Geely Emgrand X7. Manual part — 74

2.2.7.48 DTC P0685

1. DTC

description:

DTC P0685 Main Relay Malfunction

Main relay is used to provide power to fuel injectors and oxygen sensors and other components.
Battery provides power to main relay terminal No.86. ECM controls main relay ground through
ECM harness connector EM01 terminal No.62. ECM has a detection circuit. By monitoring the
feedback voltage, ECM determines whether the control circuit is open, short to ground or short to
power supply.

2. Conditions For Setting DTC and The Fault Location:

DTC
Code

DTC Detection
Strategy

Conditions For Setting The DTC
(Control Strategy)

Fault Locations

P0685

Main Relay
Malfunction

The main relay control circuit does
not match ECM expected status.

1. Main

Relay

2. Main Relay Circuit

3. ECM

3. Circuit

sketch

主继电器ER09

蓄电池

点火开关

EF22

EF40

EF35

EF14

EF16

IF33

MAIN PWR

EM01 B+

68

67

5

EM01 IG+

EM01

MPR

44

EM01

GND

3

EM01

GND

2

EM01

30

87

85

86

5

6

NL02-0060c

4. Diagnostic

Steps:

1 Appearance

Inspection

Inspect main relay for signs of damage.

Yes

Replace main relay ,go to steps10

No

Ignition switch

Main relay ER09

Battery

Engi

ne

co

ntr

ol mo

dul

e

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2

Inspect ECM harness connector EM01 terminal No.62.

A. Turn the ignition switch to OFF

position.

B. Dismantle of ECM harness

connector EM01.

C. Measure voltage between ECM

harness connector EM01 terminal
No.44 and a reliable ground.

Standard Voltage: 11-14V

D. Measure resistance between

ECM harness connector EM01
terminal No.44 and a reliable
ground.

Rated resistance：10KΩ or higher

ECM线束连接器

EM01

1

2

4

5

3

81

63

44

25

6

62

43

24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

7

26

42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27

45

46

61 60 59 58 57 56 55 54 53 52 51 50 49 48 47

64

65

66

80 79 78 77 76 75 74 73 72 71 70 69 68 67

NL02-0033c

Inspect whether according with the standard value?

3

Inspect ECM harness connector EM01 terminals No.5, 2 and 3

A. Turn the ignition switch to OFF position.

B. Dismantle of ECM harness connector EM01.

C. Measure resistance between ECM harness connector EM01 terminal No.5 and a reliable

ground.

Rated resistance：10KΩ or higher

D. Connect EM01 terminal NO.2 and 3 short to ground.

E. Measure voltage between EM01 terminal No.5 and a reliable ground.

Standard Voltage: 11-14V

Inspect whether according with the standard value?

4

Inspect the ignition switch input signal.

A Turn the ignition switch to the ON position.

B. Measure voltage between ECM harness connector EM01 terminal No.68 and a reliable

ground.

Standard Voltage: 11-14V

C. Turn the ignition switch to the OFF position.

No

Go to step 5

Yes

No

Repair the circuit from the battery to the
EM01 terminal #62. Go to step 10.

Yes

ECMharness connectorEM01

296

Whether voltage value is normal or not ?

5

Inspect the voltage of the main relay terminals No.87 and 86.

A. Dismantle the main relay.

B. Measure voltage between the main relay terminal No.87 and 86 with a reliable ground.

Standard Voltage: 11-14V

C. Measure resistance between the main relay terminal No.87 and 86 with a reliable ground.

Rated resistance：10KΩ or higher

Inspect whether according with the standard value?

6

Inspect main relay terminal No.30.

A. Install the main relay.

B. Connect ECM harness connector

EM01 terminal No.2 and 3 to
ground.

C. Measure voltage between main

relay terminal No.3 and a reliable
ground.

Standard Voltage: 11-14V

Check if it meet standard value ?

ER03

85

86

87

30

30

87

86

85

ER05

30

87

86

85

ER06

30

87

87a

86

85

ER11

ER08

ER0

9

85

86

87

30

ER10

2

1

5

3

2

1

5

3

2

1

5

3

ER04

ER02

2

1

5

3

2

1

5

3

ER01

ER07

2

1

5

3

1

2

3

4

11

12

13

14

15

16

5

6

7

8

9

10

EF0

8

EF0

7

EF2

7

EF2

6

EF2

2

EF2

9

EF0

3

EF0

6

EF0

9

EF2

5

EF1

7

EF1

6

EF1

5

EF3

5

EF2

1

EF

1

4

EF

0

1

EF

0

2

EF

0

4

EF

1

0

EF

1

1

EF

1

8

EF

2

4

NL02-0045c

7

Inspect continuity between main relay and ECM harness connector.

A. Dismantle the main relay.

B. Measure resistance between main relay terminal No.30 and ECM harness connector EM01

terminals No. 5.

Standard Resistance: Less than 1 Ω

Check if it meet standard value ?

No

Replace the main relay. Go to step 10.

Yes

No

Repair the circuits from the battery to the main
relay terminals #86 and #87. Go to step 10.

Yes

No

Repair the circuit from the battery to
the EM01 terminal #3. Go to step 10.

Yes

Go to step 8

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8

Inspect the ECM Power Supply Circuits.

Refer to 2.2.7.43 DTC P0562 P0563.

Inspect whether the ECM power supply circuit and ground circuit are normal.

9 Replace

ECM

See 2.2.8.1 Replacement of Engine Control Module.

10

Use fault diagnosis tester to confirm if DTC is stored again .

A. Connect fault diagnosis tester to the data link connector.

B. Rotated ignition switch to ON position

C. Clear DTC code.

D. Start and run the engine at idle speed to warm up the engine for at least 5 min.

E. Road test the vehicle for at least 10min.

F. Read control system DTC code again to confirm that the system has no DTC code output.

11 Troubleshooting

No

Refer to 2.2.7.3 Intermittent Fault
Inspection for intermittent fault.

Yes

Next

No

Repair ECM Power Supply Circuits.

Yes

No

Repair the circuits between main relay and
terminals #6 and #22 of the EM01. Go to step 10.

Yes

298