Geely Emgrand X7. Manual part — 50
Geely Emgrand X7. Manual part - 50
2.2.7.24 DTC P0137 P0138 P0140
1. DTC
description:
DTC P0137
Rear Oxygen Sensor Circuit Short to Low Voltage
DTC P0138
Rear Oxygen Sensor Circuit Short to High Voltage
DTC P0140
Rear Oxygen Sensor Circuit Open
After the vehicle started, ECM works in open-loop mode, in which ECM ignores the heated type
oxygen sensor signal voltage when calculating the Air-Fuel ratio. The control module provides
approximately 450mV reference voltage to the heated oxygen sensor. When the engine starts
running, the heated type oxygen sensor will be heated and begin to generate a 0-0.1V voltage. This
voltage fluctuates. Once the control module detects that the heated oxygen sensor voltage exceeds
a threshold voltage, it will immediately enter into the closed-loop mode. Control module
determines the Air-fuel ratio using the received heated oxygen sensor voltage signal. If the heated
type oxygen sensor voltage increases to above the reference voltage (tend to 1 V), the mixture is
too thick. If the heated oxygen sensor voltage decreases to below the reference voltage (tend to
0mV), it indicates that the air fuel mixture is too thin.
•
ECM provides a signal through ECM harness connector EM01 terminal No.48 to rear oxygen
sensor wiring harness connector EM03 terminal B.
•
ECM provides an internal low reference voltage through ECM harness connector EM01
terminal No.73 to front oxygen sensor wiring harness connector EM03 terminal No.A.
2. Conditions For Setting DTC and The Fault Location:
DTC
Code
DTC Detection
Strategy
Conditions For Setting The DTC
(Control Strategy)
Fault
Locations
P0137
Short to Ground When
Cold
1. Engine Running Longer than 60s.
2. Water temperature is more than
70°C(158 ºF)。
3. Rear Oxygen Sensor Short to
Ground
4. Duration Longer Than 25s.
P0138
Post-catalytic Oxygen
Sensor Voltage Too
High
1. Engine Running Longer than 60s.
2. Water temperature is more than
70°C(158 ºF)。
3. Rear oxygen sensor signal is
terminated at the power supply.
4. Duration Longer Than 13s.
P0140
1. Oxygen Sensor
Signal Circuit
Open
2. Oxygen Sensor
With High
1. Engine Running Longer than 60s.
2. Water temperature is more than
70°C(158 ºF)。
3. Rear oxygen sensor signal
1. Sensor
Circuit
2. Sensor
3. ECM.
199
Resistance at High
Temperature
exceeds a reasonable range.
4. Duration Longer Than 165s.
3. Circuit
sketch
EF22
主继电器ER09
87
30
86
85
ED01
44
EM01
EM01
23
EM01
48
D
C
B
A
D
C
B
A
发
动
机
控
制
模
块
蓄电池
EF40
前氧传感器
EM01
EM01
O2AHTR
O2AHI
V5RTN3
O2BHTR
O2BHI
47
73
24
后氧传感器
MPR
NL02-0039c
4. Diagnostic
Steps:
Step 1
Connect a fault diagnosis tester.
Step 2
Start engine and turn on the fault diagnosis tester.
Step 4
Observe oxygen sensor output voltage, the data should be within 0.16-0.7V
unchanged.
Step 5
Carry out the oxygen sensor signal test.
(a) If the voltage data is consistently lower than 0.45 V (mixture too thin), carry out the
Step 3
(d) Select on the fault diagnosis tester: Engine / Read Data Flow / Group 1 Oxygen
Sensor Voltage 2 (Rear Oxygen Sensor).
Yes
Intermittent fault refers to 2.2.7.3 List of
Intermittent Fault.
No
Next
Next
Next
Main relay ER09
Front oxygen sensor
Rear oxygen sensor
Battery
Engi
ne
co
ntr
ol mo
dul
e
200
following inspection steps:
z Spray proper amount of propane gas into the intake.
z Check whether the rear oxygen sensor voltage data has a significant change, as it will cause
signal voltage to rise rapidly.
(b) If the voltage data is consistently higher than 0.45 V (mixture too thick), carry out the
following inspection steps:
z Put the transmission gear into neutral.
z ?Apply hand brake.
z Press the accelerator pedal so the engine speed suddenly increases to 4,000 rpm and then
quickly release the accelerator pedal.
z Repeat the previous steps more than 3 times.
z Check whether the rear oxygen sensor voltage data has a significant change, as it will cause
signal voltage to decrease rapidly.
During the above test, the oxygen sensor signal voltage should have a significant change.
Is voltage changed significantly?
Step 6
Inspect there are no other control system DTC codes output.
(a) Connect fault diagnosis tester to the vehicle diagnostic interface.
(b) Turn ignition switch to ON position.
(c) Press the fault diagnosis tester power button.
(d) Select the following menu items: Engine/Read DTC codes.
(e) Read DTC codes.
DTC Codes Shown
To Step
DTC codes other than P0137, P0138, P0140
No
P0137. P0138. P0140
Yes
Step 7
Inspect the sealing of exhaust system.
(a) Inspect whether the three-way catalytic converter looks good (signs of excessive heat and
gasket missing, etc.).
(b) Inspect whether the exhaust pipe is intact and whether gasket is intact.
No
Replace the damaged components. Go to
step 15.
No
Refer to 2.2.7.14 DTC Chapter Index.
Yes
Yes
Inspect the cause for engine air-fuel ratio too lean/too rich.
Refer to 2.2.7.4 Fault Symptom Table.
No
201
Step 8
Measure rear oxygen sensor signal circuit.
(a) Rotated ignition switch to OFF
position .
(b) Disconnect the rear oxygen
sensor wiring harness connector
EM03.
(c) Rotated ignition switch to ON
position .
(d) Measure voltage between rear
oxygen sensor wiring harness
connector EM03 terminal B and a
reliable ground.
Standard Voltage: 0.35-0.5V
(e) Connect the rear oxygen sensor
wiring harness connector EM03.
后氧传感器线束连接器
EM03
A
B
C
D
NL02-0041c
Is voltage the specified value?
Step 9
Measure the rear oxygen sensor ground circuit.
(a) Rotated ignition switch to OFF position.
(b) Disconnect the rear oxygen sensor wiring harness connector EM03.
(c) Rotated ignition switches to ON position.
(d) Measure resistance between rear oxygen sensor EM03 terminals A and a reliable ground.
Standard Resistance: Less than 1 Ω
(e) Connect the rear oxygen sensor wiring harness connector EM03.
Is resistance the specified value?
Step 10
Replace the rear oxygen sensor.
Step 11
Inspect the rear oxygen sensor signal circuit.
Next
Go to step 15
No
Go to step 12
Yes
No
Go to step 11
Yes
Rear oxygen sensor harness
connectorEM03
202
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