Chery QQ Service Manual download pdf (Page 31)

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

Blower circuit malfunction (fuse is burnt, relay

circuit is open circuit or short circuit)

Irregular pressure of air conditioner (much higher of

the high voltage or the much lower of the low

voltage)

Malfunction of evaporator temperature sensor

Air conditioner relay circuit is failure (short circuit

to ground, short circuit to power supply, open

circuit).

4 ME7 SYSTEM TESTAND REPAIR ACCORDING TO TDC

Explanation:

1. When it is confirmed that malfunction is steady we can carry out the test and repair as

below, otherwise this will cause wrong diagnosis.

2. There is multimeter mentioned below, it is referred to digital multimeter; prohibit to use

finger multimeter check the EFI system.

3. Check and repair the vehicle with anti theft system please re-program the replaced ECU

when there is the occasion of changing the ECU at “flow up steps”.

4. In this items when the TDC of P0171、P0172、P0335、P0336、P1651 existing, the engine

trouble light will not light on.

5. If it shows much lower of the voltage in some circuit in DTC explanation, it refers to

perhaps there is ground short circuit inside of this circuit; If it shows much higher of the

voltage in some circuit in DTC explanation, it refers to perhaps there is power supply

short circuit inside of this circuit; If it shows circuit failure in DTC explanation, it refers

to perhaps there is open circuit or multi circuit malfunction inside of this circuit.

Diagnosis help: 1. DTC can not be deleted; it is steady failure; if it is occasional failure,

check if it is because of the loosening of cable joint.

2. Check according to the above steps and find noting wrong;

3. During check and repair pay attention that the influence of vehicle

maintenance, cylinder pressure and mechanical ignition timing to

the system;

4. Change ECU and test it. If the DTC can be deleted, the malfunction

is inside of ECU; if the DTC can not be deleted, change back to the

original ECU and check it again according to above items.

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Chery QQ Service Manual Page 31