Chery QQ6 (S21) / S12LHD. Manual — part 215

12.10 Unsteady Idle Speed or Extinguish with Load (A/C etc.)

Yes

Remove the failure

displayed

1

Put the ignition switch to “ON”. Use a failure

diagnostic tester to check if any failure

information record exists.

No

Next step

Yes

Next step

2

Turn on A/C switch, connect an adaptor

between ECU and harness, and then measure

75# pin of ECU to see if input signal is present

(high potential signal loaded by A/C switch

through high and low voltage switches).

No

Check and repair air

conditioning circuit

Yes

Next step

3

Check if the pressure of air conditioning system,

the electromagnetic clutch of compressor and

the air conditioning pump are in right

conditions.

No

Repair or replace

Yes

Next step

4

Check the voltage on 64#, 65#, 66# and 67#

pins of ECU (for control of DC motor) as well

as corresponding pins on valve body is normal.

No

Check

controlling

circuit

Yes

Check the electric

throttle body

5

Remove electronic throttle body and check if

throttle is locked or is dumb to run.

No

Next step

Yes

Replace ECU

6

Start engine, turn on A/C, use a failure diagnosis

tester to read such signals as air intake flow and

engine revolution and check if engine

acceleration occurs.

No

Replace

the

electronic

throttle

body

Note: 75# pin is the up level request signal. When turning on A/C switch, an up level
signal will be sent to ECU through this pin, and then ECU will further check other
systems of A/C. If all systems are normal, ECU will control A/C relay to ground and
A/C system will start to work. 60# pin of ECU is medium voltage signal input; when
high potential signal is loaded on this pin, cooling fan will start and run at high speed.

12.11 Periodic Unsteadiness (Have to Perform Self-study again after ECU

is Power off)

Yes

Remove the failure

displayed

1

Put the ignition switch to “ON”. Use a failure

diagnostic tester to check if any failure

information record exists.

No

Next step

Yes

Next step

2

Check the air cleaner and look if it is open.

No

Replace

Yes

Next step

3

After starting successfully, check if air intake

consumption of the engine at idle speed is around

300Kg/h (remember to check if cylinder pressure

is normal).

No

Check and repair

air intake and leak

Yes

7

4

Let engine run at idle speed, spark out cylinder in

turn, and observe if engine revolution will fall and

fluctuate (it is prohibited to carry out spark out

experiment by disconnecting ignition cable).

No

Next step

Yes

Next step

5

Turn on ignition switch, connect an adaptor

between ECU and harness, and then check if the

voltage between 17# and 42# pins of ECU,

between 39# and 17# pins of ECU (signal output

terminal of intake air temperature sensor and

coolant temperature sensor) as well as 64#, 65#,

66#, 67# pins of ECU (for control of DC motor) is

normal.

No

Repair or replace

cable

Yes

Next step

6

Let engine run at idle speed, after coolant

temperature reaches normal value, then use a

diagnostic tester to check if ignition advance angle

of the system is normal.

No

Check other part

Yes

Sweep

7

Check air intake system for such failures that may

affect working of engine as blocking and air leak

etc.

No

Next step

Yes

Replace fuel

8

Check if fuel is deteroprated or moisture.

No

Next step

Yes

Next step

9

Use a special joint to directly provide a 12V

power supply and intermittent ground wire from

battery to injector and check if the injector can

work intermittently.

No

Check and repair

oil

injector

and

related wires

Yes

Next step

10

Check if the resistance values of cylinders’

ignition cable are normal.

No

Replace

Yes

Replace

11

Check if the ignition coil is damaged or cracked.

No

Next step

Yes

Replace ECU

12

Check if the spark plug is in right conditions.

No

Replace spark plug

Note: For periodic unsteadiness, mainly check air intake system for air leak or
electronic throttle body for failure. Following are the steps for inspection of electronic
throttle body: while turning on ignition key, throttle may jiggle; during self-checking
procedure, throttle should act with actions of accelerator pedal.

12.12 Too High Idle Speed (Have to Perform Self-study again after ECU is

Power off)

Yes

Remove the failure

displayed

1

Put the ignition switch to “ON”. Use a failure

diagnostic tester to check if any failure

information record exists.

No

Next step

Yes

Adjust or replace

2

Check if throttle valve plate is locked and if

failure exists in electronic throttle body.

No

Next step

Yes

Repair or replace

3

Check if the canister control valve, the fuel

pressure

regulator,

the

positive

crankcase

ventilation vacuum pipe and the vacuum pipe of

brake system are mounted steadily or they are

damaged.

No

Next step

Yes

Next step

4

Run the engine at idle speed and use neutral. Step

on the accelerator and observe if the idle speed is

too high.

No

6

Yes

Repair or replace

the vacuum booster

5

Clamp the vacuum pipe and observe if the idle

speed becomes normal.

No

Next step

Yes

Replace PVC valve

6

Replace PVC valve and clamp the positive

crankcase ventilation vacuum pipe. Observe if the

idle speed becomes normal.

No

Next step

Yes

Replace the canister

control valve

7

Clamp the canister control valve pipe and observe

if the idle speed becomes normal.

No

Next step

Yes

Repair or replace

8

Check if electronic throttle body is dumb or

locked.

No

Next step

Yes

Repair or replace

9

Check other parts of air intake pipe for leakage.

No

Next step

Yes

Next step

10

Check if the gasket of fuel injector is in good

condition.

No

Replace the gasket

Yes

Replace ECU

11

Check air intake system for air leak and air flow

meter for normal working.

No

Replace the sensor

Note: Check if the system goes through self-study, if not, the system will be under
failure mode or an uncertain state all the time, which may result in too high idle speed
of engine. The other cause is air leak in the system, if air leakage in the system is too
large and exceeds regulation and control range of ECU, idle speed fluctuation may
occur.