1F–254 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F310
DIAGNOSTIC TROUBLE CODE (DTC) – P1537 A/C COMPRESSOR RELAY HIGH
V O LTA G E
Circuit Description
The A/C system uses an A/C refrigerant pressure sen-
sor mounted in the high pressure side of the A/C refrig-
erant system to monitor A/C refrigerant pressure. The
engine control module (ECM) uses this information to
turn ON the engine coolant fans when the A/C refriger-
ant pressure is high and to keep the compressor disen-
gaged when A/C refrigerant pressure is excessively high
or low.
Conditions for Setting the DTC
A/C compressor relay circuit short to battery.
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
The ECM will store conditions which were present
when the DTC was set as Failure Records data only.
This information will not be stored in the Freeze
Frame data.Conditions for Clearing the MIL/DTC
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
Inspect harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire connec-
tion at the ECM.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the A/C pressure display on
the scan tool while moving the connectors and wiring
harnesses related to the ACP sensor. A change in the
A/C pressure display will indicate the location of the
fault.
If DTC P1537 cannot be duplicated, reviewing the Fail
Records vehicle mileage since the diagnostic test last
failed may help determine how often the condition that
caused the DTC to set occurs. This may assist in diag-
nosing the condition.
1F–256 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F310
DIAGNOSTIC TROUBLE CODE (DTC) – P1538 A/C COMPRESSOR RELAY LOW
V O LTA G E
Circuit Description
The A/C system uses an A/C refrigerant pressure sen-
sor mounted in the high pressure side of the A/C refrig-
erant system to monitor A/C refrigerant pressure. The
engine control module (ECM) uses this information to
turn ON the engine coolant fans when the A/C refriger-
ant pressure is high and to keep the compressor disen-
gaged when A/C refrigerant pressure is excessively high
or low.
Conditions for Setting the DTC
A/C compressor relay circuit short to ground or open.
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
The ECM will store conditions which were present
when the DTC was set as Failure Records data only.
This information will not be stored in the Freeze
Frame data.Conditions for Clearing the MIL/DTC
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
Inspect harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire connec-
tion at the ECM.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the A/C pressure display on
the scan tool while moving the connectors and wiring
harnesses related to the ACP sensor. A change in the
A/C pressure display will indicate the location of the
fault.
If DTC P1538 cannot be duplicated, reviewing the Fail
Records vehicle mileage since the diagnostic test last
failed may help determine how often the condition that
caused the DTC to set occurs. This may assist in diag-
nosing the condition.
ENGINE CONTROLS 1F–263
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0604 ENGINE CONTROL MODULE
INTERNAL/EXTERNAL RAM ERROR
Circuit Description
The engine control module (ECM) is the control center
of the fuel injection system. It constantly looks at the in-
formation from various sensors, and controls the sys-
tems that after vehicle performance. The ECM also
performs the diagnostic function of the system. It can
recognize operational problems, alert the driver through
the Malfunction Indicator Lamp (MIL), and store a Diag-
nostic Trouble Code (DTC) or DTCs which identify the
problem areas to aid the technician in making repairs.
An electrically erasable programmable read only
memory (EEPROM) is used to house the program infor-
mation and the calibrations required for engine, trans-
axle, transaxle diagnostics operation. The ECM uses a
value called a checksum for error detection of the soft-
ware. The checksum is a value that is equal to all the
numbers in the software added together. The ECM adds
all the values in the software and if that value does not
equal the checksum value, a checksum error is indi-
cated.Conditions for Setting the DTC
The ECM detects more than 3 incorrect checksum.
Action taken when The DTCs 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.
Coolant fan turns on.
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.
DTC P0604 – Engine Control Module RAM Error
StepActionValue(s)YesNo
1
Perform an On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 3–
3
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 4Go to Step 2
4
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–264 ENGINE CONTROLS
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0605 ENGINE CONTROL MODULE
NMVY WRITE ERROR
Circuit Description
The engine control module (ECM) is the control center of
the fuel injection system. It constantly looks at the infor-
mation from various sensors, and controls the systems
that after vehicle performance. The ECM also performs
the diagnostic function of the system. It can recognize op-
erational problems, alert the driver through the Malfunc-
tion Indicator Lamp (MIL), and store a Diagnostic Trouble
Code (DTC) or DTCs which identify the problem areas to
aid the technician in making repairs. An electrically eras-
able programmable read only memory (EEPROM) is
used to house the program information and the calibra-
tions required for engine, transaxle, transaxle diagnos-
tics operation. The ECM uses a value called a checksum
for error detection of the software. The checksum is a val-
ue that is equal to all the numbers in the software added
together. The ECM adds all the values in the software
and if that value does not equal the checksum value, a
checksum error is indicated.Conditions for Setting the DTC
The ECM detects more than 3 incorrect checksum.
Action taken when The DTCs 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.
Coolant fan turns on.
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.
DTC P0605 Engine Control Module NMVY Write Error
StepActionValue(s)YesNo
1
Perform an On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 3–
3
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 4Go to Step 2
4
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
ENGINE CONTROLS 1F–283
DAEWOO M-150 BL2
HARD START
Definition: The engine cranks OK, but does not start for
a long time. The engine eventually runs or may start and
immediately die.Important: Ensure that the driver is using the correct
starting procedure. Before diagnosing, check service
bulletins for updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Connect the scan tool to the Data Link Connector
(DLC).
2. Check the Engine Coolant Temperature (ECT)
sensor and the Intake Air Temperature (IAT)
sensor using the scan tool.
3. Compare the coolant temperature and the IAT
with the ambient temperature when the engine is
cold.
Do the ECT and the IAT readings differ from the
ambient temperature by more than the value
specified?
3C (5F)Go to Step 3Go to Step 4
3
1. Measure the resistance of the ECT sensor and
the IAT sensor.
2. Compare the resistance value to specifications
using the Temperature Vs. Resistance tables for
DTCs P0118 and P0113.
3. If the resistance is not the same, replace the
faulty sensor.
Is the repair complete?
–
System OK
–
4
1. Check for a sticking throttle shaft or a binding
linkage that may cause a high Throttle Position
(TP) sensor voltage. Repair or replace as
needed.
2. Check the TP sensor voltage reading with the
throttle closed.
Does the voltage measure within the value
specified?
0.4–0.8 VGo to Step 5Go to Step 26
5
1. Check the Manifold Absolute Pressure (MAP)
sensor response and accuracy.
2. Replace the MAP sensor as needed.
Is the repair complete?
–
System OKGo to Step 6
6
Check the fuel pump operation.
Does the fuel pump operate for the specified time
when the ignition switch is turned ON?
2 secGo to Step 7
Go to “Fuel
Pump Relay
Circuit Check”
7Check the fuel system pressure.
Is the fuel pressure within the specifications?380 kPa
(55 psi)
Go to Step 8Go to Step 27
8Check for water contamination in the fuel.
Is fuel contaminated?–Go to Step 9Go to Step 10
9Replace the contaminated fuel.
Is the repair complete?–System OK–
1F–290 ENGINE CONTROLS
DAEWOO M-150 BL2
DETONATION/SPARK KNOCK
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Fill the fuel tank with a known good grade of
gasoline that has the octane rating of the value
specified.
2. Reevaluate the vehicle’s performance.
Does the detonation problem still exist?
91 octaneGo to Step 3System OK
3
1. Inspect for low engine coolant level.
2. Check for restricted airflow to the radiator or
restricted coolant flow.
3. Check for a faulty thermostat.
4. Check for an incorrect coolant solution.
Is the problem found?
–
Go to Step 4Go to Step 5
4
Repair or replace any cooling system components
as needed.
Is the repair complete?
–
System OK
–
5
1. Check the engine coolant temperature using the
scan tool.
2. Replace the Engine Coolant Temperature (ECT)
sensor if the resistance is not within specifications
as listed in the Diagnostic Aids for diagnostic
trouble code P0118.
Is the problem found?
–
Go to Step 6Go to Step 7
6
Replace the ECT sensor or repair the circuit as
needed.
Is the repair complete?
–
System OK
–
7
1. Check the ignition system output with a spark
tester.
2. Inspect the spark plugs for the proper heat range
and gap.
3. Check for the proper operation of the ignition
controls.
Is the ignition system operating properly?
–
Go to Step 9Go to Step 8
8
Repair or replace the ignition system components as
needed.
Is the repair complete?
–
System Ok
–
9
1. Connect the scan tool to the Data Link Connector
(DLC).
2. Road test the vehicle at the speed of the
complaint.
3. Monitor the long term fuel trim reading from the
scanner data stream.
Is the long term fuel trim reading above the value
specified?
25%
Go to
“Diagnostic Aids
for DTC P0171”
Go to Step 10
10Check the fuel system pressure.
Is the problem found?380 kPa
(55 psi)
Go to Step 11Go to Step 12
11
Repair or replace the fuel system components as
needed.
Is the repair complete?
–
System OK
–
1F–296 ENGINE CONTROLS
DAEWOO M-150 BL2
POOR FUEL ECONOMY
Definition: Fuel economy, as measured by an actual
road test, is noticeably lower than expected. Also, fuel
economy is noticeably lower than it was on this vehicle
at one time, as previously shown by an actual road test.
Important: Driving habits affect fuel economy. Check
the owner’s driving habits by asking the following ques-
tions:1. Is the A/C system (i.e. defroster mode) turned on all
the time?
2. Are the tires at the correct air pressure?
3. Have excessively heavy loads been carried?
4. Does the driver accelerate too much and too often?
Suggest the driver read the section in the owner’s
manual about fuel economy.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Inspect the air filter for excessive contamination.
2. Inspect for fuel system leaks.
Are all needed checks complete?
–
Go to Step 3
–
3
1. Inspect the spark plugs for excessive wear,
insulation cracks, improper gap, or heavy
deposits.
2. Replace any faulty spark plugs.
3. Inspect the ignition wires for cracking, hardness,
and proper connections.
Are all needed checks and repairs complete?
–
Go to Step 4
–
4
1. Inspect the engine coolant level.
2. Check the thermostat for being always open or for
an incorrect heat range.
3. Replace the thermostat as needed.
Are all needed checks and repairs complete?
–
Go to Step 4
–
5
1. Check the transaxle shift pattern. Ensure all
transaxle gears are functioning.
2. Check for proper calibration of the speedometer.
3. Check the brakes for dragging.
4. Check the cylinder compression.
5. Repair, replace, or adjust any components as
needed.
Are all checks and needed repairs complete?
–
System OK
–
ENGINE CONTROLS 1F–297
DAEWOO M-150 BL2
ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING
Definition: The engine runs unevenly at idle. If the condi-
tion is bad enough, the vehicle may shake. Also, the idle
varies in rpm (called “hunting”). Either condition may be
severe enough to cause stalling. The engine idles at in-
correct idle speed.Important: Before diagnosing the symptom, check ser-
vice bulletins for updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Connect the scan tool to the Data Link Connector
(DLC).
2. Monitor the oxygen sensor (O2S) reading at
different throttle positions.
Does the O2S change quickly from rich to lean at
the different throttle positions?
–
Go to Step 5Go to Step 3
3
Check the O2S for contamination from fuel or
improper use of room temperature vulcanizing
sealant.
Is the O2S contaminated?
–
Go to Step 4Go to Step 5
4Replace the contaminated O2S as needed.
Is the repair complete?–System OK–
5
1. Check for a sticking throttle shaft or binding
throttle linkage that may cause incorrect Throttle
Position (TP) sensor voltage.
2. Check the TP sensor voltage reading with the
throttle closed.
Is the TP sensor voltage within the value specified?
0.4–0.8 VGo to Step 6
Go to
“Diagnostic
Aids for DTC
P0123”
6
1. Check the Engine Coolant Temperature (ECT)
sensor voltage reading using the scan tool.
2. Compare the ECT sensor reading with the
ambient temperature when the engine is cold.
Does the ECT sensor temperature reading differ
from the ambient temperature by more than the
value specified?
3C (5F)Go to Step 7Go to Step 9
7
Check for high resistance in the ECT sensor circuit
or the sensor itself.
Is the problem found?
–
Go to Step 8Go to Step 9
8
Replace the ECT sensor or repair the circuit as
needed.
Is the repair complete?
–
System OK
–
9
Check the Manifold Absolute Pressure (MAP)
sensor for response and accuracy.
Is the problem found?
–
Go to Step 10Go to Step 11
10
Replace the MAP sensor or repair the MAP sensor
circuit as needed.
Is the repair complete?
–
System OK
–
11
1. Road test the vehicle at the speed of the
complaint.
2. Monitor the long term fuel trim reading using the
scan tool.
Is the long term fuel trim reading within the value
specified?
–20–25%Go to Step 14Go to Step 12