Engine Controls - Tests W/codes: Diagnosis Hyundai Sonata III

DIAGNOSTIC PROCEDURE

Note. Trouble codes will be recorded at various operating times. Some codes require operation of sensor or switch for 5 seconds; other components require operation for 5 minutes or longer at normal operating temperature, vehicle speed and load. Therefore, some codes may not set in a service bay operational mode and may require road testing vehicle in order to duplicate condition under which code will set.

Diagnosis of computerized engine control system should be performed in following order

1. Ensure all engine systems other than computerized systems (i.e. compression, ignition, etc.) are operating properly. DO NOT proceed with testing unless all other problems have been repaired. If MIL light is illuminated, see RETRIEVING CODES (NON-SCAN) or RETRIEVING CODES (SCAN TESTER). For diagnosing hard codes, see FAULT CODES to determine cause of malfunction. See DIAGNOSTIC TESTS for test procedures corresponding to fault codes.
2. For diagnosing intermittent codes, proceed to INTERMITTENTS in TESTS W/O CODES article. Inspect condition of system harness by conducting recommended voltage or continuity checks. See WIRING DIAGRAMS article for additional information on specific circuit configuration. Inspect condition of individual component. Repair or replace component as needed.
3. Recheck system operation after repair is made. If trouble code still is present, substitute ECM with known good unit. Verify that system is repaired. After repairs have been completed, clear trouble codes. See CLEARING TROUBLE CODES.

DIAGNOSTIC TESTS

Note. Perform all resistance and voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance, unless stated otherwise in test procedures.

Clear fault codes after each repair. See CLEARING CODES. Recheck for codes to confirm repair. See RETRIEVING CODES.

System Inspection

Determine if vehicle is producing high emissions. High emissions can be caused by faulty HO2S, injector, coolant temperature sensor, vacuum leak and/or malfunctioning airflow sensor.

Harness Inspection (Sonata 4-Cylinder)

1. Measure power supply voltage. Disconnect HO2S harness connector. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 3 and vehicle ground. (Scheme 9) If voltage is less than battery voltage, inspect and repair circuit as needed.
2. Check continuity of ground circuit to ECM. Turn ignition off. Disconnect ECM harness connector. Connect a jumper wire between ECM harness connector terminal No. 9, connector C01-1 and vehicle ground. (Scheme 8) Using ohmmeter, measure resistance between HO2S sensor harness connector terminal No. 4 and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
3. Check continuity of ground circuits. Using ohmmeter, check resistance between sensor harness connector terminal No. 1 and vehicle ground. (Scheme 9) If continuity does not exist, inspect and repair circuit(s) as needed.

Scheme 8

Heated Oxygen Sensor Inspection

1. Disconnect HO2S harness connector. Using ohmmeter, check resistance between sensor component connector terminals No. 3 and 4. (Scheme 9) Ensure engine is at normal operating temperature. Resistance should be 30 ohms or more. Replace HO2S if measurement is not within specification.
2. Connect Test Harness (09392-33000 ) to HO2S. DO NOT connect harness connector to test harness. Connect 12-volt power source to test harness. Connect 12-volt power source positive lead to White test lead and negative to Black test lead. Connect DVOM positive lead to Yellow test lead and negative lead to Green test lead.
3. Start and run engine. Rapidly accelerate engine speed from 750 RPM to 4000 RPM and back to idle several times to enrich mixture. Disconnect HO2S sensor harness connector. Using DVOM, measure sensor output. Voltage from HO2S should be.6 volt minimum. Replace HO2S if it fails testing.

Scheme 9

Inspect condition of Airflow Sensor (AFS) harness connector. A loose connection could cause intermittent stalling. Ensure there are no restrictions or clogs in air intake system.

Harness Inspection

1. Check AFS power supply voltage. Disconnect harness connector. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 2 (Red wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
2. Check AFS signal circuit to ECM. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 3 (Red/Green wire on Sonata V6, Green/White wire on all others) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is not within specification, check continuity of circuit.
3. Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM connector terminal No. 15 on Sonata V6 (Red/Green wire, 24-pin connector), terminal No. 3 on Sonata 4 - Cylinder (Green/White wire, 24-pin connector) and vehicle ground. (Scheme 8)
4. Check AFS ground circuit. Using ohmmeter, check continuity between harness connector terminal No. 6 (Black) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.

Airflow Sensor Inspection

Manufacturer does not provide separate component testing procedures.

Inspect condition of harness connector. Clean and repair as needed.

1. Check sensor ground circuit to ECM. Disconnect sensor harness connector. Using ohmmeter, check resistance between terminal No. 6 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit.
2. Check sensor signal circuit to ECM. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 4 (Green/Brown wire on Sonata 4-cylinder, Green/Black wire on Sonata V6, and ground. Voltage should be 4.5-4.9 volts. If voltage is not within specification, check continuity of circuit.
3. Turn ignition off. On all models except California Elantra and Excel, go to step 4). On California Elantra and Excel models, disconnect ECM harness connector. Connect jumper wire between ECM connector terminal No. 10 (Green/Blue wire, 22-pin connector) and vehicle ground. (Scheme 8) Using ohmmeter, check resistance between AFS harness connector terminal No. 4 (Green/Blue wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity does exist, substitute ECM with known good unit and retest.
4. On all models except California Elantra and Excel, disconnect ECM harness connector. Connect jumper wire between ECM connector terminal No. 3 (Green/Black wire, 24-pin connector) on Sonata V6 or terminal No. 5 (Green/Blue wire, 24-pin connector) on all others and vehicle ground. (Scheme 8) Using ohmmeter, check resistance between AFS harness connector terminal No. 4 (Green/Black wire on Sonata V6, Green/Blue wire on all others) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity does exist, substitute ECM with known good unit and retest.

Intake Air Temperature Sensor Inspection

Check resistance between component connector terminals No. 4 and 6. (Scheme 10) See INTAKE AIR TEMPERATURE SENSOR RESISTANCE table. Replace airflow sensor if temperature sensor is not within specifications.

INTAKE AIR TEMPERATURE SENSOR RESISTANCE

Scheme 10

Faulty Throttle Position Sensor (TPS) can cause abrupt automatic transmission shifting and poor performance.

Harness Inspection (Except Sonata V6)

1. Measure TPS power supply voltage. Disconnect TPS harness connector. Turn ignition on. Using DVOM, measure voltage between TPS harness connector terminal No. 4 (Green/Red wire) and vehicle ground. Voltage should be 4.8-5.2 volts.
2. If voltage is not within specification, turn ignition off. Disconnect ECM connector. On all models except Calif. Elantra and Excel, connect jumper wire between ECM harness connector terminal No. 14 (24-pin connector) and vehicle ground. (Scheme 8)
3. On Calif. Elantra and Excel, connect jumper wire between ECM harness connector terminal No. 1 (22-pin connector) and vehicle ground. Using ohmmeter, check resistance between TPS harness connector terminal No. 4 (Green/Red wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
4. Check continuity of TPS ground circuit. Using ohmmeter, check resistance between TPS harness connector terminal No. 1 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
5. Check continuity of output circuit between TPS and ECM. Ensure ignition is off. On all models except Calif. Elantra and Excel, connect jumper wire between ECM harness connector terminal No. 18 (Light Green/Yellow wire, 24-pin connector) and vehicle ground. (Scheme 8)
6. On Calif. Elantra and Excel, connect jumper wire between ECM harness connector terminal No. 20 (22-pin connector) and vehicle ground. Using ohmmeter, check resistance between TPS harness connector terminal No. 3 (Light Green/Yellow wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.

Harness Inspection (Sonata V6)

1. Measure TPS power supply voltage. Disconnect TPS harness connector. Turn ignition on. Using DVOM, measure voltage between TPS harness connector terminal No. 1 (Green/Yellow wire) and vehicle ground. Voltage should be 4.8-5.2 volts.
2. If voltage is not within specification, turn ignition off. Disconnect ECM connector. Connect jumper wire between ECM harness connector terminal No. 16 (24-pin connector) and vehicle ground. (Scheme 10) Using ohmmeter, check resistance between TPS harness connector terminal No. 1 (Green/Yellow wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
3. Check continuity of TPS ground circuit. Using ohmmeter, check resistance between TPS harness connector terminal No. 4 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
4. Check continuity of input circuit between TPS and ECM. Ensure ignition is off. Connect jumper wire between ECM harness connector terminal No. 18 (Light Green/Yellow wire, 24-pin connector) and vehicle ground. (Scheme 10) Using ohmmeter, check resistance between TPS harness connector terminal No. 2 (Light Green/Yellow wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.

Throttle Position Sensor Inspection

Turn ignition off. Disconnect TPS harness connector. Using ohmmeter, check resistance between TPS terminals No. 1 and 4. (Scheme 11) Resistance should be 350-650 ohms. Connect ohmmeter between TPS terminals No. 1 and 2 on Sonata V6 or terminals No. 1 and 3 on all other models. Operate throttle from closed to WOT position. Monitor ohmmeter while opening throttle. Ohmmeter needle should move accordingly with throttle movement. Replace TPS if it fails any of above tests.

Scheme 11

Ensure idle speed is within specification. See ADJUSTMENTS article. Poor ISC motor position sensor performance can be caused by dirty throttle valve, throttle valve-to-plenum vacuum leak, miscellaneous vacuum leaks, EGR valve leak and/or poor engine performance caused by malfunctions of emission, fuel or ignition system.

1. Measure power supply voltage to sensor. Disconnect Motor Position Sensor (MPS) harness connector. Turn ignition on. Using DVOM, measure voltage between MPS harness connector terminals No. 1 and 5 (Green/Red wires) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is not within specification, check continuity of circuit.
2. Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal No. 1 (Green/Red wire, 22-pin connector) and vehicle ground. (Scheme 9) Using ohmmeter, check resistance between MPS harness connector terminals No. 1 and 5 (Green/Red and Green/Yellow wires) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity does exist, substitute ECM with known good unit and retest.
3. Check continuity of ground circuit. Using ohmmeter, check resistance between MPS harness connector terminal No. 4 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
4. Check continuity of input circuit between MPS and ECM. Connect jumper between ECM harness connector terminal No. 22 (Light Green wire, 26-pin connector) and vehicle ground. Using ohmmeter, check resistance between MPS harness connector terminal No. 2 (Light Green wire) and vehicle ground. If continuity does not exist, inspect and repair wire as needed.

Idle Speed Control Motor Position Sensor Inspection

1. Check resistance between MPS terminals No. 4 (Black wire) and No. 5 (Green/Red wire). Resistance should be 350-650 ohms. Connect 6-volt power source to ISC servo motor 2-pin connector. Monitor resistance between MPS terminals No. 2 (Light Green wire) and No. 4 (Black wire). As plunger extends or retracts, resistance should change accordingly. Erratic resistance changes indicate malfunction with sensor.

Inspect condition of connector. Clean and repair as needed. Faulty Coolant Temperature Sensor (CTS) can cause incorrect idle RPM during cold start-up condition and rich air/fuel mixture.

1. Measure sensor power supply voltage. Disconnect sensor harness connector. Turn ignition on. Using DVOM, measure voltage between vehicle ground and terminal No. 2 (Yellow/Green wire on Sonata V6, Yellow/Red wire on all other models). Voltage should be 4.5-4.9 volts. If voltage is within specification, go to step 3). If voltage is not within specification, go to step 2).
2. Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between appropriate ECM harness connector terminal and vehicle ground. See CTS INPUT TERMINAL IDENTIFICATION table for ECM terminal number. Using ohmmeter, check continuity between vehicle ground and sensor harness connector terminal No. 1 (Black wire). If continuity does not exist, inspect and repair circuit. If continuity exists, substitute ECM with known good unit and retest. Go to step 3). CTS INPUT TERMINAL IDENTIFICATION (1) Application ECM Terminal No. Connector No. Wire Color Sonata 4-Cylinder 17 C01-1 Yellow/Red Sonata V6 17 C81-1 Yellow/Green (1) (Scheme 8)
3. Check continuity of sensor to ECM ground circuit. Ensure ignition is off. Using ohmmeter, check resistance between sensor harness connector terminal No. 1 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.

Coolant Temperature Sensor Inspection

Remove sensor and immerse in water. Using ohmmeter, check resistance while increasing water temperature. See COOLANT TEMPERATURE RESISTANCE SPECIFICATIONS. Replace sensor if resistance measured is not within specification.

COOLANT TEMPERATURE RESISTANCE SPECIFICATIONS

Inspect harness connector, clean and repair as needed. If tachometer is inoperative, Crankshaft Position Sensor (CKP) may be faulty. If it is determined that the CKP is out of specification but engine still runs, check for faulty coolant temperature sensor, idle air/speed control motor and/or incorrect idle speed adjustment.

1. Measure CKP power supply voltage. Disconnect sensor harness connector. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 2 (Red wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
2. Check continuity of ground circuit. Turn ignition off. Using ohmmeter, check resistance between harness connector No. 1 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
3. Check output voltage from ECM. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 4 (Green wire on Elantra, Yellow wire on Sonata 4-Cylinder) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, go to step 4).
4. Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal No. 16 (Green wire, 24-pin connector) or No. 15 (22-pin connector) and vehicle ground. (Scheme 8) Using ohmmeter, check resistance between CKP harness connector terminal No. 4 (Green wire on Elantra, Yellow wire on Sonata 4-Cylinder) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.

1. Measure CKP power supply voltage. Disconnect sensor harness connector. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 3 (Red wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
2. Check continuity of ground circuit. Turn ignition off. Using ohmmeter, check resistance between harness connector No. 2 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
3. Check output voltage from ECM. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 1 (Yellow wire) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, go to step 4).
4. Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal No. 22 (Green wire, 24-pin connector) and vehicle ground. (Scheme 10) Using ohmmeter, check resistance between CKP harness connector terminal No. 1 (Yellow wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.

CKP Sensor Inspection

Manufacturer does not provide component testing information.

Engine stalling, rough idle and/or poor acceleration could be caused by faulty Top Dead Center (TDC) sensor. Inspect harness connector, clean and repair as needed.

1. Inspect TDC sensor power supply circuit. Disconnect TDC sensor harness connector. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 3 (Red wire) on Sonata V6, No. 2 (Red wire) on all other models and vehicle ground. Voltage should be battery voltage.
2. Check continuity of ground circuit. Turn ignition off. Using ohmmeter, check resistance between sensor harness connector terminal No. 2 (Black wire) on Sonata V6, No. 1 (Black wire) on all other models and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
3. Check sensor output voltage from ECM. Turn ignition on. Using DVOM, measure voltage between TDC sensor harness connector terminal No. 4 (White wire) on Sonata V6, No. 3 (Yellow wire) on all other models and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, turn ignition off.
4. Disconnect ECM connector. Connect jumper wire between ECM harness connector terminal and vehicle ground. See TDC INPUT TERMINAL IDENTIFICATION for ECM terminal identification. Using ohmmeter, check resistance between TDC harness connector terminal No. 4 (White wire) on Sonata V6, No. 3 (Yellow wire) on all other models and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest. Top Dead Center Sensor Inspection Manufacturer does not provide individual component testing.

TDC INPUT TERMINAL IDENTIFICATION (1)

An open or short circuit in Vehicle Speed Sensor (VSS) signal circuit may cause engine to stall when vehicle is decelerating to a complete stop.

1. Check VSS power supply voltage from ECM. Disconnect VSS harness connector from back of instrument panel. Instrument panel removal may assist in accessing harness connector. Turn ignition on. Using DVOM, measure voltage between VSS harness connector terminal No. 2 (Yellow/White wire) and vehicle ground. Voltage should be 4.5-4.9 volts.
2. If voltage is within specification, circuit is okay. If voltage is not within specification, turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal No. 18 (Yellow wire, 22-pin connector) or terminal No. 19 (Yellow/White wire, 24-pin connector). (Scheme 8) Using ohmmeter, check resistance between VSS harness connector terminal No. 2 (Yellow/White wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
3. Check ground circuit of sensor. Using ohmmeter, check resistance between VSS harness connector terminal No. 1 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.

Vehicle Speed Sensor Inspection

Check output of VSS signal. Raise and support vehicle. Disconnect ECM harness connector. Using DVOM, measure voltage between ECM harness connector terminal No. 18 (Yellow wire, 22-pin connector) or terminal No. 19 (Yellow/White wire, 24-pin connector). (Scheme 8) If DVOM does not display a pulse voltage, replace VSS and retest.

Malfunctioning barometric pressure sensor can cause general poor engine performance. Ensure air filter is not clogged.

1. Check continuity of ground circuit. Ensure ignition is off. Disconnect airflow sensor connector. Using ohmmeter, check resistance between sensor harness connector No. 6 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
2. Measure sensor power supply voltage. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 1 (Green/Red wire) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, go to step 4).
3. If voltage is not within specification, turn ignition off. Disconnect ECM connector. Connect jumper wire between ECM harness connector terminal No. 14 (24-pin connector) or No. 1 (22-pin connector) and vehicle ground. (Scheme 8) Using ohmmeter, check resistance between sensor harness connector terminal No. 1 (Green/Red wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
4. Check continuity of output circuit between barometric pressure sensor and ECM. Connect jumper wire between ECM harness connector terminal No. 21 (24-pin connector) or No. 19 (22-pin connector) and vehicle ground. Using ohmmeter, check resistance between sensor harness connector No. 5 (Brown wire) and vehicle ground. If continuity does not exist, check and repair circuit as needed.

1. Check continuity of ground circuit. Ensure ignition is off. Disconnect airflow sensor connector. Using ohmmeter, check resistance between sensor harness connector No. 6 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
2. Measure sensor power supply voltage. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 1 (Green/Yellow wire) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, go to step 4).
3. If voltage is not within specification, turn ignition off. Disconnect ECM connector. Connect jumper wire between ECM harness connector terminal No. 16 (Green/Yellow wire, 24-pin connector) and vehicle ground. (Scheme 10) Using ohmmeter, check resistance between sensor harness connector terminal No. 1 (Green/Yellow wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
4. Check continuity of output circuit between barometric pressure sensor and ECM. Connect jumper wire between ECM harness connector terminal No. 24 (Blue/White wire, 24-pin connector) and vehicle ground. Using ohmmeter, check resistance between sensor harness connector No. 5 (Blue/White wire) and vehicle ground. If continuity does not exist, check and repair circuit as needed.

Barometric Pressure Sensor Inspection

Manufacturer does not provide individual component testing.

1. Determine if vehicle is difficult to start when engine is hot. Check fuel pressure. See BASIC TESTING article. Ensure there are no fuel leaks. Determine if all injectors are operating properly.
2. Inspect ECM power supply and ground circuits. Inspect MFI control relay. See SYS/COMP TESTS article. Inspect crankshaft position sensor and TDC sensor. See CODE 22 (CRANKSHAFT POSITION SENSOR) and CODE 23 (TOP DEAD CENTER SENSOR).

1. Measure injector power supply voltage. Disconnect injector harness connectors. Turn ignition on. Using DVOM, measure voltage at each injector harness connector terminal No. 1 (Black/Red wire) on Sonata V6, No. 2 (Red wire) on Sonata 4-Cylinder, No. 2 (Green/White wire) on all other models. If voltage measured is less than battery voltage, inspect and repair circuit(s) as needed.
2. Check continuity of injector ground circuit. Disconnect ECM harness connector. Ensure ignition is off. Connect a jumper wire between each injector ECM terminal and ground. Disconnect injector harness connectors. Using ohmmeter, check continuity between each injector terminal and vehicle ground. See FUEL INJECTOR GROUND CIRCUIT IDENTIFICATION table for ECM terminal numbers and wire colors.

FUEL INJECTOR GROUND CIRCUIT IDENTIFICATION

Fuel Injector Inspection

1. Check injector operation with engine running. Start engine and listen for injector operation (clicking sound). Ensure clicking sound of injector is not from adjacent injector with sound being transmitted through fuel delivery pipe. To check injector operating sound, use stethoscope or feel for vibration.
2. Check resistance between injector terminals. Disconnect injector harness connector. Using ohmmeter, check resistance. Resistance should be 13-16 ohms. Replace injector if measurement is not within specification.

Inspect all fuel hoses and electrical connectors. Clean and repair as needed.

1. Using a jumper wire, apply battery voltage to fuel pump check terminal. See BASIC TESTING article for fuel pump check terminal location. If fuel pump does not operate, go to step 2). If fuel pump operates, go to step 4).
2. Disconnect fuel pump connector. Using DVOM, check continuity between chassis ground and fuel pump connector terminal No. 2 (Black wire). If continuity does not exist, inspect and repair circuit as needed.
3. Check continuity between fuel pump harness connector terminal No. 1 (White/Black wire on Sonata, Yellow wire on all other models) and fuel pump checking terminal. If continuity does not exist, inspect and repair circuit as needed.
4. Ensure ignition is off. Disconnect ECM control relay and ECM harness connectors. Move jumper wire connected to fuel pump checking terminal to vehicle ground. Using ohmmeter, check resistance between ECM control relay harness connector terminal and vehicle ground. See ECM CONTROL RELAY TERMINAL IDENTIFICATION table. If continuity does not exist, inspect and repair circuit as needed. ECM CONTROL RELAY TERMINAL IDENTIFICATION Application Relay Terminal No. Wire Color Corresponding ECM Terminal No. Sonata 4-Cyl. 4 White/Black 24 (1) Sonata V6 4 Black/White 7 (2) (1) 24-pin connector. (2) 10-pin connector.
5. Check resistance between ECM harness connector terminal and vehicle ground. See ECM CONTROL RELAY TERMINAL IDENTIFICATION table. (Scheme 8) If continuity does not exist, inspect and repair circuit as needed.
6. Turn ignition on. Using DVOM, measure voltage between ECM control relay harness connector terminal and vehicle ground. See ECM POWER SUPPLY TERMINAL IDENTIFICATION table. Voltage should be 8 volts or more. Turn ignition switch to START position. Measure voltage between ECM control relay connector terminal and vehicle ground. See ECM POWER SUPPLY TERMINAL IDENTIFICATION table. Voltage should be 8 volts or more. If voltage is not within specification, inspect and repair circuit(s) as needed. ECM POWER SUPPLY TERMINAL IDENTIFICATION Ignition Switch Terminal No. (1) Wire Color ON Position Sonata 4-Cyl. 3 Black/White Sonata V6 3 Blue START Position Sonata 4-Cyl. 7 Black/Red Sonata V6 7 Red/Green (1) (Scheme 8)
7. Connect jumper wire between ECM harness connector terminal and vehicle ground. See ECM FUEL PUMP SIGNAL TERMINAL IDENTIFICATION table. Measure resistance between ECM control relay connector terminal and vehicle ground. See ECM FUEL PUMP SIGNAL TERMINAL IDENTIFICATION table. If continuity does not exist, inspect and repair circuit as needed.
8. Using ohmmeter, check resistance between chassis ground and ECM control relay harness connector terminal No. 7 (Black wire) on Excel, terminal No. 10 (Black wire) on all other models. If continuity does not exist, inspect and repair circuit as needed.

ECM FUEL PUMP SIGNAL TERMINAL IDENTIFICATION

Ensure EGR system vacuum hoses and electrical connectors are secure and vacuum hoses are free from leaks and restrictions.

1. Disconnect EGR temperature sensor harness connector. Turn ignition on. Using DVOM, measure voltage between EGR temperature sensor harness connector terminal No. 1 and vehicle ground. See EGR TEMPERATURE SENSOR TERMINAL IDENTIFICATION table. Voltage should be 4.3-4.7 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, turn ignition off.
2. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal and vehicle ground. See EGR TEMPERATURE SENSOR TERMINAL IDENTIFICATION table.
3. Using ohmmeter, check resistance between EGR temperature sensor harness connector terminal No. 1 and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
4. Using ohmmeter, check resistance between EGR temperature sensor connector terminal No. 2 and vehicle ground. See EGR TEMPERATURE SENSOR TERMINAL IDENTIFICATION table. If continuity does not exist, inspect and repair circuit as needed.

EGR TEMPERATURE SENSOR TERMINAL IDENTIFICATION

EGR Temperature Sensor Inspection

Remove sensor and immerse in water. Using ohmmeter, check resistance while increasing water temperature. See EGR TEMPERATURE RESISTANCE SPECIFICATIONS table. Replace sensor if resistance measured is not within specification.

EGR TEMPERATURE RESISTANCE SPECIFICATIONS

System Inspection (Elantra & Sonata 4-Cylinder)

Connect timing light and tachometer. Ensure engine is at normal operating temperature. With engine at idle (750 RPM), check ignition timing. See ADJUSTMENTS article for procedure to check and adjust timing.

1. Disconnect ignition coil harness connector. Turn ignition on. Using DVOM, measure voltage between ignition coil harness connector terminal No. 3 (Black/White wire) and vehicle ground. If battery voltage does not exist, inspect and repair circuit as needed.
2. Disconnect power transistor connector. Using ohmmeter, check resistance between ignition coil harness connector terminal No. 1 (Green/White wire on Elantra, White/Black wire on Sonata 4-Cylinder) and power transistor harness connector terminal No. 6. If continuity does not exist, inspect and repair circuit as needed.
3. Using ohmmeter, check resistance between ignition coil harness connector terminal No. 2 (Green/Blue wire on Elantra, White/Red wire on Sonata 4-Cylinder) and power transistor connector terminal No. 1. If continuity does not exist, inspect and repair circuit as needed.
4. Using ohmmeter, check resistance between power transistor harness connector terminal No. 3 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
5. Turn ignition switch to START position. Using DVOM, measure voltage between power transistor harness connector terminal No. 5 (Brown wire on Elantra, Yellow/Black wire on Sonata 4-Cylinder) and vehicle ground. Voltage should be 0.5-4.0 volts. If voltage is within specification, circuit is okay.
6. If voltage is not within specification, turn ignition off. Disconnect ECM harness connector. Using ohmmeter, check resistance between power transistor harness connector terminal No. 5 (Brown wire on Elantra, Yellow/Black wire on Sonata 4-Cylinder) and ECM harness connector terminal No. 5 (18-pin connector) or No. 17 (26-pin connector). (Scheme 8) If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
7. Connect ECM harness connector. Turn ignition switch to START position. Using DVOM, measure voltage between power transistor harness connector terminal No. 2 (White/Black wire on Elantra, Yellow/Blue wire on Sonata 4-Cylinder) and vehicle ground. Voltage should be 0.5-4.0 volts. If voltage is within specification, circuit is okay.
8. If voltage is not within specification, turn ignition off. Disconnect ECM harness connector. Using ohmmeter, check resistance between power transistor harness connector terminal No. 2 (White/Black wire on Elantra, Yellow/Blue wire on Sonata 4-Cylinder) and ECM harness connector terminal No. 6 (18-pin connector) or No. 5 (26-pin connector). (Scheme 8) If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.
9. Connect ECM harness connector. Turn ignition on. Using DVOM, measure voltage between timing adjustment terminal (Light Green/Red) and vehicle ground. Voltage should be 4.0-5.2 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, turn ignition off.
10. Disconnect ECM harness connector. Using ohmmeter, check resistance between ECM harness connector terminal No. 1 (24-pin connector) or No. 5 (16-pin connector) and timing adjustment terminal. (Scheme 8) If continuity does not exist, inspect and repair circuit as needed. If continuity does exist, substitute ECM with known good unit and retest.

Ignition Coil and Power Transistor Inspection

See BASIC TESTING article for specific circuit and component testing.