3.5.7.14  P0721 P0722 

1. DTC 

description: 

DTC P0721 Output shaft speed sensor value 

 

DTC P0722 Output shaft speed sensor signal is instability 

The ISS sensor is a Hall Effect sensor. The ISS sensor is integrated with the OSS sensor and installed on the main 
housing of the automatic transmission (below the valve body). 

2.  Conditions for setting DTC and the gault position : 

DTC code 

DTC detection strategy 

Conditions for setting the DTC (control 

strategy) 

Fault position s 

P0721 

Compared the output 
shaft speed (OSS) sensor 
with the external 
equivalent revolution 
speed signal, verify the 
integrity thereof. 

P0722 

The output speed sensor 
receives the intermittent 
pulse or interference 
pulse. 

Ignition switch is in ON position 

1. Electromagnetic 

valve and harness 
assembly 

2. TCU 

3.

 Automatictrans
mission assembly 

3. Circuit 

sketch 

1311

 
 

T

C

U

电磁阀

换挡器

档位开关

LEVER

REVERSE

START

VBS5

VBS6

VBS7

V

BS8

VBS9

VBS1

0

O

n

O

ff

1

O

n

O

ff

2

O

n

O

ff

3

O

n

O

ff

4

EMM

INPUT

SHAFT

SPEE

D

SENSOR

OU

TPUT

SHAFT

t

SPE

ED

SENSOR

25

26

10

11

9

8

13

12

24

23

22

21

20

7

6

5

4

3

2

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

J-4

1

18

8

1

3

2

12

14

4

11

12

9

10

15

2

1

4

3

6

5

7

7

J-5

5

16

17

J-5

4

J-5

1

J-5

6

J-5

2

J-5

3

4

11

10

10

15

3

CAN H

启动继电器

倒车信号

输出

主继电器

JF-1

IG2

JB-2

CAN L

10

20

J-3

J-1

J-3

J-2

J-2

J-3

J-3

J-3

J-1

8

J-3

J-3

J-3

J-3

J-3

J-3

J-3

J-3

J-1

J-1

J-1

J-1

J-1

J-1

J-1

J-1

J-1

J-1

J-1

J-1

IF36

NL03-2005c

 

4. Diagnostic 

procedures: 

Note: Before carrying out this diagnosis step, observe the data list on fault diagnosis tester and analyze the 
accuracy of the data, as these will help with quick diagnosis. 

1 

Read the fault code again after clearing away the fault code to check if fault codes, except DTC 
P1605, P1610 and P1611 exist in the control system. 

A.    Connect fault diagnosis tester to the datalink connector. 

B.  Rotated ignition switch to ON position 

C.    Switch on fault diagnostic device power supply 

D.  Clear DTC code. 

E.    Reset reading fault code, and check if DTCs meet setting condition of fault code in current 

DTC Codes Shown 

To Step 

DTC P0721 P0722 

Yes 

DTC except for DTC P0721 P0722 

No 

 

Gears switch 

Main relay 

JF-1 

 

Reverse output 

signal 

 

Start relay JB-2 

Shifter 

Electromagnetic 

valve 

1312

 
 

 

 

 

2 

Detect Output shaft speed sensor reference voltage 

 

A.    Turn the ignition switch to the OFF position. 

B.  Disconnect the harness connector J-4 of the 

electromagnetic valve. 

C.    Turn the ignition switch to the ON position. 

D.    Measure the voltage between Terminals 8 and 9 

of the electromagnetic valve harness connector 
J-4. 

Standard voltage values: is more than10V 

Does it conform to the standard value? 

电磁阀线束连接器 J-4

1

8

20

14

9

15

10

16

11

17

12

18

13

19

2

21

3

22

4

23

5

24

6

25

7

26

SL03-0036c

 

 

 

 

3 

Detect output shaft speed sensor signal voltage 

A.    Turn the ignition switch to the OFF position. 

B.    Disconnect the harness connector J-4 of the electromagnetic valve. 

C.    Turn the ignition switch to the ON position. 

D.    Measure the voltage between terminals 8 and 10 of the electromagnetic valve harness connector J-4. 

Standard voltage: 4.9-5.1 V 

Does it conform to the standard value? 

 

 

 

 

4 

Detect output shaft speed sensor circuit 

No

Yes

Refer to3.4.7.6 fault diagnosis code (DTC) chapter 
index 

No

Yes

Refer to 3.4.7.8 Replacement of automatic 
transmission control module to replace TCU. 

No

Yes

Refer to 3.4.7.8 replacement of automatic 
transmission control module to replace TCU. 
 

Electromagnetic valve harness connectorJ-4

1313

 
 

 

A.  rotated ignition switch to OFF position. 

B.  Disconnect the harness connector J-4 of the 

electromagnetic valve. 

C.    Measure the resistance between Terminal No.8of 

the electromagnetic valve harness connector J-4 
and Terminal No.12 of the automatic control 
module J-3. 

D.    Measure the resistance between Terminal 9 of the 

electromagnetic valve harness connector J-4 and 
terminal No.2 of the automatic control module 
J-3. 

E.  Measure resistance of electromagnetic valve 

harness connector J-4 No ,10 terminal and 
automatic transmission control moduleJ-3No.1 
terminal 

自动变速器控制模块线束连接器 J-3

1

11

2

12

3

13

4

14

5

15

6

16

7

17

8

18

9

19

10

20

SL03-0036c

F.  Turn the ignition switch to ON position. 

G.    Measure the voltage between Terminal No.8of the electromagnetic valve harness connector J-4 and secure 

ground wire. 

H  Measure voltage of electromagnetic valve harness connector J-4 Terminal No.9 and reliable grounding 

Measure Voltage of electromagnetic valve harness connector J-4 No.10 terminal and reliable grounding 

Results 

Test Items 

Standard Value 

J-4(8) — J-3(12) 

Less than 3 Ω 

J-4(9) — J-3(2) 

Less than 3 Ω 

J-4(10)— J-3(1) 

Less than 3 Ω 

J-4(8) — Reliable grounding voltage value 

O V 

J-4(9) — Reliable grounding voltage value 

0 V 

J-4(10) — Reliable grounding voltage value 

O V 

Does it conform to the standard value? 

 

 

 

5 

Detect the output waveform of the output shaft speed sensor. 

 

No

Yes

Circuit malfunction, repair circuit. 

Auto-transmissioncontrol module harness connectorJ-3

1314