Chery QQ6 (S21) / S12LHD. Manual — part 117

12.16 Unable to Reach the Maximum Revolution when Accelerating

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

With engine off, check if air cleaner is smooth

(can not simply rely on visualization, remove

the air cleaner and then perform test drive again)

and if air intake system is chocked.

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

Repair in accordance

with

idle

speed

failure item

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

Put the ignition switch to “ON”. Check if it is

break or short circuit between 38#, 32#, 54#,

36# pins on ECU connector and 1#, 2#, 4#, 6#

pins of throttle position sensor of electronic

throttle valve body.

No

Repair or replace

Harness

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 is normal.

No

Check other part

Yes

Next step

7

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

11

Yes

Next step

8

Check if working positions of camshaft position

sensor and crankshaft position sensor are

normal.

No

Replace

the

parts

involved

Yes

Next step

9

Clean out the fuel injector and look if it can

work correctly.

No

Replace fuel injector

Yes

Replace fuel

10

Check if fuel is deteroprated or moisture.

No

16

Yes

Next step

11

Check if the fuel pressure value is below 300

kPa.

No

15

12

Check if the exhaust system and three-way Yes

Replace or clean

catalytic converter are jammed.

No

Replace ECU

Note: In case the engine is unable to reach its maximum revolution when accelerating, mainly check if

exhaust pipe is chocked and air cleaner is smudgy. In addition, for electric control system of A21, in case

of a failure in crankshaft or camshaft position sensor, ECU will take restrictive driving measures to

restrict engine revolution to exceed certain value, which should be noted during maintenance process.

12.17 When Releasing Accelerator Pedal after Acceleration, Unsteady Idle

Speed Occurs at Instant, even Extinguishes.

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

With engine off, check if air cleaner is smooth

(can not simply rely on visualization, remove

the air cleaner and then perform test drive again)

and if air intake system is chocked.

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

Repair in accordance

with

idle

speed

failure item

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

Put the ignition switch to “ON”. Check if it is

break or short circuit between 38#, 32#, 54#,

36# pins on ECU connector and 1#, 2#, 4#, 6#

pins of throttle position sensor of electronic

throttle valve body.

No

Repair or replace

Harness

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 is normal.

No

Check other part

Yes

Next step

7

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

11

Yes

Clear carbon deposit

8

Remove air intake hose, check if carbon deposit

or other soil (this may result in air intake system

of engine being chocked when the valve plate

closes) exists.

No

Next step

Yes

Next step

9

Clean out the fuel injector and look if it can

work correctly.

No

Replace fuel injector

Yes

Replace fuel

10

Check if fuel is deteroprated or moisture.

No

16

11

Check if the fuel pressure value is below 400 Yes

Next step

kPa.

No

15

Yes

Replace or clean

12

Check if the exhaust system and three-way

catalytic converter are jammed.

No

Replace ECU

Note: For an electric control motor with the electronic throttle body, the main actuators of its air intake

system are air flow meter and electronic throttle body. Air flow meter has very high operational reliability

and very low failure rate, while, due to particularity of road status in China and affected by operating

environment, choke is liable to occur between valve plate and valve body of the electronic throttle body,

which may obstruct air from entering the engine and result in extinguish of engine.