1F–48 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F090
ENGINE COOLING FAN CIRCUIT CHECK
Circuit Description
The engine cooling fan circuit operates the cooling fan.
The cooling fan is controlled by the engine control mod-
ule (ECM) based on input from the coolant temperature
sensor (CTS) and the A/C ON/OFF. The ECM controls
the low speed cooling fan operation by internally ground-
ing the ECM connector terminal 39. This energizes the
low speed cooling fan relay and operates the cooling fan
at low speed. The low speed cooling fan operation is
achieved by the cooling fan resistor causing a drop in
the voltage supplied to the cooling fan. The ECM con-
trols the high speed cooling fan operation by internally
grounding the ECM connector terminal 5. This ener-
gizes the high speed cooling fan relay, bypassing the ra-
diator fan resistor. This results in high speed cooling fan
operation.
Diagnostic Aids
If the owner complained of an overheating problem, it
must be determined if the complaint was due to anactual boil over, or the engine coolant temperature
gauge indicated overheating. If the engine is over-
heating and the cooling fans are on, the cooling sys-
tem should be checked.
If the engine fuse block fuse EF15 become open
(blown) immediately after installation, inspect for a
short to ground in the wiring of the appropriate circuit.
If the fuse become open (blown) when the cooling
fans are to be turned on by the Engine Control Mod-
ule (ECM), suspect a faulty cooling fan motor.
The ECM will turn the cooling fan on at low speed
when the coolant temperature is 93C (199F). The
ECM will turn the cooling fans off when the coolant
temperature is 90C (194F).
The ECM will turn the cooling fans on at high speed
when the coolant temperature is 100C (212F). The
ECM will change the cooling fans from high speed to
low speed when the coolant temperature is 97C
(207F).
1F–52 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F010
DATA LINK CONNECTOR DIAGNOSIS
Circuit Description
The provision for communicating with the Engine Con-
trol Module (ECM) is the Data Link Connector (DLC). It
is located under the instrument panel. The DLC is used
to connect the scan tool. Battery power and ground is
supplied for the scan tool through the DLC. The Key-
word 2000 serial data circuit to the DLC allows the ECM
to communicate with the scan tool. A Universal Asyn-
chronous Receiver Transmitter (UART) serial data line
is used to communicate with the other modules such as
the Electronic Brake Control Module (EBCM), the Sup-
plemental Inflatable Restraint (SIR) system. and the In-
strument Panel Cluster.
Diagnostic Aids
Ensure that the correct application (model line, car year,
etc.) has been selected on the scan tool. If communica-
tion still cannot be established, try the scan tool onanother vehicle to ensure that the scan tool or cables
are not the cause of the condition.
An intermittent may be caused by a poor connection,
rubbed through wire insulation, or a broken wire inside
the insulation.
Any circuitry that is suspected of causing an intermittent
complaint should be thoroughly checked for the follow-
ing conditions:
Backed-out terminals.
Improper mating of terminals.
Broken locks.
Improperly formed or damaged terminals.
Poor terminal-to-wiring connection.
Physical damage to the wiring harness.
Corrosion.
ENGINE CONTROLS 1F–59
DAEWOO M-150 BL2
If the connections are OK monitor the manifold absolute
pressure (MAP) sensor signal voltage while moving re-
lated connectors and the wiring harness. If the failure isinduced, the display on the scan tool will change. This
may help to isolate the location of an intermittent mal-
function.
DTC P0107 – Manifold Absolute Pressure Sensor Low Voltage
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
1. Connect the scan tool to the data link connector
(DLC).
2. Turn the ignition switch to ON.
Does the scan tool show the manifold absolute
pressure (MAP) sensor voltage above the value
specified?
4VGo to Step 3Go to Step 4
3
1. Disconnect the vacuum line from the MAP
sensor.
2. Apply 88kPA (20in.of Hg) of vacuum to the MAP
sensor.
Does the scan tool show the MAP sensor voltage
within the value specified?
1.0–1.5V
Go to
“Diagnostic
Aids”
Go to Step 4
4
1. Turn the ignition switch to LOCK.
2. Disconnect the MAP sensor connector.
3. Turn the ignition switch to ON.
4. Measure the voltage between the MAP sensor
connector terminals A and C.
Does the voltage measure within the value
specified?
4.5–5.0VGo to Step 5Go to Step 6
5
Connect a fused jumper between the MAP sensor
connector terminals B and C.
Does the scan tool show the MAP sensor voltage
above the value specified?
4VGo to Step 11Go to Step 9
6
Measure the voltage between the MAP sensor
connector terminal A and ground.
Does the voltage measure within the value
specified?
4.5–5.0VGo to Step 7Go to Step 8
7
1. Turn the ignition switch to LOCK.
2. Check for open wires between the MAP sensor
connector terminal A and the ECM connector
terminal 78.
Is the problem found?
–
Go to Step 10Go to Step 12
8
1. Turn the ignition switch to LOCK.
2. Check for an open or short to ground in the wire
between the MAP sensor connector terminal C
and the ECM connector terminal 12.
Is the problem found ?
–
Go to Step 10Go to Step 12
9
1. Turn the ignition switch to LOCK.
2. Check for an open or short to ground in the wire
between the MAP sensor connector terminal B
and the ECM connector terminal 73.
Is the problem found ?
–
Go to Step 10Go to Step 12
1F–62 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F060
DIAGNOSTIC TROUBLE CODE (DTC) – P0108 MANIFOLD ABSOLUTE
PRESSURE SENSOR HIGH VOLTAGE
Circuit Description
The engine control module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel deliv-
ery and the ignition timing. The MAP sensor measures
the changes in the intake manifold pressure, which re-
sults from engine load (intake manifold vacuum) and the
rpm changes; and converts these into voltage outputs.
The ECM sends a 5 volt-reference voltage to the MAP
sensor. As the manifold pressure changes, the output
voltage of the MAP sensor also changes. By monitoring
the MAP sensor output voltage, the ECM knows the
manifold pressure. A low-pressure (low voltage) output
voltage will be about 1.0 to 1.5 volts at idle, while higher
pressure (high voltage) output voltage will be about 4.5
to 4.8 at wide open throttle (WOT). The MAP sensor is
metric pressure, allowing the ECM to make adjustments
for different altitudes.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
Engine speed is greater than 2,000rpm.
No throttle position sensor (TPS) fail conditions pres-
ent.
The MAP is greater than 600m bar.
A high voltage condition exists.
Action Taken when the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate.
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.A history DTC is stored.
The ECM will substitutes a fixed MAP value and use
TP to control the fuel delivery (the scan tool will not
show defaulted)
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm-up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
With the ignition ON and the engine stopped, the man-
ifold pressure is equal to atmosphere pressure and the
signal voltage will be high.
The ECM as an indication of vehicle altitude uses this
information. Comparison of this reading with a known
good vehicle with the same sensor is a good way to
check the accuracy of a suspect sensor. Readings
should be the same ±0.4volt.
If a DTC P 0108 is intermittent, refer to “manifold abso-
lute pressure check” in this Section for further diagnosis.
If the connections are OK monitor the manifold absolute
pressure(MAP) sensor signal voltage while moving re-
lated connectors and the wiring harness. If the failure is
induced, the display on the scan tool will change. This
may help to isolate the location of an intermittent mal-
function.
ENGINE CONTROLS 1F–73
DAEWOO M-150 BL2
DTC P0117 – Engine Coolant Temperature Sensor Low Voltage
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
1. Connect the scan tool to the data link connector
(DLC).
2. Run the engine until it reaches operating
temperature.
Does the scan tool show the ECT sensor reading
within the value specified?
80~110°C
(176~230°F)
Go to
“Diagnostic
Aids”
Go to Step 3
3
1. Turn the ignition switch to LOCK.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool show the IAT sensor reading
within the value specified?
≥-30°C(-22°F)Go to Step 4Go to Step 6
4
1. Jumper the ECT sensor signal circuits at terminal
A and B.
2. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?
≥120°CGo to Step 5Go to Step 6
5
1. Replace the ECT sensor.
2. Clear any DTCs from the ECM.
3. Perform the diagnostic system check.
Is the replacement complete?
–
System OK
–
6
Measure the voltage between ECT terminal A and
ground.
Does the voltage measure within the value
specified?
4.5–5.0VGo to Step 7Go to Step 8
7
1. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring connector.
3. Check for a faulty connector or terminals at the
ECT sensor connectors and ECM connectors for
short to ECM reference voltage.
Is the problem found?
–
Go to Step 9Go to Step 8
8
1. Turn the ignition switch to LOCK.
2. Repair the wire of the connector terminals as
needed.
3. Clear any DTCs from the ECM.
4. Run the engine until it reaches operating
temperature.
5. Perform the diagnostic system check.
Is the repair complete?
–
System OK
–
9
1. Replace the ECM.
2. Run the engine until it reaches operating
temperature.
3. Perform the diagnostic system check.
Is the repair complete?
–
Go to Step 10
–
10
Check if any additional DTCs are set.
Are any DTCs displaced that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
ENGINE CONTROLS 1F–75
DAEWOO M-150 BL2
DTC P0118 – Engine Coolant Temperature Sensor High Voltage
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
1. Connect the scan tool to the data link connector
(DLC).
2. Run the engine until it reaches operating
temperature.
Does the scan tool show the ECT sensor reading
within the value specified?
80~110°C
(176~230°F)
Go to
“Diagnostic
Aids”
Go to Step 3
3
1. Turn the ignition switch to LOCK.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?
≥-30°CGo to Step 4Go to Step 6
4
1. Jumper the ECT sensor signal circuits at terminal
B and A.
2. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?
≥180°C
(356°F)
Go to Step 5Go to Step 6
5
1. Replace the ECT sensor.
2. Clear any DTCs from the ECM.
3. Perform the diagnostic system check.
Is the replacement complete?
–
System OK
–
6
Measure the voltage between ECT terminal B and
ground.
Does the voltage measure within the value
specified?
4.5–5.0VGo to Step 7Go to Step 8
7
1. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring connector.
3. Check for a faulty connector or terminals at the
ECT sensor connector terminal A and the ECM
connector terminal 45 for an open or short to
battery voltage.
Is the problem found?
–
Go to Step 8Go to Step 9
8
1. Turn the ignition switch to LOCK.
2. Repair the wire of the connector terminals as
needed.
3. Clear any DTCs from the ECM.
4. Run the engine until it reaches operating
temperature.
5. Perform the diagnostic system check.
Is the repair complete?
–
System OK
–
9
1. Replace the ECM.
2. Run the engine until it reaches operating
temperature.
3. Perform the diagnostic system check.
Is the repair complete?
–
Go to Step 10
–
10
Check if any additional DTCs are set.
Are any DTCs displaced that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–106 ENGINE CONTROLS
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0171 FUEL TRIM SYSTEM TOO LEAN
System Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a Closed Loop air/
fuel metering system is used. While in Closed Loop, the
Engine Control Module (ECM) monitors the oxygen sen-
sor (O2S) signal voltage and adjusts fuel delivery based
on signal voltage. A change made to fuel delivery will be
indicated by the long and short term fuel trim values
which can be monitored with the scan tool. Ideal fuel trim
values are around 128 (0%). If the O2S signal is indicat-
ing a lean condition, the ECM will add fuel resulting in
fuel trim values above 128 (0% to 100%). If a rich condi-
tion is detected, the fuel trim values will be below 128
(0% to –100%), indicating that the ECM is reducing the
amount of fuel delivered. If exhaust emissions reach an
excessive level due to a lean or rich condition, a fuel trim
Diagnostic Trouble Code (DTC) is set.
Conditions for Setting the DTC
No intrusive tests active.
DTCs P0106, P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0125, P0131, P0132,
P0133, P0134, P0137, P0138, P0140, P0141,
P1167, P1171, P0201, P0202, P0203, P0204,
P0300, P0336, P0337, P0341, P0342, P0402,
P0404, P1404, P0405, P0406, P0443, P0506, and
P0507are not set.
The average of short term fuel trim value is greater
than or equal to 120.
Throttle Position (TP) is less than 95%.
Engine speed is between 700 and 6000 rpm.
Barometric Pressure (BARO) is greater than 92.0
kPa (10.4 psi).
Coolant temperature is between 80°C (176°F) and
11 5°C (239°F).
Manifold Absolute Pressure (MAP) is more than 90
kPa (10.2 psi).
System is in closed loop.
Adaptive index is ready.
Action Taken when the DTC Sets
Emission related.
“Armed” after two trip with a fail.
“Disarmed” after one trip with a pass.
MIL on if failure is detected in three consecutive trips.
Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Important: After repairs, use the scan tool Fuel Trim
Reset function to reset the long-term fuel trim to 128
(0%).
Fuel pressure – The system will be lean if the pres-
sure is too low. It may be necessary to monitor fuel
pressure while driving the vehicle at various road
speeds and/or loads to confirm.
Map sensor – An output that causes the ECM to
sense a lower than normal manifold pressure (high
vacuum) can cause the system to go lean. Discon-
necting the MAP sensor will allow the ECM to substi-
tute a fixed (default) value for the MAP sensor. If the
lean condition is gone when the sensor is discon-
nected, substitute a known good sensor and recheck.
Fuel contamination – Water, in even small amounts,
near the in-tank fuel pump inlet can be delivered to
the injector. The water causes a lean exhaust and
can set DTC P0171.
Check for poor O2S or MAP sensor connection at the
ECM. Inspect the harness connectors for the following
conditions:
Backed-out terminals
Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminal-to-wire connection
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the O2S display on the scan
tool while moving the connectors and the wiring harness
related to the engine harness. A change in the display
will indicate the location of the fault.
Check the brake power booster check valve for possible
leaks.
ENGINE CONTROLS 1F–109
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0172 FUEL TRIM SYSTEM TOO RICH
System Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a Closed Loop air/
fuel metering system is used. While in Closed Loop, the
Engine Control Module (ECM) monitors the oxygen sen-
sor (O2S) signal voltage and adjusts fuel delivery based
on signal voltage. A change made to fuel delivery will be
indicated by the long and short term fuel trim values
which can be monitored with the scan tool. Ideal fuel trim
values are around 128 (0%). If the O2S signal is indicat-
ing a lean condition, the ECM will add fuel resulting in
fuel trim values above 128 (0% to 100%). If a rich condi-
tion is detected, the fuel trim values will be below 128
(0% to –100%), indicating that the ECM is reducing the
amount of fuel delivered. If exhaust emissions reach an
excessive level due to a lean or rich condition, a fuel trim
Diagnostic Trouble Code (DTC) is set.
Conditions for Setting the DTC
No intrusive tests active.
DTCs P0106, P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0133,
P0134, P0137, P0138, P1167, P1171, P0300,
P0336, P0337, P0341, P0342, P0402, P0404,
P1404, P0405, P0406, P0443, P0506, and P0507are
not set.
The average of short term fuel trim value is greater
than or equal to 120.
Throttle Position (TP) is less than 95%.
Engine speed is between 700 and 6000 rpm.
Barometric Pressure (BARO) is greater than 90.0
kPa (10.4 psi).
Coolant temperature is between 80°C (176°F) and
11 5°C (239°F).
Manifold Absolute Pressure (MAP) is more than 70
kPa (10.2 psi).
System is in closed loop.
Adaptive index is ready.
Action Taken when the DTC Sets
Emission related.“Armed” after two trip with a fail.
“Disarmed” after one trip with a pass.
MIL on if failure is detected in three consecutive trips.
Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).
Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Important: After repairs, use the scan tool Fuel Trim
Reset function to reset the long-term fuel trim to 128
(0%).
Check for poor connection at the ECM. Inspect the har-
ness connectors for the following conditions:
Backed-out terminals.
Improper mating.
Broken locks.
Improperly formed.
Damaged terminals.
Poor terminal-to-wire connection.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the O2S display on the scan
tool while moving the connectors and the wiring harness
related to the engine harness. A change in the display
will indicate the location of the fault.
If a DTC P1404 is also set, check the 5 volt reference
circuits for a short to voltage.
Check for a restricted exhaust system.
A shorted 5 volt reference circuit may cause a DTC
P0172 to set. Check the 5 volt reference sensors for ab-
normal readings.