2004 DAEWOO LACETTI Automatic

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 103
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the ignition ON.
2. Measure the voltage of terminal 1.
3. Measure the voltage of terminal 2.
Is the voltage within the values shown?.11–14VGo to Step 12Go to Step 13
12Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
13Replace the TCM.
Is the action complete?–Go to Step 14–
141. After the repair, use a scan tool ”clear info”
function and road test the vehicle.
2. Review the ”DTC info”.
Has the last test failed or is the current DTC dis-
played?–Begin diagno-
sis againRepair verified
exit DTC chart

5A1 – 104IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE(DTC) P0721
OUTPUT SPEED SENSOR(OSS) CIRCUIT
RANGE/PERFORMANCE
Circuit Description
The vehicle A/T OSS is a magnetic inductive pickup that
relays information relative to vehicle speed to the TCM.
Vehicle speed information is used by the TCM to control
shift timing, line pressure, and TCC apply and release.
The output speed sensor mounts in the case at the speed
sensor rotor, which is pressed onto the spur gear. An air
gap of 0.1mm~1.3mm(0.004~0.05in) is maintained be-
tween the sensor and the teeth on the spur gear teeth. The
sensor consists of a permanent magnet surrounded by a
coil of wire. As the differential rotates, an AC signal in-
duces a higher frequency and voltage measurement at the
sensor. Sensor resistance should measure
at 20°C
(68°F). Sensor can measure from 20HZ~8,000HZ.
Conditions for Setting The DTC
S Transaxle speed is less than 8,160rpm.
S The increasing rate of output speed is more than
45,000rpm/sec.
S System voltage is greater than 8.5 volts.
S Engine is running.
S No engine speed error DTCs P0727, P0725.S No transmission range sensor error DTC P0705.
S TCM or ECM is defective.
S Immediately after the above condition occurs.
Action Taken When The DTC Sets
S The Malfunction Indicator Lamp(MIL) will illuminate.
S The TCM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Failure Records buffer.
S Adopt Emergency/ Substitute mode and constant
4th gear.
S Open lock up clutch.
Conditions for Clearing The MIL/DTC
S The MIL will turn OFF when the malfunction has
not occurred after three–ignition cycles.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S Using a scan tool can clear history DTCs.
Diagnostic Aids
S When DTC P0721 sets, the possible cause of fault
could be OSS(Output speed sensor).

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 105
DAEWOO V–121 BL4
DTC P0721 – Output Speed Sensor(OSS) Circuit
Range/Performance
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check completed?–Go to Step 2Go to ”On–
Board Diagnos-
tic System
Check”
21. Install the scan tool.
2. Turn the ignition ON and record then clear
DTC(s), then turn the ignition OFF.
3. Raise and support the drive wheels, then start
the engine.
4. Gear position is D and observe the output
speed on the scan tool.
Is the speed within the values shown?190~9,762rpmGo to ”Diag-
nostic Aids”Go to Step 3
31. Turn the ignition LOCK.
2. Disconnect the transaxle wiring connector.
3. Measure the resistance between terminals 1
and 2 of the transaxle wiring connector.
Is the resistance within the values shown?
Go to Step 9Go to Step 4
41. Remove the oil pan.
2. Disconnect the output speed sensor wiring
connector.
3. Measure the resistance between terminal 1 of
the output speed sensor wiring connector and
terminal 1 of the transaxle wiring connector.
4. Measure the resistance between terminal 2 of
the output speed sensor wiring connector and
terminal 2 of the transaxle wiring connector.
Is the resistance within the values shown?0ΩGo to Step 6Go to Step 5
5Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
61. Turn the ignition ON.
2. Measure the voltage of terminal 1.
3. Measure the voltage of terminal 2.
Is the voltage within the values shown?11–14VGo to Step 7Go to Step 8
7Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
8Replace the input speed sensor.
Is the action complete?–System OK–
91. Disconnect the transaxle wiring connector and
TCM connector.
2. Measure the resistance between terminal 1 of
the transaxle wiring connector and terminal
B10 of the TCM wiring connector.
3. Measure the resistance between terminal 2 of
the transaxle wiring connector and terminal B5
of the TCM wiring connector.
Is the resistance within the values shown?0ΩGo to Step 11Go to Step 10
10Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–

5A1 – 106IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the ignition ON.
2. Measure the voltage of terminal 1.
3. Measure the voltage of terminal 2.
Is the voltage within the values shown?.11–14VGo to Step 12Go to Step 13
12Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
13Replace the TCM.
Is the action complete?–Go to Step 14–
141. After the repair, use a scan tool ”clear info”
function and road test the vehicle.
2. Review the ”DTC info”.
Has the last test failed or is the current DTC dis-
played?–Begin diagno-
sis againRepair verified
exit DTC chart

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 107
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE(DTC) P0722
OUTPUT SPEED SENSOR(OSS) CIRCUIT NO SIGNAL
Circuit Description
The vehicle A/T OSS is a magnetic inductive pickup that
relays information relative to vehicle speed to the TCM.
Vehicle speed information is used by the TCM to control
shift timing, line pressure, and TCC apply and release.
The output speed sensor mounts in the case at the speed
sensor rotor, which is pressed onto the spur gear. An air
gap of 0.1mm~1.3mm(0.004~0.05in) is maintained be-
tween the sensor and the teeth on the spur gear teeth. The
sensor consists of a permanent magnet surrounded by a
coil of wire. As the differential rotates, an AC signal in-
duces a higher frequency and voltage measurement at the
sensor. Sensor resistance should measure
at 20°C
(68°F). Sensor can measure from 20HZ~8,000HZ.
Conditions for Setting The DTC
S If the gear shift is not in progress and the selector
lever position is ”1”, ”2”, ”3”, ”D”, or ”Z3” and the
transaxle output speed is less than the limit value of
transaxle output speed for plausibility check of
transaxle output speed and the turbine speed is
greater than the limit value of turbine speed for
plausibility check of transaxle output speed then the
error bit will be set.S System voltage is greater than 7 volts.
S Engine is running.
S No input speed error DTCs P0715, P0716, and
P0717.
S No transmission range sensor error DTC P0705.
S TCM or ECM is defective.
S Immediately after the above condition occurs.
Action Taken When The DTC Sets
S The Malfunction Indicator Lamp(MIL) will illuminate.
S The TCM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Failure Records buffer.
S Vehicle running remains actual gear.
S Open lock up clutch.
Conditions for Clearing The MIL/DTC
S The MIL will turn OFF when the malfunction has
not occurred after three–ignition cycles.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S Using a scan tool can clear history DTCs.
Diagnostic Aids
S When DTC P0722 sets, the possible cause of fault
could be OSS(Output speed sensor).

5A1 – 108IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
DTC P0722 – Output Speed Sensor(OSS) Circuit No Signal
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check completed?–Go to Step 2Go to ”On–
Board Diagnos-
tic System
Check”
21. Install the scan tool.
2. Turn the ignition ON and record then clear
DTC(s), then turn the ignition OFF.
3. Raise and support the drive wheels, then start
the engine.
4. Gear position is D and observe the output
speed on the scan tool.
Is the speed within the values shown?190~9,762rpmGo to ”Diag-
nostic Aids”Go to Step 3
31. Turn the ignition LOCK.
2. Disconnect the transaxle wiring connector.
3. Measure the resistance between terminals 1
and 2 of the transaxle wiring connector.
Is the resistance within the values shown?
Go to Step 9Go to Step 4
41. Remove the oil pan.
2. Disconnect the output speed sensor wiring
connector.
3. Measure the resistance between terminal 1 of
the output speed sensor wiring connector and
terminal 1 of the transaxle wiring connector.
4. Measure the resistance between terminal 2 of
the output speed sensor wiring connector and
terminal 2 of the transaxle wiring connector.
Is the resistance within the values shown?0ΩGo to Step 6Go to Step 5
5Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
61. Turn the ignition ON.
2. Measure the voltage of terminal 1.
3. Measure the voltage of terminal 2.
Is the voltage within the values shown?11–14VGo to Step 7Go to Step 8
7Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
8Replace the output speed sensor.
Is the action complete?–System OK–
91. Disconnect the transaxle wiring connector and
TCM connector.
2. Measure the resistance between terminal 1 of
the transaxle wiring connector and terminal
B10 of the TCM wiring connector.
3. Measure the resistance between terminal 2 of
the transaxle wiring connector and terminal B5
of the TCM wiring connector.
Is the resistance within the values shown?0ΩGo to Step 11Go to Step 10
10Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 109
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the ignition ON.
2. Measure the voltage of terminal 1.
3. Measure the voltage of terminal 2.
Is the voltage within the values shown?.11–14VGo to Step 12Go to Step 13
12Repair the malfunctioning terminals as necessary.
Is the action complete?–System OK–
13Replace the TCM.
Is the action complete?–Go to Step 14–
141. After the repair, use a scan tool ”clear info”
function and road test the vehicle.
2. Review the ”DTC info”.
Has the last test failed or is the current DTC dis-
played?–Begin diagno-
sis againRepair verified
exit DTC chart

5A1 – 110IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE(DTC) P0725
ENGINE SPEED INPUT CIRCUIT MALFUNCTION
Circuit Description
The transaxle control module(TCM) is an electronic de-
vice which monitors inputs to control various transaxle
functions including shift quality and transaxle sensors,
switches, and components to process for use within its’
control program. Based on this input information, the TCM
controls various transaxle output functions and devices.
DTC’s P0725, P0726 and P0727 are related to the same
circuit. These DTC’s will not illuminate the MIL, however,
the DTC will be stored in memory.
Information transmit between TCM and ECM through the
CAN line. information is as follows :
S Engine Malfunction Signal.
S Engine Speed.
S Engine Output Torque Reduction Signal.
S Engine Coolant Temperature.
Conditions for Setting The DTC
S The engine speed is greater than 7,000rpm.
S System voltage is too high or too low.
S CAN transmitting wiring harness shorted or open.S TCM or ECM is defective.
S Immediately after the above condition occurs.
Action Taken When The DTC Sets
S No lamp control required but diagnostic information
should be stored immediately when malfunction is
detected.
S Adopt Emergency/ Substitute mode and constant
4th gear.
S Open lock up clutch.
Conditions for Clearing the MIL/DTC
S The MIL will turn OFF when the malfunction has
not occurred after three–ignition cycles.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S Using a scan tool can clear history DTCs.
Diagnostic Aids
S Inspect the poor wiring harness connection for TCM
connectors and transaxle wiring connectors.
S Inspect the improperly formed or damaged termi-
nals.