Engine Controls - System/component Tests: Other Hyundai Sonata III

Ground Circuits

1. Turn ignition off. Using an ohmmeter, check continuity between chassis ground and ECM ground terminals. See GROUND TERMINAL IDENTIFICATION table. Ohmmeter should indicate zero ohms. If resistance is not as specified, check and repair circuit between ECM and ground.
2. Connect voltmeter negative lead to chassis ground. Connect positive lead to ECM ground terminals. See GROUND TERMINAL IDENTIFICATION table. With engine running, voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt, check for open, corrosion or loose connection in ground circuit.

Power Circuits

Turn ignition on. Check for battery voltage at ECM power terminals. See POWER TERMINAL IDENTIFICATION table. If battery voltage is not present, check operation of MFI control relay. See RELAYS.

GROUND TERMINAL IDENTIFICATION

POWER TERMINAL IDENTIFICATION

Scheme 14

Scheme 15

A/C SWITCH

Disconnect ECM connector. Turn ignition switch and A/C switch to ON position. Using a DVOM, measure voltage at ECM connector terminals No. 6 and 13. If battery voltage is present, circuit is okay. If battery voltage is not present, go to appropriate A/C SYSTEM INSPECTION procedure.

Note. If after all testing procedures have been completed, system is still inoperative, substitute ECM with known good unit and retest.

AIRFLOW SENSOR

See appropriate TESTS W/CODES article.

BAROMETRIC PRESSURE SENSOR

See appropriate TESTS W/CODES article.

COOLANT TEMPERATURE SENSOR

See appropriate TESTS W/CODES article.

CRANKSHAFT POSITION SENSOR

See appropriate TESTS W/CODES article.

EGR TEMPERATURE SENSOR

See appropriate TESTS W/CODES article.

INTAKE AIR TEMPERATURE SENSOR

See appropriate TESTS W/CODES article.

IDLE SWITCH (SONATA 4-CYLINDER)

1. Ensure switch is adjusted correctly. See ON-VEHICLE ADJUSTMENTS article. Disconnect idle switch connector. Check for continuity between terminal No. 1 (Red/Black wire) and ground. With accelerator pedal released, continuity should exist. With accelerator depressed, continuity should not exist. If continuity is not as specified, replace idle switch.
2. Measure power supply voltage from ECM to idle switch. Turn ignition on. Using DVOM, measure voltage between idle switch harness connector terminal No. 1 (Red/Black wire) and vehicle ground. Voltage should be 4 volts or more. If voltage is not within specification, turn ignition off. Inspect and repair circuit as needed.

Scheme 16

IDLE SWITCH (SONATA V6)

1. Ensure switch is adjusted correctly. See ON-VEHICLE ADJUSTMENTS article. Disconnect idle switch connector. Check for continuity between terminal No. 2 (Yellow/Red wire) and ground. With accelerator pedal released, continuity should exist. With accelerator depressed, continuity should not exist. If continuity is not as specified, replace idle switch.
2. Measure power supply voltage from ECM to idle switch. Turn ignition on. Using DVOM, measure voltage between idle switch harness connector terminal No. 1 (Yellow/Red) and vehicle ground. Voltage should be 4 volts or more. If voltage is not within specification, turn ignition off.
3. Using ohmmeter, check resistance between idle switch harness connector terminal No. 2 (Yellow/Red wire) and vehicle ground.
4. If continuity does not exist, inspect and repair circuit as needed. If continuity does exist, substitute ECM with known good unit and retest.

MOTOR (IAC/ISC) POSITION SENSOR

See appropriate TESTS W/CODES article.

NO. 1 CYLINDER TDC SENSOR

See appropriate TESTS W/CODES article.

OXYGEN SENSOR

See appropriate TESTS W/CODES article.

POWER STEERING PRESSURE SWITCH

1. Disconnect power steering pressure switch connector, located on power steering pump. Using a DVOM, check for continuity between switch and chassis ground. Continuity should not exist with wheels in straight-ahead position and engine idling. Continuity should exist when wheels are turned.
2. Using a DVOM, with ignition switch in ON position, check for battery voltage at sensor connector terminal. If battery voltage exists, circuit is okay. If battery voltage does not exist, check and repair circuit between switch connector and ECM connector terminal No. 8 (24-pin connector) on Sonata (4-cylinder), or terminal No. 21 (24-pin connector) on Sonata V6.

THROTTLE POSITION SENSOR

See appropriate TESTS W/CODES article.

TRANSAXLE RANGE SWITCH (A/T MODELS)

1. Switch is mounted to automatic transaxle, near shift lever mechanism. Ensure switch is adjusted properly. Switch output can be affected by improper adjustment. Measure power supply voltage to switch. Disconnect ECM and inhibitor switch connectors. Turn ignition switch to START position.
2. Measure voltage between vehicle ground and inhibitor switch harness connector terminal No. 11. Inhibitor switch wire color is Black/White on Sonata V6, and Yellow/Red on Sonata 4-cylinder. Voltage measured should be battery voltage. If voltage is less than battery voltage, inspect and repair power supply circuit.
3. Use DVOM and measure inhibitor switch terminal input voltage. Connect ECM connector. Ensure inhibitor switch connector is disconnected. Turn ignition switch to ON position. Measure voltage between vehicle ground and inhibitor switch harness connector terminal No. 11. Inhibitor switch wire color is Black/White on Sonata V6, and Yellow/Red on Sonata 4-cylinder. Voltage measured should be battery voltage. If voltage is less than battery voltage, inspect and repair input supply circuit.
4. On all models, use DVOM and measure input voltage of ECM. Turn ignition off. Disconnect ECM connector. Connect inhibitor switch connector. Ensure shift selector lever is in "P" position. Turn ignition switch to START position. Measure voltage between vehicle ground and ECM connector terminal. See ECM INHIBITOR SWITCH INPUT CIRCUIT IDENTIFICATION table. ECM input voltage should be 8 volts or greater. If voltage is within specification, circuit is okay. If voltage is less than 8 volts, inspect and repair circuit as necessary.

ECM TRANSAXLE RANGE SWITCH INPUT CIRCUIT IDENTIFICATION

VEHICLE SPEED SENSOR

See appropriate TESTS W/CODES article.

RELAYS

Scheme 17

1. Remove control relay, located under right side of dashboard, near blower motor housing on Sonata. Apply battery voltage across terminals No. 6 (positive) and No. 8 (negative) while checking voltage on terminals No. 1 and 2 for Sonata. (Scheme 17) Replace relay if battery voltage does not exist.
2. Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. Replace relay if continuity does not exist.
3. Apply battery voltage across terminals No. 3 (positive) and No. 9 (negative) while checking voltage on terminal No. 4. Replace relay if battery voltage does not exist.
4. Disconnect ECM connector. Turn ignition on. Using DVOM, measure voltage between ECM harness connector terminal No. 6 (10-pin connector), and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
5. Disconnect control relay harness connector. Using DVOM, measure voltage between control relay harness connector terminal No. 6 (White/Blue wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
6. Turn ignition off. Using ohmmeter, check resistance between control relay harness connector terminal No. 8 (Black/White wire on Sonata V6, Brown/White on Sonata 4-cyl.) and ECM harness connector terminals No. 12 and 15 (18-pin connector). (Scheme 14)and (Scheme 15). If continuity does not exist, inspect and repair circuits as needed.
7. Using ohmmeter, check resistance between control relay harness connector terminal No. 1 (Red wire) and ECM harness connector terminals No. 4 and 9 (10-pin connector) (Scheme 14)and (Scheme 15). If continuity does not exist, inspect and repair circuits as needed.

Scheme 18

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 18) Replace relay if battery voltage does not exist.
2. Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. Replace relay if continuity does not exist.
3. Apply battery voltage across terminals No. 3 (positive) and No. 9 (negative) while checking voltage on terminal No. 4. Replace relay if battery voltage does not exist.
4. Disconnect ECM connector. Turn ignition on. Using DVOM, measure voltage between ECM harness connector terminal No. 6 (10-pin connector) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
5. Disconnect control relay harness connector. Using DVOM, measure voltage between control relay harness connector terminal No. 6 (White/Blue wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
6. Turn ignition off. Using ohmmeter, check resistance between control relay harness connector terminal No. 8 (Black) and ECM harness connector terminals No. 16 and 17 (18-pin connector). (Scheme 15) If continuity does not exist, inspect and repair circuits as needed.
7. Using ohmmeter, check resistance between control relay harness connector terminal No. 1 (Black/Red wire) and ECM harness connector terminals No. 4 and 9 (18-pin connector). (Scheme 15) If continuity does not exist, inspect and repair circuits as needed.
8. Using ohmmeter, check resistance between control relay harness connector terminal No. 2 (Red wire) and ECM harness connector terminal No. 10 (24-pin connector). (Scheme 15) If continuity does not exist, inspect and repair circuits as needed.

POWER TRANSISTOR

See BASIC TESTING article.

FUEL DELIVERY

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

Fuel Pump

See appropriate TESTS W/CODES article.

Fuel Injectors

See appropriate TESTS W/CODES article.

IDLE CONTROL SYSTEM

Note. If after all testing procedures have been completed, system is still inoperative, substitute ECM with known good unit and retest.

IDLE AIR CONTROL MOTOR

1. Check for sound from Idle Air Control (IAC) 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 terminal No. 1. (Scheme 19) Measure resistance between terminals No. 4 and 5 and then terminal No. 6. Resistance should be 28-33 ohms at 68°F (20°C). To check stepper motor operation, remove 6-terminal IAC 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 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 19

IGNITION SYSTEM

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

EGR Valve

Remove valve and inspect for carbon deposits. Ensure valve is not sticking. Apply vacuum to valve and check for leaking diaphragm. Check airflow through valve.

EGR Control Solenoid Valve

1. Label and disconnect vacuum hoses and wiring harness from solenoid valve. Connect a hand-held vacuum pump to vacuum nipple where Red or 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.

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. Ensure air flows freely when blown through cylinder head side of PCV valve. Ensure air flows with difficulty when blown through intake manifold side of PCV valve.