Chery QQ6 (S21) / S12LHD. Manual — part 115

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.

12.13. Engine Revolution Speed is too Low or Flameout

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

Run the engine at idle speed and check if the

engine revolution speed is normal at idle speed.

No

Next

step,

overhaul

with

reference to idle

speed

failure

entries

Yes

Next step

4

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

Overhaul

Yes

Next step

5

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

systems

Yes

Next step

6

Connect fuel manometer valve. Short 30# and

87# pins of fuel pump relay to make the fuel

pump run, and then check if fuel pressure is

around 400kPa.

No

10

Yes

9

7

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

Next step

Yes

Next step

8

Clean out the fuel injector and look if it can

work correctly.

No

Replace

fuel

injector

Yes

Replace fuel

9

Check if fuel is bad or moisture.

No

15

Yes

Next step

10

Check if the fuel pressure value is below 350

kPa.

No

14

Yes

Next step

11

Close the fuel manometer valve. Re-engage the

ignition switch to let the fuel pump run for a

period of time, and then check if fuel pressure

can be built up.

No

13

12

Open the valve of fuel gauge and clamp the oil

return pipe by oil return baffle so that the oil can

Yes

Replace

fuel

pressure regulator

not return. Check if the oil pressure occurs

immediately.

No

Repair and replace

fuel injector and

oil pipe

Yes

Repair or replace

oil intake pipe

13

Check if there is leaking or jam in oil intake

pipe.

No

Replace oil pump

Yes

Repair or replace

oil return pipe

14

Check if the oil return pipe is bended or

jammed.

No

Replace

fuel

pressure regulator

Yes

Next step

15

Put the ignition switch to “ON”. Check if

voltage on the following pins of ECU is normal:

if it is a battery voltage around 12V on 12#, 14#,

15# pins; if the voltage between 51#, 53#, 3#,

61#, 80# pins and the wire is zero.

No

Repair or replace

cable

Yes

Replace ECU

16

Check if ignition coil, ignition cable and spark

plug are normal.

No

Adjust or replace

the parts involved

Note: This phenomenon indicates a comparatively obvious failure and some minute
details, such as if strainer of the system or exhaust pipe is blocked and so forth, should
also be checked. For other causes, check spark plug and ignition cable etc.