Daewoo Matiz (2003 year). Manual - part 50

 

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Daewoo Matiz (2003 year). Manual - part 50

 

 

1F – 110  ENGINE CONTROLS

DTC P0172 – Fuel Trim System Too Rich

Step

Action

Value(s)

Yes

No

1

Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the system check complete?

–

Go to Step 2

Go to

“On-Board
Diagnostic

System Check”

2

Install the scan tool to the Data Link Connector
(DLC).
Turn the ignition ON.
Are any component related Diagnostic Trouble
Codes (DTCs) set?

–

Go to

Applicable DTC

table

Go to Step 3

3

1. With the engine running, operate the vehicle until

the LOOP STATUS indicates closed.

Is the Long Term Fuel Trim value above the
specified value?

30%

Go to Step 4

Go to Step 5

4

1. Turn the ignition switch ON, with the engine OFF.
2. Review the Freeze Frame data and note the

parameters.

3. Operate the vehicle within the Freeze Frame

conditions and Conditions for Setting The DTC as
noted.

Does the Long Term Fuel Trim value above the
specified value while operating under the specified
conditions?

30%

Go to Step 21

Go to Step 5

5

Visually/physically check the air cleaner filter for
excessive dirt or being  plugged and repair as
needed.
Is the repair complete?

–

Go to Step 21

Go to Step 6

6

Visually/physically check the air intake system  for
collapsed or restricted and repair as needed.
Is the repair complete?

–

Go to Step 21

Go to Step 7

7

Inspect the throttle body inlet for damaged or foreign
objects which may partially block the airflow and
repair as needed.
Is the repair complete?

–

Go to Step 21

Go to Step 8

8

1. Turn the ignition OFF.
2. Inspect the throttle bore, throttle plate and Idle Air

Control (IAC) passages for clocking and foreign
objects and repair as needed.

Is the repair complete?

–

Go to Step 21

Go to Step 9

9

Start the engine with the vehicle in park or neutral
and A/C off and note the idle quality.
Is a low or unsteady idle being experienced?

–

Go to Step 10

Go to Step 12

10

Idle the engine.
Are the IAC counts below the specified value?

100

Go to Step 12

Go to Step 11

11

1. Turn the ignition OFF.
2. Disconnect the Manifold Absolute Pressure

(MAP) sensor electrical connector.

3. Start the engine.
4. Operate the vehicle in Closed Loop while

monitoring the Long Term Fuel Trim value.

Does the Long Term Fuel Trim value increase above
the specified value?

30%

Go to Step 20

Go to Step 12

ENGINE CONTROLS  1F – 111

DTC P0172 – Fuel Trim System Too Rich (Cont’d)

Step

Action

Value(s)

Yes

No

12

Check the IAC valve performance. Refer to “DTC
P0506 Idle Speed RPM Lower Than Desired Idle
Speed” or “DTC P0507 Idle Speed RPM Higher
Than Desired Idle Speed” in this section and repair
as necessary.
Is the repair complete?

–

Go to Step 21

Go to Step 13

13

1. Disconnect the vacuum hose from the fuel

pressure regulator and inspect the hose for the
presence of fuel.

2. If fuel is presence in the vacuum hose, replace

the fuel pressure regulator.

Is the repair complete?

–

Go to Step 21

Go to Step 14

14

1. Turn the ignition ON.
2. Slowly press the acceleration pedal.
Does the Throttle Position (TP) sensor display
increase steady and evenly from its minimum
voltage at closed throttle to its maximum voltage at
Wide-Open Throttle (WOT).

–

Go to Step 15

Go to Step 19

15

1. Perform the Fuel System Diagnosis.
2. If the table isolate a problem, repair as needed.
Is the repair complete?

–

Go to Step 21

Go to Step 16

16

1. Perform the Evaporative Emission (EVAP)

Control System Diagnosis.

2. If the table isolate a problem, repair as needed.
Is the repair complete?

–

Go to Step 21

Go to Step 17

17

1. Perform the Fuel Injector balance Test.
2. If the table isolate a problem, repair as needed.
Is the repair complete?

–

Go to Step 21

Go to Step 18

18

1. Remove the Oxygen Sensor (O2S)
2. Visually/physically inspect the O2S for silicone

contamination.

3. Note: this will be indicated by a powdery white

deposit on the portion of the O2S exposed to the
exhaust stream.

4. If contamination is present on the O2S, find the

source and repair as needed.

Is the repair complete?

–

Go to Step 21

Go to

“Diagnostic

Aids”

19

1. Check the TP sensor mounting screws.
2. If they are too loose or missing tighten or replace

them as needed.

3. If the screws are OK, replace the TP sensor.
Is the repair complete?

–

Go to Step 21

–

20

1. Turn the ignition OFF.
2. Replace the MAP sensor.
Is the repair complete?

–

Go to Step 21

–

1F – 112  ENGINE CONTROLS

DTC P0172 – Fuel Trim System Too Rich (Cont’d)

Step

Action

Value(s)

Yes

No

21

1. Using the scan tool, clear the Diagnostic Trouble

Codes (DTCs).

2. Start the engine and idle at normal operating

temperature.

3. Operate the vehicle within the Conditions for

setting this DTC as specified in the supporting
text.

Does the scan tool indicate that this diagnostic has
run and passed?

–

Go to Step 21

Go to Step 2

22

Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?

–

Go to

applicable DTC

table

System OK

ENGINE CONTROLS  1F – 113

BLANK

 

 

 

 

 

 

 

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