1F – 136IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
121. Repair the wire or the connector terminal as
needed.
2. Clear any DTCs from ECM.
3. Perform the Diagnostic System Check.
Is the repair complete?–System OK–
131. Replace the MTIA.
2. Clear any DTCs from ECM.
3. Perform the Diagnostic System Check.
Is the repair complete?–System OK–
141. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Perform the Diagnostic System Check.
Is the repair complete?–Go to Step 15–
15Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK
1F – 138IENGINE CONTROLS
DAEWOO V–121 BL4
Check for an intermittent ground in the wire between the
O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a restricted
fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running con-dition.
An exhaust manifold gasket leak of a cracked exhaust
manifold may cause outside air to be pulled into the ex-
haust and past the sensor.
DTC P0131 – Front Heated Oxygen Sensor Low Voltage
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Connect the scan tool to the data link connec-
tor (DLC).
2. Run the engine until it reaches operating tem-
perature.
3. Check for closed loop operation.
Does the engine control module(ECM) go into
closed loop?–Go to Step 3Go to Step 9
31. Run the until until it reaches operating temper-
ature?
2. Run the engine at 1,200rpm.
Does the scan tool read the upstream oxygen(O2 )
sensor signal voltage between the valve specified?0.25~0.65VGo to Step 5Go to Step 4
4Does the scan tool read the Oxygen sensor signal
voltage fixed below the valve specified?0.01VGo to Step 7Go to
”Diagnostic
Aids”
51. Disconnect the Oxygen sensor connector.
2. Run the warm engine at idle.
Does the scan tool read the Oxygen sensor signal
voltage between the valve specified?0.25~0.65VGo to
”Diagnostic
Aids”Go to Step 6
61. Turn the ignition switch to LOCK.
2. Check the Oxygen sensor wire between the
Oxygen sensor and the ECM connector termi-
nal 44 and 13 is open.
Is the problem found?–Go to Step 8Go to Step 11
71. Turn the ignition switch to LOCK.
2. Check the Oxygen sensor wire between the
Oxygen sensor and the ECM connector termi-
nal 44 for a short to ground.
Is the problem found?–Go to Step 8Go to Step 11
81. Repair the wire or the connector terminal as
needed.
2. Clear the any DTCs from the ECM.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the repair complete?–System OK–
91. Turn the ignition switch to LOCK.
2. Disconnect the Oxygen sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool the Oxygen sensor signal voltage
between the valve specified?0.3~0.6VGo to Step 10Go to Step 11
ENGINE CONTROLS 1F – 141
DAEWOO V–121 BL4
DTC P0132 – Front Heated Oxygen Sensor High Voltage
StepActionValue(s)YesNo
1Perform an Euro 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 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 upstream oxygen(O2) sen-
sor1 voltage within the value specified?More than
1.2VGo to Step 3Go to Step 6
31. Turn the ignition switch to LOCK.
2. Disconnect the O2 sensor connector and en-
gine control module (ECM) connector.
3. Check the O2 sensor wire between the O2
sensor and ECM connector terminal 44 for
short to battery voltage.
Is the problem found?–Go to Step 4Go to Step 5
41. 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–
51. Turn the ignition switch to LOCK.
2. Replace the O2 sensor.
3. Road tests the vehicle.
4. Perform the diagnostic system check.
Is the replacement complete?–Go to Step 7–
61. 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–
7Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK
ENGINE CONTROLS 1F – 143
DAEWOO V–121 BL4
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 10 sec-
onds.
Diagnostic Aids
Normal scan tool voltage varies between 0.15 to 8.5mV
while in Closed Loop. If DTC P0133 is intermittent, refer
to ”Intermittents” in this section.
DTC P0133 – Front Heated Oxygen Sensor No Activity
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Connect the scan tool to the data link connec-
tor (DLC).
2. Run the engine until it reaches operating tem-
perature.
3. Check for the closed loop operation.
Does the scan tool indicate the closed loop?–Go to Step 3Go to Step 4
31. Turn the ignition switch to LOCK.
2. Review the freeze frame data and note the pa-
rameters.
3. Operate the vehicle within the freeze frame
conditions and Conditions for Setting the DTC.
Does the scan tool indicate the closed loop?–Go to Step 12Go to Step 4
41. Disconnect the upstream oxygen(O2) sensor
connector.
2. Jumper the oxygen sensor connector terminal
1 to ground.
3. Turn the ignition switch to ON.
Does the scan tool read the oxygen sensor signal
voltage the specified valve?0.4~0.5VGo to Step 5Go to Step 8
5Check the oxygen sensorconnector for malfunction
terminals or poor connection and repair as neces-
sary.
Is repair necessary?–Go to Step 12Go to Step 6
61. Run the engine at idle.
2. Remove the jumper wire.
3. Measure the voltage between the oxygen sen-
sor connector terminal 3 and ground.
Does the oxygen sensor voltage measure above the
specified value?0.6VGo to Step 7Go to Step 11
71. Turn the ignition switch to LOCK.
2. Measure the voltage between the upstream O2
sensor connector terminal 3 and ground.
Does the oxygen sensor voltage measure above the
specified value?0.3VGo to Step 9Go to Step 11
8Repair the wire or the connector between the upstre
O2 sensor terminal 1 and the engine control module
(ECM) terminal 44 is open or a short to ground.
Is the repair complete?–Go to Step 11Go to Step 9
1F – 144IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
9Repair the wire and the connector terminal between
the oxygen sensor connector terminal 3 and the
ECM connector terminal 13 is open or a short to
ground.
Is the repair complete?–Go to Step 12Go to Step 10
101. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Perform the diagnostic system check.
Is the repair complete?–System OK–
11Replace the O2 sensor.
Is the repair complete?–Go to Step 12–
121. Clear any DTCs from the ECM.
2. Perform the diagnostic system check.
Is the repair complete.–Go to Step 13–
13Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK
ENGINE CONTROLS 1F – 145
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0135
FRONT HEATED OXYGEN SENSOR HEATER CIRCUIT
NOT FUNCTIONING
Circuit Description
Heated oxygen sensors (HO2S) are used for fuel control
and post catalyst monitoring. Each HO2S compares the
oxygen content of the surrounding air with the oxygen con-
tent in the exhaust stream. The HO2S must reach operat-
ing temperature to provide an accurate voltage signal. A
heating element inside the HO2S minmizes the time re-
quired for the sensor to reach operating temperature. Volt-
age is provided to the heater by the ignition 1 voltage cir-
cuit through a fuse. With the engine running, ground is
provided to the heater by the HO2S heater low control cir-
cuit, through a low side driver within the engine control
module (ECM). The ECM monitors the current flow
through the heater for diagnosis.
If the ECM detects that the HO2S heater current is above
or blelow a specified range, DTC P0135 seats.
Conditions for Setting the DTC
S DTCs P0106, P0117, P0118, P1017 are not set.
S Engine run time is greater than 30 seconds.
S Filtered O2 heater current is less than 0.1 amps.
Action Taken When the DTC SetsS The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip 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 Diagnostic Trouble Code (DTC) is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after three 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.
Diagnostic Aids
An intermittent may be caused by rubbed through wire in-
sulation or a wire contacting the exhaust.
Check for poor connection or damaged harness – inspect
harness connectors for the following conditions:
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
1F – 146IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged harness
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.
2. This step determines if DTC P0135 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S1 voltage dis-played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal 4 of the HO2S1 connector verifies
if voltage is available to the HO2S1 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S1
due to an open in the HO2S1 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0135 – Front Heated Oxygen Sensor Heater Circuit Not
Functioning
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”
2Notice : If the engine has just been operating, allow
the engine to cool for about one–half hour before
proceeding.
1. Turn the ignition switch ON, with the engine
OFF.
2. Install a scan tool.
Does the Front Heated Oxygen Sensor (HO2S1)
voltage gradually change toward the specified volt-
age?0 v or 1 vGo to Step 13Go to Step 3
31. Disconnect the HO2S1 electrical connector.
2. With a test light connected to ground, probe
the ignition feed circuit, terminal 2 of the con-
nector.
Does the test light illuminate?–Go to Step 4Go to Step 5
4Connect a test light between the ignition feed and
ground circuits, terminal 2 and 3 of the connector.
Does the test light illuminate?–Go to Step 6Go to Step 7
5Inspect the fuse in the engine fuse block.
Is the fuse open?–Go to Step 8Go to Step 9
6Check the connections terminal 2 and 1 at the
HO2S2 connector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 10
7Check the connections terminal 4 at the HO2S1 con-
nector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 11
81. Check for a short to ground in the HO2S1 igni-
tion feed circuit and repair as necessary?
2. Replace open fuse.
Is the action complete?–Go to Step 13–
ENGINE CONTROLS 1F – 149
DAEWOO V–121 BL4
S Check for an intermittent ground in the wire be-
tween the O2 sensor and the engine control mod-
ule.
S Perform an injector 2alance test to determine if a
restricted fuel injector may be causing the lean con-
dition.S Vacuum of crankcase leaks will cause a lean run-
ning condition.
S 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.
DTC P0137 – Rear Heated Oxygen Sensor Low Voltage
StepActionValue(s)YesNo
1Perform an Euro 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 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 downstream oxygen (O2)
sensor1 voltage within the value specified?0.07–0.52VGo to Step 4Go to Step 3
3Does the scan tool the heated oxygen (O2) sensor1
voltage within the value specified?0.1VGo to Step 9Go to
”Diagnostic
Aids”
41. 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 3 and
ECM connector terminal 36 for short to ground.
Is the problem found?–Go to Step 5Go to Step 6
51. 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–
61. Turn the ignition switch to LOCK.
2. Disconnect the Heated O2 sensor connector
and engine control module (ECM) connector.
3. Check the O2 sensor wire between the O2
sensor connector terminal 2 and ECM connec-
tor terminal 64 for short to ground.
Is the problem found?–Go to Step 7Go to Step 8
71. 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–
81. 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 10–