Engine Controls - System/component Tests Hyundai Elantra I

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in SELF-DIAGNOSTICS article.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests using 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.

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 airflow sensor terminals No. 4 (Green/Blue wire on 1.5L and 1.6L; Green/Brown wire on 2.0L and 3.0L) and No. 6 (Black wire). (Scheme 30) Using a hair dryer, warm 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 sensor is warmed. See INTAKE AIR TEMPERATURE SENSOR RESISTANCE table.

INTAKE AIR TEMPERATURE SENSOR RESISTANCE

IDLE SWITCH (1.5L)

Disconnect idle switch connector. Check for continuity between terminal No. 3 (Yellow/Green wire) and ground. (Scheme 31) With accelerator pedal depressed, continuity should not exist. With accelerator pedal released, continuity should exist. If continuity is not correct, replace idle switch.

Scheme 30

IDLE SWITCH (1.6L, 2.0L & 3.0L)

1. Disconnect Idle Switch connector. Check for continuity between terminal No. 1 (Yellow/Green wire on 1.6L; Red/Black wire on 2.0L and 3.0L) and ground. (Scheme 32)
2. With accelerator pedal released, continuity should exist. With accelerator depressed, no continuity should exist. If continuity is not correct, replace idle switch.

Scheme 31

THROTTLE POSITION SENSOR

1. Disconnect throttle position sensor connector. On 1.5L, 1.6L and 2.0L, measure resistance between terminals No. 1 (Black wire) and No. 4 (Green/Red wire); on 3.0L, measure resistance between terminals No. 2 (Black wire) and No. 3 (Green/Red wire). (Scheme 33)or (Scheme 34). Resistance should be 3500-6500 ohms.
2. On 1.5L, 1.6L and 2.0L, use an analog ohmmeter to measure resistance between terminals No. 1 (Black wire) and No. 3 (Light Green/Yellow wire on 1.5L and 1.6L; Green/White on 2.0L). On 3.0L, measure resistance between terminals No. 2 (Black wire) and No. 4 (Green/Red wire). Slowly operate throttle valve from closed to wide open throttle.
3. Ensure resistance changes smoothly throughout entire range. Resistance should change from 500 ohms to 3500-6500 ohms. If resistance is not within specification, replace TPS.

Scheme 32

Scheme 33

MOTOR POSITION SENSOR (1.5L)

1. Disconnect motor position sensor connector. (Scheme 35) Connect ohmmeter, and measure resistance between terminals No. 4 (Black wire) and No. 5 (Green/Yellow wire). Resistance should be 3500-6500 ohms. CAUTION: Apply only 6 volts DC or less to ISC motor connector. Higher voltage could cause ISC motor gears to lock up.
2. Disconnect Idle Speed Control (ISC) motor connector. Connect 6 volts DC (four 1.5-volt DC batteries) between terminals No. 1 (Blue/Yellow wire) and No. 2 (Blue/White wire) of ISC motor connector to operate ISC motor.
3. Measure resistance between terminals No. 2 (Light Green wire) and No. 4 (Black wire) of motor position sensor connector. Ensure motor position sensor resistance changes smoothly as motor extends and retracts. Resistance should change from 500 ohms to 3500-6500 ohms. If resistance is not within specification, replace ISC motor assembly.

Scheme 34

NO. 1 CYLINDER TDC SENSOR (1.5L)

1. Disconnect crankshaft angle sensor connector. While cranking engine, measure output voltage between terminals No. 1 (Black wire - ground) and No. 2 (Green wire - crank angle signal) and between terminals No. 1 (Black wire - ground) and No. 3 (Yellow wire - No. 1 TDC signal). (Scheme 36)
2. Voltage between terminals No. 1 and No. 2, and terminals No. 1 and No. 3, should fluctuate between 0.5 and 5.0 volts while engine is cranking. 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 35

NO. 1 CYLINDER TDC SENSOR (1.6L & 2.0L)

1. Disconnect crankshaft angle sensor connector. While cranking engine, measure voltage between terminals No. 3 (Yellow wire - crank angle signal) and No. 2 (Black wire - ground) and between terminals No. 2 (Black wire -ground) and No. 3 (Green wire on 1.6L or White wire on 2.0L - No. 1 TDC signal). (Scheme 36)
2. Voltage should fluctuate between 0.5 and 5.0 volts while engine 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.

NO. 1 CYLINDER TDC SENSOR (3.0L)

1. Disconnect crankshaft angle sensor connector. (Scheme 36) While cranking engine, measure voltage between terminals No. 1 (Yellow wire - crank angle signal) and No. 2 (Black wire - ground) and between terminals No. 2 (Black wire - ground) and No. 4 (White wire - No. 1 TDC signal).
2. Voltage should fluctuate between 0.5 and 5.0 volts while engine is cranking. 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.

OXYGEN SENSOR (1.5L)

Warm engine to operating temperature. Remove oxygen sensor connector, and connect digital voltmeter between ground and connector terminal No. 1 (except California) or No. 2 (California). (Scheme 37)or (Scheme 38). Increase engine speed, while watching voltmeter. Voltage should increase to a minimum of.6 volt. If voltage does not increase as indicated, replace oxygen sensor.

Scheme 36

Scheme 37

OXYGEN SENSOR (1.6L, 2.0L & 3.0L)

1. Warm engine to operating temperature. Remove oxygen sensor connector, and connect digital ohmmeter across terminals No. 3 and 4. (Scheme 39) With oxygen sensor temperature at about 752°F (400°C), resistance should be 30 ohms or more.
2. Using Test Harness (09302-33000 ), apply battery voltage between terminals No. 3 and 4. (Scheme 40) Connect digital voltmeter to terminals No. 1 and 2. While repeatedly racing engine, measure voltage. Voltage should increase to at least.6 volt. If voltage or resistance is not to specification, replace oxygen sensor.

Scheme 38

Scheme 39

VEHICLE SPEED SENSOR REED SWITCH

This switch is an integral part of speedometer. 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.

RELAY CAUTION

CONTROL RELAY (1.5L)

1. Remove control relay, located under left side of dashboard, near instrument panel. Check continuity between terminals No. 3 and 8 and then terminals No. 2 and 8 using an ohmmeter. (Scheme 41) Resistance should be about 95 ohms. Check continuity between terminals No. 6 and 7. Resistance should be about 35 ohms. Check continuity between relay terminals No. 1 and 4. Continuity should not exist. If continuity exists, control relay is defective; replace control relay. If continuity does not exist, go to next step.
2. Connect a 12-volt battery across relay terminals No. 6 (positive) and No. 7 (negative). (Scheme 41) Continuity should exist between terminals No. 1 and 4. Disconnect battery from relay. Using ohmmeter check between terminals No. 1 and 3. Continuity should not exist. Check between terminals No. 7 and 5 and then reverse leads.
3. Continuity should exist in one direction only. Connect 12-volt battery across terminals No. 5 and 7. Continuity should exist between terminals No. 1 and 3. If results are not as specified, replace control relay.

Scheme 40

CONTROL RELAY (1.6L, 2.0L & 3.0L)

1. Remove control relay, located under right side of dashboard, near blower motor housing. Apply battery voltage across terminals No. 6 (positive) and No. 8 (negative) while checking voltage on terminals No. 1 and 2. (Scheme 42) If battery voltage exists, relay is okay. If battery voltage does not exist, replace relay.
2. Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. If continuity exists, relay is okay. If continuity does not exist, replace relay.
3. Apply battery voltage across terminals No. 3 (positive) and No. 9 (negative) while checking voltage on No. 3 and 4. If continuity exists, relay is okay. If battery voltage does not exist, replace relay.

Scheme 41

POWER TRANSISTOR (1.5L & 3.0L)

1. Disconnect connector from power transistor. On Excel and Scoupe, apply 3.0 volts between power transistor terminals No. 2 (negative) and No. 3 (positive). On Sonata 3.0L, apply 3.0 volts between power transistor terminals No. 1 (positive) and No. 2 (negative). (Scheme 43)
2. Check continuity between terminals No. 1 and 2 (Excel and Scoupe) or between terminals No. 2 and 3 (Sonata 3.0L). With voltage applied to terminal No. 3 (Excel and Scoupe) or No. 1 (Sonata 3.0L), continuity should exist. With voltage removed from terminal No. 3 (Excel and Scoupe) or No. 1 (Sonata 3.0L), continuity should not exist. If continuity is not as specified, power transistor is defective.

Scheme 42

POWER TRANSISTOR (1.6L & 2.0L)

1. Disconnect connector from power transistor. To check power transistor for cylinders No. 1 and 4, apply 1.5 volts between power transistor terminals No. 3 (negative) and No. 4 (positive). (Scheme 44)
2. Using analog ohmmeter, check continuity between terminals No. 3 and 5. With voltage applied to terminal No. 4, continuity should exist. With voltage removed from terminal No. 4, continuity should not exist.
3. To check power transistor for cylinders No. 2 and 3, apply 1.5 volts between power transistor terminals No. 2 (positive) and No. 3 (negative). Using an analog voltmeter, check for continuity between terminals No. 1 and 3. With voltage applied to terminal No. 2, continuity should exist. With voltage removed from terminal No. 2, continuity should not exist.

Scheme 43

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC DIAGNOSTIC PROCEDURES article.

Fuel Injectors

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

ISC DC MOTOR (1.5L)

1. Disconnect ISC motor connector. Check motor coil continuity between terminals No. 1 and 2. (Scheme 35) Resistance should be 5-35 ohms at 68°F (20°C). If resistance is zero ohms or 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 2 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 (1.6L, 2.0L & 3.0L)

1. Check for sound from stepper motor as ignition switch is turned to ON position. If no sound is heard from stepper motor, measure resistance at stepper motor between terminals No. 2 and 3 and then terminals No. 1 and 2. see scheme 16 Measure resistance between terminals No. 4 and 5 and then terminals No. 5 and 6. Resistance should be 28-33 ohms at 68°F (20°C). To check stepper motor operation, remove 6-terminal ISC stepper motor connector.
2. Connect positive lead of 6-volt battery to ISC motor connector terminals No. 2 and 5. Connect negative lead to terminals No. 1 and 4, terminals No. 3 and 4, terminals No. 3 and 6, terminals No. 1 and 6 and finally terminals No. 1 and 4. Repeat procedure in reverse sequence. If stepper motor moves as voltage is applied to each pair of terminals, stepper motor is operating correctly.

Scheme 44

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC DIAGNOSTIC PROCEDURES article.

EXHAUST GAS RECIRCULATION (EGR)

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 122°F (50°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 176-205°F (80-95°C) or more and at idle, apply 2 in. Hg. If idle does not change and vacuum holds, system is okay. Apply 7.5 in. 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, and apply vacuum.
2. While applying battery voltage to one terminal and grounding the other, ensure vacuum holds. Ensure vacuum is released when battery voltage is discontinued.
3. Using an ohmmeter, measure resistance between solenoid valve terminals. Resistance should be 36-44 ohms at 68°F (20°C). Replace solenoid if resistance is not within specification.

EGR Thermovalve (Except California)

Disconnect vacuum hoses from thermovalve, and connect a hand-held vacuum pump to thermovalve nipple. Vacuum should release at 122°F (50°C) or less. Vacuum should hold at 176°F (80°C) or more.

EGR Valve

1. Remove EGR valve and check for sticking, carbon deposits and damage. Clean with solvent (if necessary). 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.
2. 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 at idle and engine coolant temperature at 104°F (40°C) or less on 3.0L or 140°F (60°C) or less on 1.5L, 1.6L and 2.0L, apply 7.3 in. Hg vacuum. Vacuum should hold. Raise engine speed to 3000 RPM, and again apply 7.3 in. Hg vacuum. Vacuum should hold.
3. With engine at idle and coolant temperature at 176°F (80°C) or more on 3.0L or 158°F (70°C) or more on 1.5L, 1.6L and 2.0L, apply 7.3 in. Hg vacuum. vacuum should hold. Turn engine off. Start engine, and again apply vacuum, within 3 minutes of starting engine. Vacuum should bleed down.
4. With engine running for more than 3 minutes after starting, raise engine speed to 3000 RPM and apply 7.3 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 removed. 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.