GENERAL DESCRIPTION

In order to provide the best possible combination of drivability, fuel economy and emission control, the ECM uses a closed loop air/fuel metering system. The ECM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The ECM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The ECM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the amount reaches excessive levels because of a lean or rich condition.

DTC DESCRIPTION

Checking air-fuel ratio correction value every 0.75 sec. at idle, if the value within the detecting condition for more than 0.3 sec., PCM sets P2187. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

●

Fuel Trim Idle Condition Option Limits Exceeded

●

Sensors related to Fuel Trim

●

Intake system

●

Fuel Pressure

●

Faulty PCM

Enable Conditions

●

550rpm ≤ Engine Speed ≤ 4000rpm

●

60℃ (140℉) ≤ Engine coolant temperature ≤ 114.992℃ (239℉)

●

-10℃ (14℉) ≤ Intake Air Temperature ≤ 60℃ (140℉)

●

0° ≤ Throttle Position ≤ 72°

●

25kPa ≤ Engine Load ≤ 90kPa

●

1.5g/s ≤ Intake Air Flow ≤ 80g/s

●

Barometric Pressure ≥ 72kPa

●

Vehicle Speed ≤ 130km/h

●

System Voltage ≥ 11V

●

Closed Loop Active

●

Other diagnostic fault not active

Threshold value

●

Average of short term fuel trim 〉1.5

●

Average of long term fuel trim 〉0.76

Diagnosis Time

●

Continuous

(More than 0.375sec. Failure for every 0.75sec. Test)

MIL On Condition

●

2 Driving Cycles

MONITOR DTC STATUS
1.

Check DTC Status

(1)

Connect scantool to Data Link Connector(DLC).

(2)

IG "ON".

(3)

Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu

(4)

Read "DTC Status" parameter.

(5)

Is parameter displayed "Present fault"?

▶ Go to "Terminal and connector inspection" procedure.

▶ Fault is intermittent caused by poor contact in the sensor’s and/or PCM’s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

TERMINAL AND CONNECTOR INSPECTION
1.

Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

3.

Has a problem been found?

▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure

▶ Go to "System Inspection " procedure.

SYSTEM INSPECTION
1.

Check Air leakage

(1)

Check gasket is contaminated or misinstalled.

▶ Installation or any damage of Throttle body gasket

▶ Installation or any damage of the gasket between intake manifold and surge tank.

▶ Clogging of intake manifold or injectors resulting from foreign materials.

▶ Open stuck of PCSV caused by foreign materials between surge tank and PCSV.

(2)

Has a problem been found ?

▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

▶ Go to "Check Fuel Line Inspection" as follows.

2.

Check Fuel Line Inspection

(1)

Check clog, contamination and installation of each hose as follows.

▶ Check connection of each fuel line.

▶ Check damage, interference and installation of vaccum hose connected to fuel line.

▶ Check that fuel pipe in the fuel line is bent and sqeezed.

▶ Check any fuel leakage from fuel pipe in the fuel line.

(2)

Has a problem been found ?

▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

▶ Go to "Check fuel pressure" as follows.

3.

Check Fuel Pressure

note
-

Be cautious that Fuel is explosive and an empty fuel tank can still contain explosive gases.When working on fuel system make sure to supply adequate ventilation to the work area. Do not smoke, and keep sparks and open flames away.

-

The fuel system remains under pressure when the engine is not running. Release fuel system pressure before disconnecting any fuel line to reduce the chance of presonal injury or fire damage to vehicle components.

(1)

Start the engine and disconnect the fuel pump relay.

(2)

Wait until fuel in fuel line is exhausted and the engine stalls.

(3)

Turn the ignition switch OFF position.

(4)

Install the special service tool for measuring the fuel pressure between the delivery pipe and the fuel feed hose.

(5)

Connect the fuel pump relay.

(6)

With fuel pressure applied, check the three is no fuel leakage from the fuel pressure gauge or connection part.

(7)

Start the engine and measure the fuel pressure at idle.

Specification : 374 ~ 384 kpa (3.82 ~ 3.92 kg/㎠, 54.3 ~ 55.8psi)

(8)

Stop the engine and check for a change in the fuel pressure gauge reading.

Specification : After engine stops, the gauge reading should hold for about 5 minutes.

(9)

Is the measured fuel pressure within specification?

▶ Go to "Component Inspection" procedure.

▶ Go to "Verification of Vehicle Repair" procedure.

▶ And then, go to " Verification of Vehicle Repair" procedure, and the go to "Verification of Vehicle Repair" procedure.

Condition

Possible Cause

Suspected area

Fuel pressure too low

Clogged filter

Fuel filter

Fuel leak on the fuel-pressure regulator that is assembled on fuel pump because of poor seating of the fuel-pressure regulator

Fuel pressure regulator

Fuel pressure too high

Sticking fuel pressure regulator

Fuel pressure regulator

Fuel pressure drops slowly after engine is stopped

Injector leak

Injector

Fuel pressure drops immediately after engine is stopped

The check valve within the fuel pump is open

Fuel pump

COMPONENT INSPECTION
1.

Check PCV

(1)

IG "OFF".

(2)

Remove PCV valve and then, check that plunger in the PCV is moving.

(3)

Is the PCV normal ?

▶ Go to "Check PCSV" as follows.

▶ Substitute with a known-good PCV and check for proper operation. If the problem is corrected,replace PCV and then go to "Verification of Vehicle Repair" procedure.

2.

Check PCSV

(1)

IG "OFF".

(2)

Remove PCSV and Vaccum Hose

(3)

Check that PCSV is just one way solenoid valve

(4)

Is the PCSV normal ?

▶ Go to "Check injector" as follows.

▶ Substitute with a known-good PCSV and check for proper operation. If the problem is corrected,replace PCSV and then go to "Verification of Vehicle Repair" procedure.

3.

Check injector

(1)

IG "OFF"

(2)

Remove injector.

(3)

Check that injector hole is clogged by foreign materials.

(4)

Measure resistance between terminal 1 an 2 of injector connector.(Component Side)

Specification :

Temp.

Resistance

20℃ (68℉)

13.8 ~ 15.2Ω

(5)

Is the measured resistance within specification ?

▶ Go to "Check component related to fuel trim" as follows.

▶ Substitute with a known-good injector and check for proper operation. If the problem is corrected,replace injector and then go to "Verification of Vehicle Repair" procedure.

4.

Check component related to fuel trim

(1)

Check component related to fuel trim such as HO2S, MAFS,MAPS, TPS, ECTS, PCSV and Injectores) - Refer to each designated trouble shooting guide.

(2)

Are those component related to fuel trim O.K ?

▶ Substitute with a known-good PCM and check for proper operation. If the problem is corrected,replace PCM and then go to "Verification of Vehicle Repair" procedure.

note

There is a memory reset function on scantool that can erase optional parts automaticallydetected and memorized by PCM.

▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.

1.

Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.

2.

Using a Scantool, Clear the DTCs

3.

Operate the vehicle within conditions noted in the freeze frame data or enable conditions

4.

Monitor that all rediness test have been verified as " Complete "

5.

Are any DTCs present ?

▶ Go to the applicable troubleshoooting procedure.

▶ System is performing to specification at this time.

Яндекс.Метрика