Chery Tiggo 5 (T21). Manual - part 78

06–

154

06

Check for Short

a. Use X-431 3G diagnostic tester to read the ECM DTC.
b. Refer to "DTC Confirmation Procedure".
c. Check if DTC P0645-00, P0646-00 or P0647-00 still exists.

Multimeter 

Connection

Condition

Specified 

Condition

E-033 (42) (MT) 

or E-033 (58) 

(CVT) or E-069 

(F1) - Body 

ground

Always

No continuity

E-033 (42) (MT) 

or E-033 (58) 

(CVT) or E-069 

(F1) - Battery 

positive

Always

No continuity

Repair or replace wire harness or 
connector (ECM - engine compartment 
fuse and relay box)

NG

4

Check for DTCs

OK

Replace ECM

NG

System is operating normally. 
Reassemble vehicle and perform a road test to confirm that malfunction reported by customer has 
been repaired.

OK

06–

155

06

DTC

P0688-00 EMC/PCM Power Relay Sense Circuit Open

ET21065015

BATTERY

ECM
MAIN 
RELAY

10A

EF19

10A

EF17

10A

EF40

A2

F14

2-20

RL

A4

2-35

L

2-5

Br

A6

2-15

2-16

RR

R

86

87

85

30

ENGINE 
COMPARTMENT 
FUSE AND 
RELAY BOX

IGNITION SWITCH
    ON OR START

A1

A2

A3

A4

A5

A6

A7

A8 A9 A10

F12

F24

F11

F23

F10

F22

F9

F21

F8

F20

F7

F19

F6

F18

F5

F17

F4

F16

F3

F15

F2

F14

F1

F13

Gr

E-076

W

E-069

E-076

E-069

B

E-033

49 50 51

63

64

15

16

31

32

47

48

33 34 35

17 18 19

1

2

3

52 53 54 55 56 57 58 59 60 61 62

36 37 38 39 40 41 42 43 44 45 46

20 21 22 23 24 25 26 27 28 29 30

4

5

6

7

8

9 10 11 12 13 14

1-47

Br

Br

1-48

E-028

2-63

B

B

2-64

E-026

ECM-2

E-033

ECM-1

E-035

37 38 39 40 41 42 43 44 45 46

47

48

25 26 27 28 29 30 31 32 33 34

35

36

13 14 15 16 17 18 19 20 21 22

23

24

1

2

3

4

5

6

7

8

9 10

11

12

B

E-035

06–

156

06

DTC Confirmation Procedure

Confirm that battery voltage is over 12 V before performing the following procedures.
 Turn ignition switch to LOCK.
 Connect X-431 3G diagnostic tester (the latest software) to Data Link Connector (DLC).
 Turn ignition switch to ON.
 Use X-431 3G diagnostic tester to record and clear the DTCs stored in the ECM.
 Select Read Code.
 If the DTC is detected, the malfunction indicated by the DTC is current. Go to the diagnosis procedure - Step 1.
 If DTC is not detected, the malfunction indicated by the DTC is intermittent (

See page 06-18

).

Diagnosis Procedure

a. Turn ignition switch to LOCK.
b. Check ECM grounds E-026 and E-028 (

See page 06-18

).

DTC Code

DTC Definition

DTC Detection 

Condition

Possible Cause

P0688-00

EMC/PCM Power 
Relay Sense Circuit 
Open 

Ignition switch ON

 Main Relay
 Wire harness or connector
 ECM

CAUTION

 When performing circuit diagnosis and test, always refer to the circuit diagram for specific circuit and 

component information.

1

Check ECM ground point

Repair or replace ground wire harness or 
ground point

NG

OK

06–

157

06

a. Unplug main relay and fuse EF40 from engine 

compartment fuse and relay box. 

b. Check if fuse EF40 is normal.
c. Check for continuity between terminals of main relay. 

a. Measure voltage between terminals of main relay (engine 

compartment fuse and relay box side) and body ground.

2

Check main relay and fuse

-

+

85

86

30

87

RT21060020

87

30

85

86

Multimeter 

Connection

Specified Condition

30 - 87

No continuity

30 - 87

Continuity

(when battery voltage is applied 

between terminals 85 and 86)

Replace main relay

NG

3

Check main relay circuit voltage

OK

RT21060030

-

+

V

30

85

86

87

Multimeter 

Connection

Condition

Specified 

Condition

Main relay 

terminals 87 and 

85 (engine 

compartment fuse 

and relay box 

side) - Body 

ground

Always

11 to 14 V

Repair or replace wire harness or 
connector (main relay - battery)

NG

OK