Geely Emgrand X7. Manual part — 655

11.16.7 Diagnostic information and steps (without CAN)

11.16.7.1 Diagnosis descriptions

Refer to 11.16.2 Description and Operation, get familiar with the system functions and operation
before starting system diagnosis, so that it will help to determine the correct diagnostic steps, more
importantly, it will also help to determine whether the situation described by the customer is
normal.

11.16.7.2 Visual inspection

Inspect the after-sales optional device which may affect the normal operation of data
communication system.

–

Inspect components easy to access system to identify whether there is a significant damage
that may lead to the fault.

–

If the data communication system has a fault, inspect whether all data communication system
control module harness connectors have been correctly connected before repairing.

11.16.7.3 Fault symptom table

Symptoms Probability

and

Cause Measures

The diagnostic unit is
connected with the DLC.
The backlight of the
diagnostic unit does not turn
on and is unable to enter the
main interface.

– Diagnostic

unit

– Wire

harness

and

connector

– Fuse

– Replace

diagnostic

apparatus

– Repair

circuit.

– Replace

fuse

The diagnostic unit is unable
to be communicated with all
controllers.

– Diagnostic

unit

– Wire

harness

and

connector

– Replace

diagnostic

apparatus

– Repair

circuit.

The diagnostic unit is unable
to be communicated with the
ECM.

– Wire

harness

and

connector

–

Engine anti-theft system
control module

– ECM

– Repair

circuit.

–

Replace engine anti-theft
system control module

– Replace

ECM

The diagnostic unit is unable
to be communicated with the
ABS hydraulic electronic
control unit.

– Wire

harness

and

connector

–

ABS hydraulic electric
control unit

– Repair

circuit.

– Replace

ABS

hydraulic

electronic control unit

The diagnostic unit is unable
to be communicated with the
SRS control module.

– Wire

harness

and

connector

–

SRS airbag control
module

– Repair

circuit.

– Replace

SRS

(Supplementary Restraint
System) control module

The diagnostic unit is unable
to be communicated with the
BCM.

– Wire

harness

and

connector

– BCM

– Repair

circuit.

– Replace

BCM

The diagnostic unit is unable
to be communicated with the
engine anti-theft system
control module.

– Wire

harness

and

connector

–

Engine anti-theft system
control module

– Repair

circuit.

–

Replace engine anti-theft
system control module

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11.16.8 Diagnostic information and step (with CAN)

11.16.8.1 Diagnosis descriptions

Refer to 6.4.2.1 System Working Principle to get familiar with the system functions and
operations before starting the system diagnosis, so that it will facilitate the correct diagnostic steps,
more importantly, it will also help to determine whether the situation described by the customer
described is normal.

11.16.8.2 Visual inspection

Inspect the after-sales optional device which may affect the normal operation of data
communication system.

–

Inspect components easy to access system to identify whether there is a significant damage
that may lead to the fault.

–

If the data communication system has a fault, inspect whether all data communication system
control module harness connectors have been correctly connected before repairing.

11.16.8.3 CAN bus fault prevention

–

Do not stretch CAN bus wiring harness.

–

Do not disassemble the CAN bus wiring harness by more than 4 cm (1.6 in).

–

Do not connect CAN bus wiring harness with other conducting wires.

–

Use the fault diagnosis tester recommended by the manufacturer to do the diagnosis.

11.16.8.4 CAN bus Integrity diagnosis

To check whether CAN bus is normal, perform the CAN bus integrity diagnosis to confirm
whether the fault is caused because the physical circuit CAN bus is open. For specific operations.
Please refer to 5.4.7.1 CAN Bus Network Integrity Checking.

11.16.8.5 CAN bus wiring harness repair specification

–

CAN_H and CAN_L two lines must use articulated way.

–

When CAN bus circuit fault occurs, the length of wire joints should not exceed L1: 50 mm
(1.97 in).

–

If the circuit is open at two or more places. The distance between the two places must be
more than L2: 100 mm (3.94 in), then it is allowed to repair. Otherwise replace the CAN bus
wiring harness.

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线束维修间距：>100 mm

线束维修最大尺寸： 50mm

FE11-1505b

11.16.8.6 CAN bus signal diagnostic

The oscilloscope dual-channel input can be used to monitor the signal on the CAN bus. The signal
should have the following features:

1. CAN_H bus voltage signal is 2.5-3.5 V, CAN_L bus voltage signal is 1.5-2.5 V.

2. Two signals mirror each other.

3. The signal transmission starts while the ignition switch is turned on, but stops 2 s after the

ignition is switched off.

Max.dimension of harness

service: 50mm

Space of harness service: ＞100mm

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11.16.9 Removal and installation

11.16.9.1 Fault diagnosis tester can not start up normally

The diagnostic step refers to 2.2.7.2 Inspection of Control System.

11.16.9.2 CAN bus network integrity inspection

1. Turn off ignition switch, and use ohmmeter to measure fault diagnosis interface PIN6 and

PIN14.

2. If the ohmmeter shows about

110-125 Ω resistance or
non-conduction, the CAN bus is
incomplete.

3. Inspect the ECM and the BCM

harness connectors in order to
confirm the CAN bus connection
is normal. If there are undesirable
situations such as open circuit or
bad connection, carry out repairs.

Note: CAN bus repairs must follow
the repair specification. Refer to
6.4.6.5 CAN Bus Wiring Harness
Repair Specification.

FE11-1419b

4. If the ohmmeter shows that the

resistance is about 55-63 Ω, it
means the CAN bus from the
BCM to ECM is complete.

FE11-1420b

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