Ground Circuits
- Turn ignition off. Using a DVOM, check continuity between chassis ground and ECM ground terminals. See GROUND TERMINAL IDENTIFICATION table. DVOM should indicate zero ohms. If resistance is not as specified, check and repair circuit between ECM and ground.
- Connect voltmeter negative lead to chassis ground. Connect positive lead to each ECM ground terminal. See ECM 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 ECM POWER TERMINAL IDENTIFICATION table. If battery voltage is not present, check operation of SFI control relay. See RELAYS.
| Application | (1) ECM Terminals No. |
|---|---|
| Sonata | 1 & 14 |
| (1) (Scheme 1) | |
| (1) | (Scheme 1) |
ECM GROUND TERMINAL IDENTIFICATION
| Application | (1) ECM Terminals No. |
|---|---|
| Sonata | |
| 2.0L | 2, 15 & 22 |
| (1) (Scheme 1) | |
| (1) | (Scheme 1) |
ECM POWER TERMINAL IDENTIFICATION
Scheme 1
A/C SWITCH CIRCUITS
Disconnect ECM harness connector. Turn ignition and A/C switches to ON position. Using a DVOM, check voltage to A/C switch at ECM connector terminals. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage is present, circuit is okay. If battery voltage is not present, repair affected circuit and retest.
ACCELERATION/ROUGH ROAD SENSOR
See related DTC in appropriate TESTS W/CODES article.
BAROMETRIC (BARO) PRESSURE SENSOR
See related DTC in appropriate TESTS W/CODES article.
CAMSHAFT POSITION (CMP) SENSOR
See related DTC in appropriate TESTS W/CODES article.
CRANKSHAFT POSITION (CKP) SENSOR
See related DTC in appropriate TESTS W/CODES article.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
See related DTC in appropriate TESTS W/CODES article.
HEATED OXYGEN SENSOR (HO2S)
See related DTC in appropriate TESTS W/CODES article.
INTAKE AIR TEMPERATURE (IAT) SENSOR
See related DTC in appropriate TESTS W/CODES article.
IDLE SPEED CONTROL (ISC) ACTUATOR
See related DTC in appropriate TESTS W/CODES article.
KNOCK SENSOR (KS)
See related DTC in appropriate TESTS W/CODES article.
MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR
See related DTC in appropriate TESTS W/CODES article.
MASS AIRFLOW (MAF) SENSOR
See related DTC in appropriate TESTS W/CODES article.
POWER STEERING PRESSURE SWITCH
- 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 be present with wheels in straight-ahead position and engine idling. Continuity should be present when wheels are turned.
- Turn engine off. Turn ignition switch to ON position. Connect DVOM between switch connector and chassis ground. Battery voltage should be present. If battery voltage is present, circuit is okay. If battery voltage is not present, check and repair circuit between switch connector and ECM.
THROTTLE POSITION (TP) SENSOR
See related DTC in appropriate TESTS W/CODES article.
TRANSAXLE RANGE (TR) SWITCH (A/T MODELS)
- TR switch is mounted to transaxle, near shift lever mechanism. Ensure switch is adjusted properly. Switch output can be affected by improper adjustment. Check power supply voltage to switch. Disconnect ECM and TR switch harness connectors. Turn ignition switch to START position.
- Check voltage between vehicle ground and TR switch harness connector terminal No. 11. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-16646) article. Battery voltage should be present. If battery voltage is not present, inspect and repair power supply circuit.
- Turn ignition off. Disconnect ECM harness connector. Turn ignition switch to START position. Check TR switch input voltage. Voltage reading should be 8 volts or greater. If voltage reading is as specified, check control cable adjustment or for faulty TR switch. Repair or replace as necessary. If voltage reading is not as specified, check input supply voltage circuit.
VEHICLE SPEED SENSOR (VSS)
See related DTC in appropriate TESTS W/CODES article.
RELAYS
Note. SFI control relay may also be referred to as the ECM main relay.
| CAUTION | When applying direct battery voltage, ensure voltage is applied to correct terminal; otherwise, relay damage could result. |
SFI CONTROL RELAY
- Relay is located behind right kick panel, near ECM. Disconnect relay harness connector and remove relay from holder. Apply battery voltage to relay terminal No. 6 (positive) and ground terminal No. 8 (negative). (Scheme 2)
- Using a DVOM, check for continuity between relay terminals No. 1 and 8. Continuity should be present. Check for continuity between relay terminals No. 3 and 4. Continuity should be present. If continuity is present in both checks go to next step. If continuity is not present on both checks, replace relay.
- Apply battery voltage to relay terminal No. 3 (positive) and ground terminal No. 9 (negative). Using DVOM, check voltage between relay terminal No. 4 and ground. Battery voltage should be present. Disconnect battery voltage to relay. DVOM should read zero volts. If voltage readings are not as specified, replace relay. If voltage readings are specified, go to next step.
- Turn ignition off. Using DVOM connected to ground, backprobe ECM terminal No. 22. (Scheme 1) Turn ignition on. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check circuit between terminal No. 22 and ignition switch. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-16646) article.
- Connect DVOM between SFI relay harness connector terminal No. 6 and ground. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check circuit between relay an ignition switch.
- Turn ignition off. Disconnect ECM harness connector. Connect DVOM between ECM terminal No. 1 and relay harness connector terminal No. 8. Check for open or short to ground in circuit between ECM and relay. Repair circuit as necessary. If circuit is okay, go to next step.
- Connect DVOM between relay harness connector terminal No. 1 and ECM terminal No. 2, then to ECM terminal No. 15. Check for open or short in circuit between ECM and relay. Repair circuit as necessary.
Scheme 2
POWER TRANSISTOR
See BASIC TESTING article.
FUEL DELIVERY
Note. For fuel system pressure testing, see BASIC TESTING article.
Fuel Pump
See related DTC in appropriate TESTS W/CODES article.
Fuel Injectors
See related DTC in appropriate TESTS W/CODES article.
IDLE CONTROL SYSTEM
Note. For Idle Speed Control (ISC) actuator testing information, see related DTC in appropriate TESTS W/CODES article.
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.
FUEL EVAPORATION
Note. For further EVAP system testing, see related DTC in appropriate TESTS W/CODES article.
Purge Control Solenoid Valve
- Disconnect vacuum hose and harness connector from purge control solenoid valve. Connect vacuum pump purge control solenoid. Apply vacuum and battery voltage and ground to solenoid. With battery voltage applied, vacuum should release. With battery voltage disconnected, vacuum should hold.
- 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.