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Anti-theft Module IP25

Datalink Connector IP12

FE02-5002b

(a)

Disconnect engine immobilizer control module IP25 wiring
harness connector.

(b)

Test the terminal continuity using an ohmmeter.

Connecting Multimeter

Standard Value

IP12(7) - IP25(7)

Less than 1 Ω

(c)

Reconnect the engine immobilizer control module IP25 wiring
harness connector.

Normal?

No

Repair or replace the wiring harness
connector.

Yes

Step 16

Test to confirm.

Next

Step 17

End.

2.2.7.3 Intermittent Fault Check

Note

1. Clear DTC.

2. Carry out simulation tests.

3. Inspect and shake the wiring harnesses, connectors and terminals.

When DTC checks can not identify the fault, the fault occurs only occasionally in use. At this point you should test and confirm all
circuits and components that can possibly lead to the fault. In many cases, carrying out the basic checks flow chart shown in the
following can quickly and efficiently identify the Repair the faulty part. especially for harness connector poor contact.

Fault Definition: The fault currently does not appear, but the historical record indicates that the fault has appeared before. Or a
customer reported the fault and had it repaired, but because the fault is not relevant to the DTC code, the fault symptoms do not
appear.

Diagnostic Steps:

Step 1

Is the battery voltage normal?

(a)

Turn the ignition switch to "OFF" position.

(b)

Measure the battery voltage with a multimeter.

Engine

Control System JL4G18-D

2-35

According to the Measure value, choose the appropriate diagnostic
step.

Results

To Step

11 V or higher

Yes

Less than 11 V

No

No

Check the battery. Refer to 

2.11.2.1

 

Battery

Description and Operation

Yes

Step 2

Check visually and physically.

This step is an important method to initially identify the fault
location:

(a)

Check wiring harness for damage, wear and tear.

(b)

Check whether the wiring harness routed properly. Do not
place wiring harness near a device with high voltage or high
current running through:

•

Such as start motor, generator and other motor
components. When these components are working, they
will introduce great electromagnetic interference, thus
affecting the proper signal transmission, resulting in
system not working properly.

•

Ignition coil, ignition wires and other components.

(c)

Check whether there is a vacuum hose cracking, damage or
distortion. Confirm the hoses correct connection and routing.

(d)

Check whether there is air intake system leak, for example,
throttle body installation surface, idle speed control valve,
intake manifold sealing surface and so on.

(e)

Check the engine control module (ECM) ground and the body
ground whether there is oxidation, loose, incorrect position.
The control system ground can not be changed at will, as this
will affect the proper operation of the control system .

(f)

Check whether the battery positive and negative cable
connections are reliable, whether there is loose, oxidation,
corrosion and so on.

Next

Step 3

Check wiring harnesses and connectors.

(a)

Many intermittent faults are caused by vibration, distortion,
uneven roads, improper operation of components or
connectors dislocation.

(b)

If the circuit resistance is too high, it may result in components
not working properly. Use a scan tool to drive the actuators,
if not working, check whether the resistance in the circuit is
too high or other faults.

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Control System JL4G18-D

Engine

Next

Step 4

Reproduce the fault and use instruments to record engine control module data.

(a)

Connect a scan tool and use the data record function to
record road test data. After pressing the vehicle data recorder
button, the scan tool can record engine control module data
in the event of intermittent fault occurring, and then the data
can be used to identify the fault location.

(b)

Another diagnostic method is when the vehicle is driven
connect a digital multimeter to the suspicious circuit. Digital
multimeter abnormal readings may indicate the fault location.

Next

Step 5

Intermittent malfunction indicator light, but a DTC code is not set in the system.

Following conditions may cause intermittent malfunction indicator
light, but the system does not set the DTC codes:

(a)

Relay working abnormally, the engine control module
controlled electromagnetic valves or switches causing
electromagnetic interference.

(b)

Non-original or aftermarket accessories, such as a phone,
alarm, lights or radio equipment, not installed properly.

(c)

Intermittent malfunction indicator light control circuit short to
ground.

(d)

Engine control module ground loose.

Next

Step 6

Other checks.

(a)

Test whether Air-Conditioning compressor clutch diodes at
both ends and other diodes are in open circuit.

(b)

Check charging system whether there are following
conditions existing:

•

Generator rectifier fault within the electrical system may
result in the communication signal interference.

•

Generator output voltage is correct or not. If the generator
output voltage is lower than 9V or higher than 18V, repair
the charging system.

Next

Step 7

Refer to fault symptom table.

2.2.7.4 Fault Symptom Table

If a fault occurred, but no DTC code stored within ECM, or the fault cause can not be identified in the basic checks, you should
diagnose or exclude the fault based on the sequence listed in the following table.

Symptoms

Suspected Fault Items

Relevant Sections

Engine does not run.

1. Battery

"Starting/Charging System" in the

2.11.7

 

Diagnostic

Information and Procedures

.

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Control System JL4G18-D

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Symptoms

Suspected Fault Items

Relevant Sections

Fault Definition: When the
ignition switch in the "ST"
position, the engine crankshaft
is not rotating.

2. Starter

3. Start Relay

4. Ignition Switch

5. BCM

"Engine Immobilizer System" in the

2.5.7

 

Diagnostic

Information and Procedures

.

6. Engine Immobilizer System

Engine does not start, no sign
of the vehicle starting.
Fault Definition: When ignition
switch in the "ST" position, the
engine crankshaft rotates, but
no sign of the vehicle starting.

1. ECM Power Supply Circuit

This section

2.2.7.37

 

DTC P0560 P0562 P0563

.

2. Crankshaft Position Sensor

This section

2.2.7.29

 

DTC P0321 P0322

.

3. Camshaft Position Sensor

This section

2.2.7.31

 

DTC P0340-P0343

.

4. Ignition System

"Ignition System" in the

2.10.7

 

Diagnostic Information

and Procedures

.

5. Fuel Pump Control Circuit

"Fuel System" in the

2.3.7

 

Diagnostic Information and

Procedures

.

6. Fuel Injector Working Circuit

7. ECM

This section

2.2.8.8

 

Engine Control Module

Replacement

.

Engine difficult to start
Fault Definition: The engine
crankshaft rotation is normal,
but the vehicle can not be
started in a long time. The
engine is eventually started,
but it may stop immediately.

1. ECM Power Supply Circuit

This section

2.2.7.37

 

DTC P0560 P0562 P0563

.

2. Engine Coolant Temperature Sensor

This section

2.2.8.6

 

Engine Coolant Temperature

Sensor Replacement

.

3. Idle Air Control Valve (IAC) System

This section

2.2.8.1

 

Idle Air Control Valve

Replacement

.

4. Fuel Pump Relay, Fuel Pump, Fuel
Injector, Fuel Contamination

"Fuel System" in the

2.3.7

 

Diagnostic Information and

Procedures

.

5. Ignition System: Ignition Wire, Spark
Plug, Ignition Coil

"Ignition System" in the

2.10.7

 

Diagnostic Information

and Procedures

.

6. Excessive Engine Oil in Combustion
Chamber and Valve Seal Leakage

"Mechanical System" in the

2.6.7

 

Diagnostic

Information and Procedures

.

7. Excessive Carbon Residue in
Combustion Chamber

8. Incorrect Assembly

9. Incorrect Cylinder Compression
Pressure

Poor idle, Unstable, Inaccurate
or Stall
Fault Definition: Engine
running unstable during idle. In
extreme cases, the engine or
the vehicle will tremble. With
the throttle opening at a certain

1. ECM Power Supply Circuit

This section

2.2.7.37

 

DTC P0560 P0562 P0563

.

2. Air Cleaner Filter Blocked

---

3. Fuel Pressure Abnormal

"Fuel System" in the

2.3.7

 

Diagnostic Information and

Procedures

.

4. Fuel Contamination

5. Injector Working Abnormal

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