Engine Controls - System/component Tests Hyundai Sonata II

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC TESTING article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS W/CODES article.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

Power Circuits

With ignition off. Disconnect Electronic Control Unit (ECU) connector(s). Use a DVOM to probe ECU terminal connector. Check that battery (back-up power) voltage is present at ECU terminal A3 (White/Blue wire). Turn ignition on and ensure battery voltage is present at terminals A4 and A9 (Red wire). See appropriate wiring diagram in WIRING DIAGRAMS article. Repair circuits as required.

Ground Circuits

Connect test light to battery power. Probe ECU terminals A5 (Brown wire), A10 (Brown wire) and C13 (Brown wire) with test light. If proper ground circuit is present, test light will illuminate. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair circuits as required.

AIRFLOW SENSOR

Measure voltage between terminals No. 3 (Green/White wire on 1.5L and 2.4L, Red/Green wire on 3.0L) and No. 6 (Brown wire) of airflow sensor connector. (Scheme 29) Warm engine to normal operating temperature and slow idle, while measuring voltage between terminals No. 3 and 6. With engine at idle and at 3000 RPM, 2.7-3.2 volts should be present. If voltage is not within specification, replace airflow sensor.

Scheme 29

ATMOSPHERIC PRESSURE SENSOR

Measure voltage between terminals No. 5 (Black/Red wire) and 6 No. (Brown wire) of airflow sensor connector. (Scheme 29) Warm engine to normal operating temperature. With engine idling, gradually cover half of air cleaner intake while observing voltmeter. Voltage should drop as air intake is covered. If voltage does not drop, replace airflow sensor assembly.

COOLANT TEMPERATURE SENSOR

1. Remove coolant temperature sensor from intake manifold and place end of sensor in water. Do not allow sensor to touch container. Terminal connector portion of sensor should be .12" (3.0 mm) above water.
2. Gradually heat water and read resistance values at terminal connectors. See COOLANT TEMPERATURE SENSOR RESISTANCE table. If resistance is not within specification, replace sensor.

COOLANT TEMPERATURE SENSOR RESISTANCE

INTAKE AIR TEMPERATURE SENSOR

Disconnect airflow sensor connector. Check intake air temperature sensor by measuring resistance between terminals No. 4 (Green/Blue wire) and No. 6 (Brown wire). (Scheme 29) Using a hair drier, warm the intake air temperature sensor while watching ohmmeter. Resistance value should change evenly as temperature rises. Replace airflow sensor assembly if resistance is not within specification or values do not change while warming sensor.

INTAKE AIR TEMPERATURE SENSOR RESISTANCE

IDLE SWITCH (3.0L)

1. Idle switch contacts are part of TPS switch. Disconnect TPS sensor connector. Check for continuity between terminal No. 1 (Yellow/Red wire) and ground. (Scheme 30)for terminal location.
2. With accelerator pedal released, continuity should exist. With accelerator depressed, no continuity should exist. Replace ISC servo assembly if continuity is not as indicated.

Scheme 30

IDLE SWITCH (1.5L & 2.4L)

See ISC MOTOR under IDLE CONTROL SYSTEM.

THROTTLE POSITION SENSOR

1. Disconnect throttle position sensor connector. On 1.5L and 2.4L engines, check resistance between terminals No. 1 (Brown wire) and No. 3 (Green/Red wire). (Scheme 31) On 3.0L engines, check resistance between terminals No. 2 (Brown wire) and No. 3 (Green/Yellow wire). Resistance should be 3500-6500.
2. On 1.5L and 2.4L engines, attach ohmmeter between terminals No. 1 (Brown wire) and No. 2 (Light Green/Yellow wire). On 3.0L engines, No. 2 (Brown wire) and No. 4 (Light Green/Yellow wire). Operate throttle valve from closed to wide open throttle. Ensure resistance changes smoothly throughout entire range. Resistance should change from 500 ohms to approximately 3500-6500 ohms. If not within specification, replace TPS.

Scheme 31

MOTOR POSITION SENSOR (1.5L & 2.4L)

1. Connect ohmmeter between terminals No. 1 (Brown wire) and No. 3 (Green/Red wire) of motor position sensor connector. (Scheme 32) Measure resistance between terminals No. 1 (Brown wire) and No. 3 (Green/Red wire) of motor position sensor. Resistance should be 4000-6000 ohms.
2. Connect ohmmeter between terminals No. 1 (Brown) and No. 2 (Light Green/Yellow wire) of motor position sensor. Connect 6 volts DC (four 1.5-volt DC batteries) between terminals No. 1 (Blue/Yellow wire) and No. 2 (Blue/White wire) ISC motor connector to operate ISC motor.
3. Ensure motor position sensor resistance changes smoothly as motor extends and retracts. Resistance should change from 500 ohms to approximately 4000-6000 ohms. If resistance is not within specification, replace ISC motor assembly.

Scheme 32

NO. 1 CYLINDER TDC SENSOR

1. Disconnect crankshaft angle sensor connector. (Scheme 33) Measure output voltage between terminals No. 1 (Brown wire/ground) and No. 2 (Green wire/crank angle signal) and terminals No. 1 (Brown wire/ground) and No. 4 (Red wire/No. 1 TDC signal) while cranking engine. On 1.5L and 2.4L engines, voltage between terminals No. 1 and No. 2 should be should be 1.8-2.5 volts. On 3.0L engines, voltage should be 2.0-2.5 volts.
2. On 1.5L and 2.4L, voltage between terminals No. 1 (Yellow wire) and No. 4 (Red wire) should be 1.8-2.5 volts and the meter should fluctuate as motor is cranked. On 3.0L engines, voltage should be.2-1.2 volts and reading should fluctuate as motor is cranked. If voltage is not within specification, check sensor power and ground circuit. If sensor power and ground circuits are okay, replace No. 1 cylinder TDC sensor.

Scheme 33

Scheme 34

OXYGEN SENSOR

Warm engine to operating temperature. Remove oxygen sensor connector and connect digital voltmeter across connector terminals. Increase engine speed, while watching voltmeter. Voltage should increase from .2 to .9 volt with increase in RPM. If voltage does not increase as indicated, replace oxygen sensor.

VEHICLE SPEED SENSOR REED SWITCH

Connect an ohmmeter across reed switch terminals and rotate speedometer cable. Ensure ohmmeter reading fluctuates between continuity and no continuity as speedometer shaft is rotated.

CONTROL RELAY (1.5L & 2.4L)

1. Remove control relay, located under left side of dashboard, near instrument panel. Using an ohmmeter, check continuity between relay terminals No. 1 and No. 4. (Scheme 35) If no continuity is present, go to next step. If continuity is present, control relay is defective.
2. Check continuity between terminals No. 3 and No. 8, then No. 2 and No. 8. Approximately 95 ohms resistance should be present. Check continuity between terminals No. 6 and No. 7. Approximately 35 ohms resistance should be present. Check continuity between terminals No. 5 and No. 7, then reverse leads. Continuity should exist in one direction only. If relay does not perform as indicated, relay is defective.
3. Apply battery voltage across terminals No. 6 (positive) and No. 7 (negative) while checking continuity between terminals No. 1 and 4. If continuity is present, relay is okay. If not, replace relay.
4. Apply battery voltage across terminals No. 5 (positive) and No. 7 (negative) while checking continuity between terminals No. 1 and 2. If continuity is present, relay is okay. If not, replace relay.

Scheme 35

CONTROL RELAY (3.0L)

1. Remove control relay, located under right side of dashboard, near blower motor housing. Using an ohmmeter, check continuity between relay terminals No. 3 and 4. Then No. 1 and 6. (Scheme 36) If no continuity is present, go to next step. If continuity is present, control relay is defective.
2. Check continuity between terminals No. 3 and 9. Approximately 95 ohms resistance should be present. Check continuity between terminals No. 7 and 10. Approximately 35 ohms resistance should be present. Check continuity between terminals No. 6 and 8, then reverse leads. Continuity should exist in one direction only. If relay does not perform as indicated, relay is defective.
3. Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. If continuity is present, relay is okay. If not, replace relay.
4. Apply battery voltage across terminals No. 6 (positive) and No. 8 (negative) while checking voltage on No. 1 and 2. If battery voltage is present, relay is okay. If not, replace relay.

Scheme 36

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING article.

Fuel Injectors

1. Using a stethoscope, listen for fuel injector operation during idle or cranking. The sound should be produced at shorter intervals as engine speed increases. Ensure the sound from an adjacent injector is not mistaken as the sound of an inoperative injector.
2. Turn off engine and disconnect fuel injector connectors. Using an ohmmeter, measure resistance between fuel injector terminals. At 68°F (20°C), resistance should be 13-16 ohms.

ISC MOTOR (1.5L & 2.4L)

1. Disconnect ISC motor connector. Check motor coil continuity between terminals No. 1 and 4. (Scheme 32)for terminal location. Resistance should be 5-35 ohms. If resistance is zero ohms or far more than specification, an open or short exists in motor coil. Replace ISC servo assembly.
2. Connect 6 volts DC (four 1.5-volt DC batteries) between terminals No. 1 and No. 4 of ISC motor connector to operate ISC motor. DO NOT apply more than 6 volts. If motor does not operate, replace ISC motor assembly.

ISC SERVO STEPPER MOTOR (3.0L)

1. Measure resistance between terminals No. 2 and No. 3, then No. 2 and No. 5. The resistance should be 28-33 ohms. Measure resistance between terminals No. 5 and No. 4, then No. 5 and 6. Resistance should be 28-33 ohms. see scheme 9
2. To check stepper motor operation, remove 6-terminal ISC stepper motor connector. Apply approximately 6 volts (from a separate power supply) to ISC motor terminals No. 2 and No. 5. Connect negative lead of 6-volt power supply to terminals No. 1 and No. 4, then No. 3 and No. 4, then No. 3 and No. 6, and, finally, No. 1 and No. 6. If stepper motor moves as voltage is applied to each of the 2 terminals, the stepper motor is operating correctly.

Note. For basic ignition checks, see BASIC TESTING article.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

1. Disconnect Green-striped hose from throttle body and connect hand-held vacuum pump to hose end. Plug nipple where hose was connected to throttle body. When engine is 140°F (60°C) or less and at idle, apply vacuum to disconnected hose. If idle does not change and vacuum bleeds down, system is okay.
2. When engine is 158°F (70°C) or more and at idle, apply 2 inches Hg. If idle does not change and vacuum holds, system is okay.
3. Using a vacuum pump, apply 6.8 inches Hg. If idle becomes unstable or engine stalls (and vacuum holds), system is okay.

EGR Control Solenoid Valve (California)

1. Label and disconnect vacuum hoses and wiring harness from solenoid valve. Connect a hand-held vacuum pump to vacuum nipple where Green-striped vacuum hose was connected.
2. Apply battery voltage to one terminal of solenoid and ensure vacuum does not hold. While applying battery voltage to one terminal and grounding the other, ensure vacuum holds.
3. Using an ohmmeter, measure resistance between solenoid valve terminals. At room temperature, resistance should be 36-44 ohms. Replace solenoid if resistance is not within specification.

EGR Thermovalve (Federal)

Disconnect vacuum hoses from thermovalve and connect a hand-held vacuum pump to thermovalve nipple. Vacuum should not hold at 122°F (50°C) and should hold at 176°F (80°C).

EGR Valve

1. Remove EGR valve and check for sticking, carbon deposits and damage. Clean with solvent (if necessary).
2. Connect a hand-held vacuum pump to EGR valve. Apply maximum amount of vacuum to keep EGR valve closed. See EGR VALVE SPECIFICATIONS table. Ensure air does not flow through EGR ports of valve.
3. Apply specified EGR valve opening vacuum. See EGR VALVE SPECIFICATIONS table. Ensure air flows through EGR ports of valve. Replace valve if necessary.

EGR VALVE SPECIFICATIONS

System Test

1. Disconnect Red-striped vacuum hose between throttle body and purge control solenoid valve at throttle body. Connect a hand-held vacuum pump to disconnected vacuum hose. Plug nipple on throttle body where vacuum hose was removed.
2. With engine temperature at 140°F (60°C) or less and engine idling, apply 14 in. Hg. Vacuum should hold. Raise engine speed to 3000 RPM and again apply 14 in. Hg. Vacuum should hold.
3. With engine coolant temperature at 158°F (70°C) or more and engine idling, apply 14 in. Hg. Vacuum should hold. Turn engine off. Start engine and within 3 minutes of starting engine, apply vacuum. Vacuum should bleed down.
4. With engine running for more than 3 minutes after starting, raise engine speed to 3000 RPM and apply 15 in. Hg. Vacuum should hold momentarily and then bleed down.

Purge Control Solenoid Valve

1. Disconnect Red-striped vacuum hose from purge control solenoid valve and detach harness connector. Connect vacuum pump to nipple where Red-striped vacuum hose was present. Apply vacuum and battery voltage to valve. With battery voltage applied, vacuum should release. With battery voltage disconnected, vacuum should hold.
2. Using an ohmmeter, measure resistance between solenoid valve terminals. At 68°F (20°C), resistance should be 36-44 ohms.

PCV VALVE

Remove PCV valve. Plunger should rattle freely when valve is shaken.