3.5.7.25 P0976 P0977 

1. DTC 

description: 

DTC P0976 On/off electromagnetic valve S2 high current (short circuit) 

 

DTC P0977 On/off electromagnetic valve S2 low current (open circuit) 

The transmission control unit (TCU) uses a switching electromagnetic valve to select among different clutch 
elements within the transmission. During operation, the transmission control unit evaluates the current 
actually-delivered current to open/close the electromagnetic valve and compares with the expected. If the current 
is not in the pre-defined parameter currently, the DTC is set to display abnormal load of the transmission control 
unit. 

2.  Conditions For Setting DTC and The Fault Position : 

DTC Code 

DTC Detection Strategy 

Conditions For Setting The DTC 

(Control Strategy) 

Fault Position s 

P0976 

Feedback information of 
on/off electromagnetic valve 
S2 is that existence of short 
circuit. 

P0977 

Feedback information of 
on/off electromagnetic valve 
S2 is that existence of open 
circuit. 

1.  Ignition switch is in the “ON” 

position.  

2.      Electromagnetic valve power on

 

3.  TCU power supply voltage is 
normal 

1. Electromagnetic 

valve 

2. Electromagnetic 

valve circuit 

3. TCU 

3. Circuit 

sketch 

1367

 
 

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 
P0976 and P0977 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 P0976 P0977 

Yes 

DTCs other than DTCs P0976 and P0977 

No 

 

Gears switch 

Main relay 

JF-1 

 

Reverse output 

signal 

 

Start relay JB-2 

Shifter 

Electromagnetic 

valve 

1368

 
 

 

 

 

2 

Detect TCUpower supply circuit 

See 3.5.7.8 P0603 P0604 P1604 P1701 P1703 

 

 

3 

Detect ON/OFF electromagnetic valveS2resistance 

 

A.    Turn the ignition switch to the OFF position. 

B.  Disconnect the harness connector J-4 of the 

electromagnetic valve. 

C.    Measure the resistance between Terminals 22 and 

20 of the electromagnetic valve harness 
connector J-4. 

Standard resistant value :20.8Ω-23.2Ω 

 

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

Does it conform to the standard value? 

 

 

 

3 

Detect ON/OFF electromagnetic valve S2 circuit 

 

No

Yes

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

Next

No

Yes

Replace auto-transmission assembly, refer 
to3.4.7.6 auto-transmission assembly replacement 

Electromagnetic valveharness connectorJ-4

1369

 
 

 

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.22 

of the electromagnetic valve harness connector 
J-4 and Terminal 9 of the automatic control 
module J-1. 

D.    Measure the resistance between Terminal No.20 

of the electromagnetic valve harness connector 
J-4 and Terminal No.15 of the automatic control 
module J-1. 

E.    Turn the ignition switch to the ON position. 

F.  Measure voltage of electromagnetic valve 

harness connector J-4No.22 terminal and reliable 
grounding 

自动变速器控制模块线束连接器

J-1

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

SL03-0034c

G.  Measure the resistance between Terminal No.20 of the electromagnetic valve harness connector J-4 and 

secure ground wire. 

Results 

Test Items 

Standard Value 

J-4 (22) — J-1(9) 

Less than 3 Ω 

J-4 (20) — J-1(15) 

Less than 3 Ω 

J-4 (22) — Reliable grounding voltage value 

0 V 

J-4 (20) — Reliable grounding resistance value 

Less than 3 Ω 

Does it conform to the standard value? 

 

 

 

4 ReplaceTCU 

Refer to3.5.7.8 replace automatic transmission control module 

 

 

5 

Go to automatic transmission fresh process. 

Refer to3.5.7.4 Automatic transmission refresh process 

No

Yes 

Circuit malfunction, repair circuit. 

Next 

Auto-transmissioncontrol module harness connectorJ-1

1370