Chery T21 2014 Service Manual page 169

Precautions
General service requirements
 Only digital multimeter can be used to perform inspection for engine management system.
 Use genuine components to perform service work, otherwise, the appropriate engine management system
operation cannot be guaranteed.
 Only use unleaded gasoline during servicing.
 Please observe normative service and diagnostic flowchart to perform service work.
 Never disassemble the components of engine management system during servicing.
 When holding electronic elements (ECM, sensor, etc.) during servicing, take extra care not to drop them on
the ground.
 Set up a consciousness of environmental protection and dispose of the waste effectively that is produced
during servicing.
Precautions during servicing
1. Do not causally remove any component or its connector of engine management system from its installation
position to prevent damage accidentally, or foreign matter, such as moisture, oil from entering connectors,
which will affect the normal operation of engine management system.
2. Be sure to turn ignition switch off when disconnecting and connecting connectors. Otherwise, electric
elements may be damaged.
3. When simulating hot operating condition of malfunction and performing other service work that may cause
the temperature to rise, never allow ECM temperature to exceed 80°C.
4. As the supplying pressure of fuel system is high (approximately 400 kPa), all the fuel pipes are high
pressure resistant pipe. The fuel pressure in fuel lines is still high even when engine is not running.
Therefore, be careful not to casually remove the fuel pipe during servicing; when it is necessary to service
the fuel system, discharge the pressure in fuel system before removing fuel pipe. The way to discharge
pressure is as follows:
Remove fuel pump relay, start the engine and idle it until the engine stops running by itself. Then attempt to
start the engine 2 - 3 times to ensure fuel pressure is discharged completely. The removal of fuel pipe and
replacement of fuel filter should be performed in a well-ventilated area by professional service men.
5. Do not energize electric fuel pump when removing it from fuel tank to prevent electric sparks, which will
cause a fire.
6. Running test for fuel pump is prohibited when it is empty or in water; otherwise, it will shorten the service
life. Never connect the positive and negative of fuel pump in reverse.
7. When checking ignition system, only perform spark jump test when it is necessary and the time should be
shortened as much as possible. Do not open throttle during test; otherwise, a large amount of unburned
gasoline will enter the exhaust pipe, causing damage to three-way catalytic converter.
8. As idling adjustment is performed by engine management system completely, manual adjustment is not
required. The accelerator pedal stopper screw of throttle body has been adjusted at the factory, and the
user is not allowed to change its original position.
9. Do not connect battery with its polarity reversed to prevent damage to electronic elements. This system
adopts negative ground.
10.Never remove battery cable when engine is running.
11. The positive, negative battery cables and ECM must be removed before performing welding on vehicle.
12.Do not puncture wire outer coat to detect electric signals input and output by components.
Chery Automobile Co., Ltd.
06 - SQR484F ENGINE MANAGEMENT SYSTEM
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