1F–98 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F140
DIAGNOSTIC TROUBLE CODE (DTC) – P0138 HEATED OXYGEN SENSOR HIGH
V O LTA G E
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 64 and
13. The Heated oxygen (O
2) sensor varies the voltage
within a range of about 1volt if the exhaust is rich, down
to about 100mm volts if the exhaust is lean. The Heated
O
2 sensor is like an open circuit and produces no volt-
age when it is below 360°C(600°F). An open O
2 sensor
circuit or a cold O
2 sensor causes “open loop” operation.
Conditions for Setting the DTC
The Heated oxygen sensor voltage is more than 4.8V
for at least 0.2 seconds.
A high voltage condition exists.
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
Normal scan tool voltage varies between 0.1volts and
0.9volts while in closed loop.
Inspect the oxygen (O
2) sensor wire. The O2 sensor
may be positioned incorrectly and contacting the ex-
haust manifold.
Check for an intermittent ground in the wire between
the O
2 sensor and the engine control module.
Perform an injector 2alance test to determine if a re-
stricted fuel injector may be causing the lean condi-
tion.
Vacuum of crankcase leaks will cause a lean running
condition.
An exhaust manifold gasket leak of a cracked ex-
haust manifold may cause outside air to be pulled into
the exhaust and past the sensor.
ENGINE CONTROLS 1F–99
DAEWOO M-150 BL2
DTC P0138 – Heated Oxygen 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. Turn the ignition switch to ON, with the engine
OFF.
2. Install a scan tool.
3. Engine at operating temperature.
4. Run the engine at 1,200rpm.
Does the scan tool the Heated oxygen(O2) sensor
voltage within the value specified?
More than
1.2V
Go to Step 3Go to Step 6
3
1. Turn the ignition switch to LOCK.
2. Disconnect the Heated O2 sensor connector and
engine control module (ECM) connector.
3. Check the Heated O2 sensor wire between the
Heated O2 sensor connector terminal 4 and ECM
connector terminal 35 for an open or short to
battery voltage.
Is the problem found?
–
Go to Step 4Go to Step 5
4
1. Repair the wire of the connector terminal as
needed.
2. Clear the DTCs from the ECM.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the repair complete?
–
System OK
–
5
1. Turn the ignition switch to LOCK.
2. Replace the Heated O2 sensor.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?
–
Go to Step 7
–
6
1. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?
–
Go to Step 7
–
7
Check if any additional DTCs are set.
Are any DTCs displaced that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–100 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F140
DIAGNOSTIC TROUBLE CODE (DTC) – P0140 HEATED OXYGEN SENSOR NO
ACTIVITY
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 64 and
13. The oxygen (O
2) sensor varies the voltage within a
range of about 1volt if the exhaust is rich, down to about
100mm volts if the exhaust is lean. The O
2 sensor is like
an open circuit and produces no voltage when it is below
360°C(600°F). An open O
2 sensor circuit or a cold O2
sensor causes “open loop” operation.
Conditions for Setting the DTC
The engine controls system is in closed loop.
Engine Coolant Temperature is higher than 70°C
(140°F).
The mass air flow(MAF) is between 25kg/h and
50kg/h.
The engine speed is between 2,400rpm and 300rpm.
The vehicle speed is between 64km/h(12.4mph) and
80km/h(24.9mph).
The manifold air pressure is higher than 70kPa.
The ignition is at 10 volts.
No transition from rich side to lean side or lean side to
rich side during 7.8 seconds even with a forcing of O
2
sensor controller.
DTCs P0107, P0108, P0112, P0113, P0117, P0118,
P0122, P0123, P0137, P0138, P0137, P0138,P0137, P0138, P1671, P0300, P0335, P0336,
P0341, P0400, P0404, P0405, P0644, P0645 are
NOT SET.
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.
Disconnecting the ECM battery feed for 10 seconds.
Diagnostic Aids
Normal scan tool voltage varies between 0.15 to
8.5mV while in Closed Loop. If DTC P0140 is inter-
mittent, refer to “Intermittent” in this Section.
ENGINE CONTROLS 1F–101
DAEWOO M-150 BL2
DTC P0140 – Heated Oxygen Sensor No Activity
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. Run the engine to above the specified operating
temperature.
2. Install a scan tool.
3. Operate the engine above the specified rpm for
2minuets.
Does the scan tool the indicate Closed Loop?
80°C(176°F)
1,200 rpm
Go to Step 3Go to Step 4
3
1. Turn the Turn the ignition switch to ON.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the freeze frame
conditions and Conditions for Setting the DTC as
noted?
Does the scan tool the indicate Closed Loop?
–
Go to Step 12Go to Step 4
4
Disconnect the Heated O2 sensor connector and
jumper the Heated O2 sensor low circuit, terminal 4
to ground.
Is the HO2 voltage below the specified value and
does the scan tool indicate the heated oxygen
sensor heater voltage within the specified value?
0.5VGo to Step 5Go to Step 6
5
Check the Heated O2 sensor connector for
malfunction terminals or poor connection and repair
as necessary.
Is repair necessary?
–
Go to Step 12Go to Step 9
6
1. Turn the ignition switch to On.
2. Remove the jumper wire.
3. Using a digital voltmeter(DVM), measure the
voltage between the Heated O2 sensor signal
circuit, terminal 3 to ground.
Does the Heated O2 sensor voltage measure above
the specified value?
0.6VGo to Step 10Go to Step 9
7Does the Heated O2 sensor voltage measure below
the specified value?
0.3VGo to Step 11Go to Step 8
8
Check the Heated O2 sensor ground circuit, terminal
4 for an open or poor connection and repair as
necessary.
Is repair necessary?
–
Go to Step 12Go to Step 8
11
Check the Heated O2 sensor signal circuit, terminal
3 for an open or poor connection and repair as
necessary.
Is repair necessary?
–
Go to Step 12Go to Step 8
10
1. If disconnected, reconnect Heated O2 sensor
connector.
2. Using the scan tool, clear the DTCs.
3. Start the engine and idle at normal operating
temperature.
4. Operate the vehicle within the conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicated that this diagnostic has
run and passed?
–
Go to Step 13Go to Step 2
1F–102 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0140 – Heated Oxygen Sensor No Activity (Cont’d)
StepActionValue(s)YesNo
11
1. Turn the ignition switch to LOCK.
2. Replace the Heated O2 sensor.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?
–
Go to Step 15
–
12
1. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?
–
Go to Step 15
–
13
Check if any additional DTCs are set.
Are any DTCs displaced that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–104 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F140
DIAGNOSTIC TROUBLE CODE (DTC) – P0141 HEATED OXYGEN SENSOR
HEATER MALFUNCTION
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 44 and
13. The oxygen (O
2) sensor varies the voltage within a
range of about 1volt if the exhaust is rich, down to about
100mm volts if the exhaust is lean. The O
2 sensor is like
an open circuit and produces no voltage when it is below
360°C(600°F). An open O
2 sensor circuit or a cold O2
sensor causes “open loop” operation.
Conditions for Setting the DTC
Heated oxygen sensor 5V reference voltage supply
circuit high voltage or ground.
Heated oxygen sensor 5V reference voltage supply
circuit open.
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
Normal scan tool voltage varies between 0.1volts and
0.9 volts while in closed loop.
Inspect the oxygen (O
2) sensor wire. The O2 sensor
may be positioned incorrectly and contacting the ex-
haust manifold.
Check for an intermittent ground in the wire between
the O
2 sensor and the engine control module.
Perform an injector 2alance test to determine if a re-
stricted fuel injector may be causing the lean condi-
tion.
Vacuum of crankcase leaks will cause a lean running
condition.
An exhaust manifold gasket leak of a cracked ex-
haust manifold may cause outside air to be pulled into
the exhaust and past the sensor.
ENGINE CONTROLS 1F–105
DAEWOO M-150 BL2
DTC P0141 – Heated Oxygen Sensor Heater Malfunction
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. Turn the ignition switch to LOCK.
2. Disconnect the Heated O2 sensor connector and
engine control module (ECM) connector.
3. Check the Heated O2 sensor heater wire
between the Heated O2 sensor connector
terminal 4 and ECM connector terminal 35 for an
open or short to ground.
Is the problem found?
–
Go to Step 3Go to Step 4
3
1. Repair the wire of the connector terminal as
needed.
2. Clear the DTCs from the ECM.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the repair complete?
–
System OK
–
4
1. Turn the ignition switch to LOCK.
2. Replace the Heated O2 sensor.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?
–
Go to Step 6
–
5
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.