallel circuit.
Diagnostic Aids
S If the owner complained of an overheating problem,
it must be determined if the complaint was due to
an actual boil over, or the engine coolant tempera-
ture gauge indicated overheating. If the engine is
overheating and the cooling fans are on, the cooling
system should be checked.
S If the engine fuse block fuses Ef11 become open
(blown) immediately after installation, inspect for a
short to ground in the wiring of the appropriate cir-
cuit. If the fuses become open (blown) when the
cooling fans are to be turned on by the ECM, sus-
pect a faulty cooling fan motor.
S The ECM will turn the cooling fans on at low speed
when the coolant temperature is 97°C (207°F). The
ECM will turn the cooling fans off when the coolant
temperature is 94°C(201°F).
S The ECM will turn the cooling fans on at high speed
when the coolant temperature is 101°C (214°F).
The ECM will change the cooling fans from high
speed to low speed when the coolant temperature
is 98°C (208°F).S The ECM will turn the cooling fans on at low speed
when the A/C system is on. The ECM will change
the cooling fans from low speed to high speed
when the high side A/C pressure is 1882 kPa (273
psi) then return to low speed when the high side
A/C pressure is 1448 kPa (210 psi). When the A/C
system is on, the ECM will change the cooling fans
from low to high speed when the coolant tempera-
ture reaches 117°C (244°F) then return to low
speed when the coolant temperature reaches
11 4°C (237°F).
S The cooling fan circuit can be checked quickly by
disconnecting the ECM connector 2 and grounding
the connector terminal 10. This should create low
speed cooling fan operation with the ignition ON. By
grounding the ECM connector terminals 10 and 9
and turning the ignition ON, high speed cooling fan
operation should be achieved.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
4. This step, along with step 5, checks for the ability of
the ECM to operate the cooling fans.
8. This step, along with step 9, checks for the ability of
the ECM to operate the cooling fans in response to
A/C pressure readings.
16. After confirming battery voltage and the ECM sup-
plying a ground to the coil side of the cooling fan
relay A, by jumpering connector terminals 30 and
87 it will be determined if the relay is at fault or a
wiring problem is present.
31. This step checks for the presence of battery volt-
age to the main cooling fan when the A/C is on. If
battery voltage is present and the cooling fans are
not operating, the problem is in the ground side of
the cooling fan circuit.
37. By directly grounding the ECM connector terminals
10 and 9, the main and auxiliary cooling fans
should run at high speed.
Engine Cooling Fan Circuit Check – Dual Fan (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) system
check.
Is the check completed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Check the engine fuse block fuse Ef11.
2. Replace the fuse as needed.
Is the fuse OK?–Go to Step 3Go to
”Diagnostic
Aids”

1F – 94IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
31. Check the engine fuse block fuse Ef6 and Ef8.
2. Replace the fuse as needed.
Is the fuse OK?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Turn the A/C switch OFF.
3. Connect a scan tool to the data link connector
(DLC).
4. The cooling fans should run at low speed when
the coolant temperature reaches 97°C
(207°F).
Do the cooling fans run at low speed?–Go to Step 5Go to Step 10
51. Turn the ignition OFF.
2. Turn the A/C switch OFF.
3. Connect a scan tool to the DLC.
4. Start the engine.
5. The cooling fans should run at high speed
when the coolant temperature reaches 101°C
(214°F).
Do the cooling fans run at high speed?–Go to Step 6Go to Step 33
61. Turn the ignition OFF.
2. Start the engine.
3. Turn the A/C switch ON.
Does the A/C compressor clutch engage?–Go to Step 8Go to Step 7
71. Diagnose the A/C compressor clutch circuit.
2. Repair the A/C compressor clutch circuit as
needed.
3. Start the engine.
4. Turn the A/C switch ON.
Does the A/C compressor clutch engage?–Go to Step 8–
8Do the cooling fans run at low speed?–Go to Step 9Go to Step 31
91. Turn the ignition OFF.
2. Connect the A/C pressure gauges.
3. Start the engine.
4. Turn the A/C switch ON.
5. The cooling fans should run at high speed
when the high side A/C pressure reaches 1
882 kPa (273 psi).
Do the cooling fans run at high speed?–Go to Step 10–
101. Turn the ignition OFF.
2. Connect a scan tool to the DLC.
3. The coolant temperature should be above
97°C (207°C).
4. Disconnect the main cooling fan connector.
5. Turn the ignition ON.
6. Connect a test light between the main cooling
fan connector terminal 2 and ground.
Is the test light on?–Go to Step 11Go to Step 12

ENGINE CONTROLS 1F – 95
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the ignition OFF.
2. Connect a scan tool to the DLC.
3. The coolant temperature should be above
97°C (207°C).
4. Disconnect the main cooling fan connector.
5. Connect a test light between the main cooling
fan connector terminal 1 and ground.
Is the test light on?–Go to Step 28Go to Step 17
121. Turn the ignition OFF.
2. Disconnect the cooling fan relay Low.
3. Connect a test light between the cooling fan
relay Low connector terminal 85 and ground.
4. Turn the ignition ON.
Is the test light on?–Go to Step 13Go to Step 24
131. Turn the ignition OFF.
2. Connect the cooling fan relay Low.
3. Disconnect engine control module (ECM) white
connector.
4. Connect a fused jumper between the ECM
connector terminal 10 and ground.
5. Turn the ignition ON.
Do the cooling fans run at low speed?–Go to Step 30Go to Step 14
14Check for an open wire between the low speed cool-
ing fan relay connector terminal 85 and the ECM
connector terminal 10.
Is the problem found?–Go to Step 25Go to Step 15
151. Turn the ignition OFF.
2. Disconnect the cooling fan relay Low.
3. Connect a test light between the cooling fan
relay Low connector terminal 30 and ground.
Is the test light on?–Go to Step 16Go to Step 23
16Connect a fused jumper between the cooling fan
relay Low connector terminals 30 and 87.
Do the cooling fans run at low speed?–Go to Step 26Go to Step 17
171. Disconnect the cooling fan control relay.
2. Connect a fused jumper between the cooling
fan relay Low connector terminals 30 and 87.
3. Connect a fused jumper between the cooling
fan control relay connector terminals 30 and
87.
Do the cooling fans run at low speed?–Go to Step 27Go to Step 18
18Check the wire between the cooling fan relay Low
connector terminal 87 to the main cooling fan con-
nector terminal 2 for an open.
Is the problem found?–Go to Step 22Go to Step 19
19Check the wire between the main cooling fan con-
nector terminal 1 and the cooling fan control relay
connector terminal 30 for an open.
Is the problem found?–Go to Step 22Go to Step 20

1F – 100IENGINE CONTROLS
DAEWOO V–121 BL4
ENGINE COOLING FAN CIRCUIT CHECK – DUAL FAN
(1.8L DOHC)
Circuit Description
The engine cooling fan circuit operates the main cooling
fan and the auxiliary cooling fan. The cooling fans are con-
trolled by the engine control module (ECM) based on in-
puts from the Engine Coolant Temperature (ECT) sensor
and the Air Conditioning Pressure (ACP) sensor. The
ECM controls the low speed cooling fan operation by inter-
nally grounding the ECM connector terminal K28. This en-
ergizes the low speed cooling fan relay and operates the
main cooling fan and the auxiliary cooling fan at low speed
as the cooling fans are connected in a series circuit. The
ECM controls the high speed cooling fan operation by in-
ternally grounding the ECM connector terminal K28 and
the ECM connector terminal K12 at the same time. This
energizes the low speed cooling fan relay, the high speed
cooling fan relay, and the series/parallel cooling fan relay
resulting in high speed fan operation as the cooling fans
are now connected in a parallel circuit.
Diagnostic Aids
S If the owner complained of an overheating problem,
it must be determined if the complaint was due to
an actual boil over, or the engine coolant tempera-
ture gauge indicated overheating. If the engine is
overheating and the cooling fans are on, the cooling
system should be checked.
S If the engine fuse block fuses Ef21, Ef6, Ef8 be-
come open (blown) immediately after installation,
inspect for a short to ground in the wiring of the ap-
propriate circuit. If the fuses become open (blown)
when the cooling fans are to be turned on by the
ECM, suspect a faulty cooling fan motor.
S The ECM will turn the cooling fans on at low speed
when the coolant temperature is 97°C (207°F). The
ECM will turn the cooling fans off when the coolant
temperature is 94°C(201°F).
S The ECM will turn the cooling fans on at high speed
when the coolant temperature is 101°C (214°F).
The ECM will change the cooling fans from high
speed to low speed when the coolant temperature
is 98°C (208°F).S The ECM will turn the cooling fans on at low speed
when the A/C system is on. The ECM will change
the cooling fans from low speed to high speed
when the high side A/C pressure is 1882 kPa (273
psi) then return to low speed when the high side
A/C pressure is 1448 kPa (210 psi). When the A/C
system is on, the ECM will change the cooling fans
from low to high speed when the coolant tempera-
ture reaches 117°C (244°F) then return to low
speed when the coolant temperature reaches
11 4°C (237°F).
S The cooling fan circuit can be checked quickly by
disconnecting the ECM connector 2 and grounding
the connector terminal K28. This should create low
speed cooling fan operation with the ignition ON. By
grounding the ECM connector terminals K28 and
K12 and turning the ignition ON, high speed cooling
fan operation should be achieved.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
4. This step, along with step 5, checks for the ability of
the ECM to operate the cooling fans.
8. This step, along with step 9, checks for the ability of
the ECM to operate the cooling fans in response to
A/C pressure readings.
16. After confirming battery voltage and the ECM sup-
plying a ground to the coil side of the cooling fan
relay A, by jumpering connector terminals 30 and
87 it will be determined if the relay is at fault or a
wiring problem is present.
31. This step checks for the presence of battery volt-
age to the main cooling fan when the A/C is on. If
battery voltage is present and the cooling fans are
not operating, the problem is in the ground side of
the cooling fan circuit.
37. By directly grounding the ECM connector terminals
K28 and K12, the main and auxiliary cooling fans
should run at high speed.
Engine Cooling Fan Circuit Check – Dual Fan (1.8L DOHC)
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) system
check.
Is the check completed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Check the I/P fuse block fuse F2.
2. Replace the fuse as needed.
Is the fuse OK?–Go to Step 3Go to
”Diagnostic
Aids”

ENGINE CONTROLS 1F – 101
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
31. Check the engine fuse block fuse Ef21, Ef6,
Ef8.
2. Replace the fuse as needed.
Is the fuse OK?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Turn the A/C switch OFF.
3. Connect a scan tool to the data link connector
(DLC).
4. The cooling fans should run at low speed when
the coolant temperature reaches 97°C
(207°F).
Do the cooling fans run at low speed?–Go to Step 5Go to Step 10
51. Turn the ignition OFF.
2. Turn the A/C switch OFF.
3. Connect a scan tool to the DLC.
4. Start the engine.
5. The cooling fans should run at high speed
when the coolant temperature reaches 101°C
(214°F).
Do the cooling fans run at high speed?–Go to Step 6Go to Step 33
61. Turn the ignition OFF.
2. Start the engine.
3. Turn the A/C switch ON.
Does the A/C compressor clutch engage?–Go to Step 8Go to Step 7
71. Diagnose the A/C compressor clutch circuit.
2. Repair the A/C compressor clutch circuit as
needed.
3. Start the engine.
4. Turn the A/C switch ON.
Does the A/C compressor clutch engage?–Go to Step 8–
8Do the cooling fans run at low speed?–Go to Step 9Go to Step 31
91. Turn the ignition OFF.
2. Connect the A/C pressure gauges.
3. Start the engine.
4. Turn the A/C switch ON.
5. The cooling fans should run at high speed
when the high side A/C pressure reaches 1
882 kPa (273 psi).
Do the cooling fans run at high speed?–Go to Step 10–
101. Turn the ignition OFF.
2. Connect a scan tool to the DLC.
3. The coolant temperature should be above
97°C (207°C).
4. Disconnect the main cooling fan connector.
5. Turn the ignition ON.
6. Connect a test light between the main cooling
fan connector terminal 2 and ground.
Is the test light on?–Go to Step 11Go to Step 12