Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSHYUNDAI2003SANTA FE BASE, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - SELF-DIAGNOSTICS - 2.4LDIAGNOSTIC TESTSDTC P0303: CYLINDER 3 - MISFIRE DETECTEDINSPECTION/REPAIRSYSTEM INSPECTION

2003 Hyundai Santa Fe Base, Automatic

System Inspection

2003 Hyundai Santa Fe Base, AutomaticSECTION System Inspection

Check Spark Plug Cable.
1. Visually/physically inspect the following items:
  1. Damage, cracks and flashover
2. Measure the resistance of the spark plug cable.
  Specification: 5.6 kΩ/m ± 20% at 20°C 68°F)
3. Is the measured resistance within specifications?
  YES
  - Go to " 2 Check Spark Plug" as below.
  NO
  - Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check Spark Plug.
1. Remove cylinder's spark plugs.
2. Visually/physically inspect the following items:
  1. Damaged insulation, Worn electrodes, Oil or fuel fouled, Loose terminals and cracks
  2. Check for plug gap: 1.0-1.1 mm (0.039-0.043 in.)
  3. Check if the spark plug for the relevant cylinder is lighter in color than the other plugs.
3. Have a problem been found in any of the above areas?
  YES
  - Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NO
  - Go to " 3 Check Air Leakage" as below.
Check Air Leakage.
1. Visually/physically inspect the air leakage in intake/exhaust system as following items:
  1. Vacuum hoses for splits, kinks and improper connections.
  2. Throttle body gasket.
  3. Gasket between intake manifold and cylinder head.
  4. Seals between intake manifold and fuel injectors.
  5. Exhaust system between HO2S and Three way catalyst for air leakage.
2. Have a problem been found in any of the above areas?
  YES
  - Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NO
  - Go to " 4 Check for air leakage in Positive Crankcase Ventilation Valve (PCV)".
Check for air leakage in Positive Crankcase Ventilation Valve (PCV).
1. Remove PCV valve from cylinder head cover by puling ventilation hose.
2. With engine idling block PCV valve opening.
3. Verify that vacuum is felt.
4. Remove PCV valve.
5. Blow through valve from port "A" and verify that air comes out of port "B".
6. Blow through valve from port "B" and verify that no air comes out of port "A".
7. Have a problem been found?
  YES
  - Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NO
  - Go to " 5 Check Compression pressure" as below.
Check Compression pressure.
1. Warm up the engine to normal operating temperature.
2. Disconnect the spark plug cables and remove the spark plugs.
3. Crank the engine to remove any foreign material in the cylinders.
4. Put compression pressure gauge into spark plug hole.
5. Crank the engine with widely open throttle valve and check compression pressure at each cylinder.
  Specification: 1,200 kPa (12.2 kg/cm² , 170 psi)
6. Is compression pressure for each cylinder displayed within specifications?
  YES
  - Go to " 6 Check Timing belt deflection".
  NO
  - Add a small amount of oil through the spark plug hole, and repeat above steps.
    If the addition of oil causes the compression to rise, the cause is a worn or damaged piston ring or cylinder inner surface.
  - If the compression remains the same, the cause is a burnt or defective valve seat, or pressure is leaking from the gasket.
    Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check Timing belt deflection.
1. Check timing belt deflection and deflection pressure.
  Specification: Deflection: 0.2~0.27 in. (5.0~7.0 mm)
2. Is the timing belt deflection within the specifications?
  YES
  - Go to " 7 Check Timing" as below.
  NO
  - Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check Timing.
1. Ignition "OFF".
2. Check that Cam, Crank and Oil pump sprocket timing marks are correctly in alignment.
3. Engine "ON" & Monitor signal wave form from CAM and Crank shaft position Sensor are correctly in alignment.
  
  Fig 1: Monitoring Signal Waveform From Cam And Crank Shaft Position Sensor
4. Are all timing marks aligned correctly?
  YES
  - Go to " 8 Check Fuel Pressure Test" as below.
  NO
  - Repair or readjust as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Fuel Pressure Test.

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 personal injury or fire damage to vehicle components. Be cautious that Fuel is explosive and an empty fuel tank can still contain explosive gases.

Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
Install the fuel pressure gauge to the fuel pressure gauge adaptor.
Apply battery voltage to the terminal for the pump drive and activate the fuel pump: then, with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
Disconnect the vacuum hose from the pressure regulator, and plug the hose end. Measure the fuel pressure at idle.
Specification: 320~340 kPa (3.26~3.47 kg/cm² , 46~49 psi)
Measure the fuel pressure when the vacuum hose is connected to the pressure regulator.
Specification: Approx. 255 kPa (2.57 kg/cm² , 37 psi)

Are the measured fuel pressure within specifications?

YES

Go to " 9 Check injector leakage" as below.

Repair or replace according to the below table. And then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

FUEL PRESSURE SYMPTOM CHART

Condition	Possible Cause
Fuel Pressure is too low	Fuel filter, fuel pressure regulator, in-tank fuel hose or the fuel pump
Fuel Pressure is too high	Fuel pressure regulator, hose or pipe
No different fuel pressure when vacuum hose is connected or not	The vacuum hose or the nipple

Check Injector Leakage.

Ignition "OFF" after checking the Fuel Pressure Test.
Stop the engine and check for a change in the fuel pressure gauge reading for 5 minutes.

Does fuel pressure retain after engine is stopped?

YES

Substitute with a known - good PCM and check for proper operation.
If the problem is corrected, replace PCM and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Repair or replace according to the below table. And then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

FUEL PRESSURE SYMPTOM CHART

Condition	Possible Cause
Fuel Pressure reading drops slowly after engine is stopped	Injector leakage
Fuel Pressure reading drops immediately after engine is stopped	Fuel pump

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.