13117764-13117891-13117910-13117818-13117799-13117823-13117872

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

If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The ECM sets DTC P2097 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its minimum threshold.

DTC DETECTING CONDITION

Item		Detecting Condition	Possible Cause
DTC Strategy	Case1)	● Monitoring deviation of fuel trim control (Long term)	● Three Way Catalytic Converter(TWC) ● Rear HO2S
	Case2)	● Monitoring deviation of fuel trim control (Short term)
Enable Conditions	Case1)	● No relevant failure ● Long term fuel trim active
	Case2)	● No relevant failure ● Short term fuel trim active ● Canister load ＜ 1 ● Engine coolant temperature ＞ 70℃
Threshold Value		● Deviation value of fuel trim (Short/Long trim) ＞ +25% or ＜ -25%
Diagnostic Time		● 60 sec.
Mil On Condition		● 2 Driving Cycles

SIGNAL WAVEFORM AND DATA

Scan Tool Display for HO2S

Signal Waveform ＆Data		Scan Tool Parameter
Signal Waveform ＆Data		O2 SNSR VOL.-B1/S1	O2 SNSR VOL.-B1/S2
Normal Value when circuit is normal	Idle after warm up	Signal is switching from rich(above 0.45V) to lean(below 0.45V) a minimum of 3 times in 10 seconds.	above 0.7V
HO2S(B1S1) signal circuit open		Approx. 0.43~0.45V	-
HO2S(B1S2) signal circuit open		-	Approx. 0.43~0.45V

MAPS Terminal voltage with pressure

Pressure (kPa)	Approx. 20	Approx. 35	Approx. 60	Approx. 95	Approx. 101
Voltage (V)	Approx. 0.7 ~ 0.8	Approx. 1.3 ~ 1.4	Approx. 2.3 ~ 2.4	Approx. 3.7 ~ 3.8	Approx. 3.9 ~ 4.1

Scan Tool Display for TPS

Test Condition		Scan Tool Parameter
Test Condition		TPS VOLTAGE 1
Normal value with ignition "ON" ＆engine "OFF"	Accelerator pedal released	0.20~0.47V
Normal value with engine ON ＆accelerator pedal fully depressed		4.2~4.7V
Abnormal value with ignition "ON" ＆engine "OFF"	Power circuit open	0.01V
	Ground cicuit open	4.99V
	TPS1 signal circuit open	4.99V
	TPS1 signal circuit short to ground	Approx. 0V
	TPS1 signal circuit short to battery	Above 4.99V

MONITOR DTC STATUS

note

If any DTCs relating to INJECTOR,HO2S,ECTS, or MAFS are stored, do ALL REPAIRS associated with those codes before proceeding with further troubleshooting

Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.

Press F4(DTAL) to select DTC information from the DTCs menu.

Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.

Read "DTC Status" parameter.

Is parameter displayed "History(Not Present) fault"?

note

History (Not Present) fault : DTC occurred but has been cleared.

Present fault : DTC is occurring at present time.

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

▶ Go to next step as below.

MONITOR ACTUATION TEST

note

The main purpose of this test is to identify potential engine mechanical condition problems and fuel and ignition systems problems that are not common to all cylinders. For best results, perform this test while maintaining as steady an rpm reading as possible.

warning

Before beginning tests; set the parking brake, place gear selector in P or N and block drive wheels for safety.

Warm up the engine to normal operating temperature and let it idle.

Install Scan Tool and select INJECTOR #1 parameter on the Actuation Test mode

Monitor engine rpm and shut off the injector #1 by pressing "STRT(F1)" key

Repeat procedure on all injectors and record the engine rpm.

Specification : All cylinders should show an even RPM drop.

Was each cylinder's rpm drop within the same value?

▶ Go to next step as below

▶ Cylinders with the least amount of RPM drop are not contributing their share of power.

▶ Go to "Fuel Injector Inspection" procedure and check the suspect cylinders

note

If the RPM loss between cylinders is quite large(200RPM or more) and engine has high mileage, there is possibility of engine wear. Perform compression test with pressure gauge to check the engine wear

CHECK INTAKE/EXHAUST SYSTEM FOR RESTRICTION OR LEAKAGE

Visually/physically inspect the air leakage in intake/exhaust system for the following areas:

Vacuum hoses for splits, kinks and improper connections.

Throttle body gasket

Gasket between intake manifold and cylinder head

Seals between intake manifold and fuel injectors

Exhaust system between HO2S and Three way catalyst for air leakage

Visually/physically inspect the restriction in intake/exhaust system for the following areas:

Air cleaner filter element for excessive dirt or for any foreign objects

Throttle body inlet for damage or for any foreign objects

Throttle bore and throttle plate for chocking and for any foreign objects

Restricted exhaust system

Was a problem found in any of the above areas?

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

▶ Go to next step as below

Inspect the leakage in EVAP. system for the following conditions:

(1)

Check the EVAP canister for fuel saturation. If the EVAP canister is full of fuel, visually and physically inspect the EVAP and fuel system.Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure. If OK, go to next step.

(2)

Remove the manifold side vacuum hose from the EVAP canister purge valve.

(3)

Using a hand vacuum pump apply specified vacuum(Approx. 15 in, Hg) to the manifold side of the valve

(4)

Does the valve hold vacuum?

▶ Go to next step as below

▶ Repair air leakage and go to "Verification of Vehicle Repair" procedure

SENSOR INSPECTION

note

Refer to "Signal Waveform ＆Data" in the "General Information" procedure

Visually/physically inspect the HO2S for the following conditions:

Ensure that the HO2S is securely installed.

Silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false(high) voltage signal

Fuel, engine coolant or oil contamination

Use of improper sealant

If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "Verification of Vehicle Repair" procedure.

Visually/physically inspect the MAFS for the following conditions:

Contamination or deterioration

Poor connection or damaged harness

Check for an intermittent TPS false signal. TPS signal displayed on a scantool should increase steadily when depressing accelerator pedal after starting.

Verify that the ECM ground connections are clean and properly tightened.

If test result is NG, repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

If OK, go to next step as below.

note

If the contamination is evident on the HO2S or MAFS. Fix the source of the sensor contamination before replacing the sensor to prevent future contamination.

Positive Crankcase Ventilation System Inspection

Check the engine oil level. The oil level should be between the min. and max. marking. Fill to the correct oil level

Check crankcase ventilation valve for improper installation, damaged o-rings and malfunctioning .

Warm up the engine to normal operating temperature

Connect Scantool and note the "SHORT TERM FUEL-B1" parameter on the Scantool data list.

Disconnect and plug the positive crankcase ventilation at the intake manifold side

Monitor the "SHORT TERM FUEL-B1" parameter on the Scantool data list once again.

Specification : The value should remain more or less unchanged

Is the displayed value within the specified value?

▶ Go to next step as below

▶ Check the PCV(Positive Crankcase Ventilation) valve for operation properly. Refer to "EM" group in Workshop Manual. If OK, check that engine oil is diluted with fuel. Change the oil or filter as necessary and go to "Verification of Vehicle Repair" procedure

FUEL SYSTEM INSPECTION

Fuel Line Pressure Inspection

(1)

Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.

(2)

Install a fuel pressure gage

(3)

Inspect fuel pressure with normal idle status

Specification : 338~348kPa(3.45~3.55kg/㎠)

(4)

Is fuel pressure within the specified value?

▶ Go to next step as below

▶ Inspect the suspected area. Refer to table as below. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

Condition	Possible Cause	SuspectedArea
Fuel Pressure too low	Clogged fuel filter	Fuel filter
Fuel Pressure too low	Fuel leak on the fuel-pressure regulator that is assembled on fuel pump	Fuel Pump(Fuel Pressure Regulator)
Fuel Pressure too High	Sticking fuel pressure regulator	Fuel Pump(Fuel Pressure Regulator)

Fuel Pressure Hold Inspection

(1)

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

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

(2)

Is fuel pressure within the specified value?

Visually/physically inspect the engine mechanical problem for the following:

Worn cylinder

Worn valve

Worn piston or piston ring

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

Inspect the suspected area. Refer to table as below. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

Condition	Possible Cause	Suspected Area
Fuel pressure drops slowly	Injector leak	Injector
Fuel pressure drops immediately	Stuck open in check valve of the fuel pump	Fuel pump

VERIFICATION OF VEHICLE REPAIR

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

Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.

Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.

Read "DTC Status" parameter.

Is parameter displayed "History(Not Present) fault"?

▶ System performing to specification at this time. Clear the DTC

▶ Go to the applicable troubleshooting procedure.