Engine Controls - Basic Diagnostic Procedures: Other Hyundai Elantra III

Compression

Note. Before checking engine compression pressure ensure engine oil level is correct. Ensure starter motor and battery are operating properly.

Check engine mechanical condition using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer manual for specific instructions. Start engine and allow to operate until coolant temperature is 176-205°F (80-96°C). Check engine compression with engine at specified cranking speed, all spark plugs removed and throttle wide open.

COMPRESSION SPECIFICATIONS

Exhaust System Backpressure

Exhaust system backpressure can be checked with a vacuum or pressure gauge. If using a pressure gauge, remove HO2S sensor. Connect a 1.0-5.0 psi (.07-.35 kg/cm 2 ) pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2.0 psi (.14 kg/cm 2 ), exhaust system or catalytic converter is plugged.

If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, check exhaust system for restrictions.

FUEL SYSTEM

Sonata (2.4L) & XG 300

On Sonata 2.4L and XG 300, disconnect fuel pump harness connector located in trunk. On all models, start engine and allow to idle. After engine stalls, turn ignition off. Disconnect negative battery cable. Reconnect fuel pump harness connector. When repairs are complete and fuel lines are properly secured reconnect negative battery cable. Using fuel pump check connector terminal, activate fuel pump and check for leaks. Repair as necessary. See FUEL PUMP TEST .

Except Sonata (2.4L) & XG 300

Remove rear seat and fuel pump access panel. Disconnect fuel pump harness connector. Start engine and allow to idle. After engine stalls, turn ignition off. Disconnect negative battery cable. Reconnect fuel pump harness connector. When repairs are complete and fuel lines are properly secured, reconnect negative battery cable. Using fuel pump check connector terminal, activate fuel pump and check for leaks. Repair as necessary. See FUEL PUMP TEST .

Accent & Elantra

Note. Fuel pressure regulator is an integral part of fuel pump and is not serviced separately.

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Disconnect high-pressure fuel hose from fuel delivery pipe. Cover hose connection using rags to avoid spraying of fuel.
2. Using Fuel Pressure Gauge Adapter (09353-38000), install fuel pressure gauge to fuel delivery pipe. (Scheme 2) Tighten fuel gauge adapter bolts to 18-26 ft. lbs. (24-35 N.m). Connect negative battery cable.
3. Using fuel pump check connector terminal, activate fuel pump and ensure no fuel leakage is present at pressure gauge or connection. See «FUEL PUMP TEST»(ref-11891-S34743590942000120100000). If no leaks are present, start engine and allow to idle.
4. Measure and record fuel pressure at idle. See «REGULATED FUEL PRESSURE (AT IDLE)»(ref-11891-S24994912742000120100000) table. If measurements are not within specification, go to next step. If fuel pressure is as specified, go to step 7.
5. If fuel pressure is less than specified, check for restricted fuel filter. Check for fuel leak on return side, caused by poor seating of fuel pressure regulator. Replace fuel filter or fuel pump assembly as necessary.
6. If fuel pressure is greater than specified, check for sticking fuel pressure regulator. Check for restricted or bent fuel return hose or pipe. Repair or replace fuel hose, pipe or fuel pump assembly as necessary.
7. If fuel pressures are as specified, stop engine and check gauge for decrease in fuel pressure. Fuel pressure should hold for approximately 5 minutes. If fuel pressure does not hold for approximately 5 minutes go to next step.
8. If fuel pressure decreases slowly after engine is stopped, check for leaking injector. If fuel pressure decreases immediately after engine is stopped, fuel pump check valve is not working. Replace fuel injector or fuel pump as necessary. After repairs are completed, recheck fuel pressure.
9. After testing is completed, release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Disconnect fuel pressure gauge from adapter. Ensure hose connection is covered by shop towel to prevent fuel spray. Remove adapter bolts and adapter, install NEW "O" ring, and reinstall fuel line with original bolts. Apply battery voltage to fuel pump check connector terminal. see scheme 1 Check for fuel leaks.

Scheme 2

Santa Fe, Sonata & XG 300

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Disconnect high-pressure fuel hose from fuel delivery pipe. Cover hose connection using rags to avoid spraying of fuel.
2. Using Fuel Pressure Gauge Adapter (09353-38000), install fuel pressure gauge to fuel delivery pipe. (Scheme 2) Tighten fuel gauge adapter bolts to 18-26 ft. lbs. (24-35 N.m). Connect negative battery cable.
3. Using fuel pump check terminal connector, activate fuel pump and ensure no fuel leakage is present at pressure gauge or connection. See «FUEL PUMP TEST»(ref-11891-S34743590942000120100000). If no leaks are present, start engine and allow to idle.
4. Disconnect vacuum hose from fuel pressure regulator, and plug hose end. Measure and record fuel pressure at idle. Reconnect vacuum hose, and again measure and record fuel pressure. See «REGULATED FUEL PRESSURE (AT IDLE)»(ref-11891-S24994912742000120100000) table. If measurements are not within specification, go to next step. If measurements are okay, go to step 8.
5. If fuel pressure is less than specified, check following conditions: Restricted fuel filter. Fuel pressure regulator leaking fuel to fuel return side. Leaking in-tank fuel pick-up hose. Low fuel pump discharge pressure. Repair or replace as necessary. Recheck fuel pressure.
6. If fuel pressure is greater than specified, check for sticking fuel pressure regulator or a restricted or bent fuel return hose or pipe. Repair or replace fuel hoses or pipe, or replace fuel pressure regulator.
7. If fuel pressure does not change when regulator vacuum hose is connected and disconnected, check for following conditions: Restricted or damaged vacuum hose. Restricted manifold vacuum port. Sticking or poorly seated fuel pressure regulator valve. Repair or replace as necessary. Recheck fuel pressure.
8. If fuel pressures are as specified, stop engine and check for decrease in fuel pressure gauge. Fuel pressure should hold for approximately 5 minutes. If fuel pressure decreases slowly after engine is stopped, check for leaking injector. Replace as necessary. If fuel pressure decreases immediately after engine is stopped, check valve inside fuel pump is not working. Replace fuel pump. After repairs are completed, recheck fuel pressure.
9. After testing is completed, release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Disconnect fuel pressure gauge from adapter. Ensure hose connection is covered by shop towel to prevent fuel spray. Remove adapter bolts and adapter. Install NEW "O" ring, and reinstall fuel line with original bolts. Apply battery voltage to fuel pump drive connector terminal. see scheme 1 Check for fuel leaks.

Tiburon

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Locate fuel filter in left rear corner of engine compartment, below brake master cylinder. Remove quick-tie securing fuel lines together and disconnect master cylinder reservoir connector. Disconnect high-pressure fuel hose from top of fuel filter. Cover hose connection using rags to avoid spraying of fuel.
2. Using Fuel Pressure Gauge Adapter, install fuel pressure gauge to fuel filter. (Scheme 3) Tighten fuel gauge adapter bolt to 18-26 ft. lbs. (24-35 N.m). Connect negative battery cable.
3. Using fuel pump check connector terminal, activate fuel pump and ensure no fuel leakage are present at pressure gauge or connection. See «FUEL PUMP TEST»(ref-11891-S34743590942000120100000). If no leaks are present, start engine and allow to idle.
4. Disconnect vacuum hose from fuel pressure regulator, and plug hose end. Measure and record fuel pressure at idle. Reconnect vacuum hose, and again measure and record fuel pressure. See «REGULATED FUEL PRESSURE (AT IDLE)»(ref-11891-S24994912742000120100000) table. If measurements are not within specification, go to next step. If measurements are okay, go to step 8.
5. If fuel pressure is less than specified, check following conditions: Restricted fuel filter. Fuel pressure regulator leaking fuel to fuel return side. Leaking in-tank fuel pick-up hose. Low fuel pump discharge pressure. Repair or replace as necessary. Recheck fuel pressure.
6. If fuel pressure is greater than specified, check for sticking fuel pressure regulator. Check for a restricted or bent fuel return hose or pipe. Repair or replace fuel hose, pipe or fuel pressure regulator.
7. If fuel pressure does not change when regulator vacuum hose is connected and disconnected, check for following conditions: Restricted or damaged vacuum hose. Restricted manifold vacuum port. Sticking or poorly seated fuel pressure regulator valve. Repair or replace as necessary. Recheck fuel pressure.
8. If fuel pressures are as specified, stop engine and check gauge for a decrease in fuel pressure. Fuel pressure should hold for approximately 5 minutes. If fuel pressure decreases slowly after engine is stopped, check for leaking injector. Replace as necessary. If fuel pressure decreases immediately after engine is stopped, check valve inside fuel pump is not working. Replace fuel pump. After repairs are completed, recheck fuel pressure.
9. After testing is completed, release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11891-S31479904712000120100000). Disconnect fuel pressure gauge from adapter. Ensure hose connection is covered by shop towel to prevent fuel spray. Remove adapter bolts and adapter. Install NEW "O" ring, and reinstall fuel line with original bolts. Apply battery voltage to fuel pump check connector terminal. see scheme 1 Check for fuel leaks.

REGULATED FUEL PRESSURE (AT IDLE)

Scheme 3

Accent & Tiburon

1. Remove ECM control relay located under left side of instrument panel, near fuse panel. Using fused jumper wire, apply battery voltage to relay terminal No. 2. (Scheme 4) Using second fused jumper wire, ground relay terminal No. 4.
2. With relay energized, check for continuity between relay terminals No. 5 and 1 and terminals No. 5 and 3. Continuity should be present until voltage is disconnected. If continuity is as specified, replace relay.

Elantra & Sonata (2.5L)

1. Remove ECM control relay which is mounted to right side of instrument panel center support, under radio. Using fused jumper wire, apply battery voltage to relay terminal No. 4. Using second fused jumper wire, ground relay terminal No. 2. (Scheme 4)
2. With relay energized, check for continuity between relay terminals No. 1 and 5. Continuity should be present until voltage is disconnected. If continuity is not present, replace relay.

Scheme 4

Scheme 5

Santa Fe

1. Remove ECM control relay located under left side of instrument panel, near fuse panel. Using fused jumper wire, apply battery voltage to relay terminal No. 3. (Scheme 4) Using second fused jumper wire, ground relay terminal No. 2.
2. With relay energized, check for continuity between relay terminals No. 1 and 4. Continuity should be present until voltage is disconnected. If continuity is as specified, replace relay.

1. Remove ECM control relay which is mounted to right side of instrument panel center support, under radio. Using fused jumper wire, apply battery voltage to relay terminal No. 8. Using second fused jumper wire, ground relay terminal No. 6. (Scheme 5)
2. With relay energized, check for continuity between relay terminals No. 2 and 3 and terminals No. 2 and 4. Continuity should be present until voltage is disconnected. If continuity is present, go to next step. If continuity is not present, replace relay.
3. Using fused jumper wire, apply battery voltage to relay terminal No. 7. Using second fused jumper wire, ground relay terminal No. 5. With relay energized, check for continuity between relay terminals No. 1 and 7. Continuity should be present until voltage is disconnected. If continuity is not present, replace relay.

IGNITION CHECKS

Note. When troubleshooting components and component control circuits, see WIRING DIAGRAMS article.

Spark (Spark Plug)

Connect spark plug to a high tension cable. Ensure spark plug gap is 0.039-0.043" (1.0-1.1 mm). Ground outer spark plug electrode (main body of spark plug), and crank engine. Spark should occur in discharge gap between electrodes.

Ignition Coil Power Circuit (Accent)

Turn ignition off. Disconnect both ignition coil 2-pin "A" connectors. Turn ignition on. Measure voltage between ground and both "A" connectors terminal No. 1. (Scheme 6) Battery voltage should be present. If battery voltage is not present, repair circuit between coil and ignition switch.

Scheme 6

Ignition Coil Power Circuit (Elantra & Tiburon)

Turn ignition off. Disconnect ignition coil 3-pin connector. Turn ignition on. Measure voltage between connector terminal No. 1 and ground. (Scheme 7) Battery voltage should be present. If battery voltage is not present, repair circuit between coil and ignition switch.

Scheme 7

Ignition Coil Power Circuit (Santa Fe 2.4L & Sonata 2.4L)

1. Turn ignition off. Disconnect suspect coil 3-pin harness connector. Turn ignition on. Measure voltage between ground and coil 3-pin connector terminal No. 1 (Tan/Black wire). (Scheme 8) Battery voltage should be present. If battery voltage is not present, turn ignition off and go to next step.
2. Disconnect ignition failure sensor 4-pin connector. Turn ignition on. Measure voltage between ground and sensor harness connector terminal No. 4 (Pink/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, repair circuit between ignition failure sensor and ignition switch.
3. Check for continuity between ignition failure sensor 4-pin harness connector terminals No. 1 and 2. If continuity is present, repair circuit between ignition failure sensor and suspect coil. If continuity is not present, replace ignition failure sensor.

Scheme 8

Ignition Coil Power Circuit (Santa Fe 2.7L & Sonata 2.5L)

Turn ignition off. Disconnect ignition coil 4-pin connector. Turn ignition on. Measure voltage between ground and harness connector terminal No. 3 (Green wire) on Santa Fe, (Pink/Black wire) on Sonata. (Scheme 9) Battery voltage should be present. If battery voltage is not present, repair circuit between coil and ignition switch.

Scheme 9

Ignition Coil Power Circuit (XG 300)

1. Turn ignition off. Disconnect ignition coil 6-pin connector. (Scheme 10) Turn ignition on. Measure voltage between ground and harness connector terminal No. 1 (Pink/Black wire). Battery voltage should be present. If battery voltage is not present, turn ignition off and go to next step.
2. Disconnect ignition failure sensor 4-pin connector. Turn ignition on. Measure voltage between ground and sensor harness connector terminal No. 4 (Pink/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, repair circuit between ignition failure sensor and ignition switch.
3. Check for continuity between ignition failure sensor harness connector terminals No. 1 and 2. If continuity is present, repair circuit between ignition failure sensor and suspect coil. If continuity is not present, replace ignition failure sensor.

Scheme 10

Ignition Coil Ground Circuit (Accent & Elantra)

Turn ignition off. Disconnect both ignition coil 2-pin "A" connectors. Disconnect ECM 81-pin harness connector. Check for an open or short between ground and both "A" connectors terminal No. 2. Check for an open or short between ground and ECM 81-pin connector terminals No. 2 and No. 5. (Scheme 6)and (Scheme 11). Repair circuits as necessary.

Scheme 11

Ignition Coil Ground Circuit (Santa Fe 2.4L, Sonata 2.4L & XG 300)

Turn ignition off. Check for continuity between ground and suspect coil 3-pin connector terminal No. 2 (Black wire). Continuity should be present. If continuity is not present, repair open between suspect coil and ground connection located on middle of firewall in engine compartment.

Ignition Coil Ground Circuit (Sonata 2.5L)

Turn ignition off. Disconnect ECM 9-pin 94-5 connector and ignition coil 4-pin connector. (Scheme 9)and (Scheme 12). Check for an open or short in ground circuits between specified coil 4-pin harness connector terminals and ECM 94-5 connector terminals. See COIL GROUND CIRCUIT TESTING (SONATA 2.5L) table. Repair circuits as necessary.

Scheme 12

COIL GROUND CIRCUIT TESTING (SONATA 2.5L)

Ignition Coil Ground Circuit (Tiburon)

Turn ignition off. Disconnect ECM 88-pin connector and ignition coil 3-pin connector. (Scheme 7)and (Scheme 13). Check for an open or short between ECM connector terminal No. 25 and coil connector terminal No. 2, and between ECM connector terminal No. 52 and coil connector terminal No. 3. Repair circuits as necessary.

Scheme 13

Ignition Coil Resistance (Accent & Elantra)

1. Turn ignition off. Disconnect both ignition coil 2-pin "A" connectors. Measure primary coil resistance between terminals No. 1 and 2 of each "A" connector. One connector is for cylinders No. 1 and 4, the other is for cylinders No. 2 and 3. (Scheme 6) If resistance is not as specified, replace coil. See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table.
2. To check secondary coil resistance, disconnect spark plug wires. Measure resistance between high-voltage coil terminals No. 1 and 4, and between coil towers No. 2 and 3. (Scheme 7) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

Ignition Coil Resistance (Santa Fe 2.4L & Sonata 2.4L)

1. Turn ignition off. To check primary coil resistance, disconnect suspect coil 3-pin connector. Using a jumper wire, connect coil power transistor terminal No. 2 to power supply ground. Using a fused jumper wire, connect a 3-volt power supply to coil power transistor terminal No. 1. (Scheme 8)
2. Measure resistance between coil power transistor terminals No. 2 and 3. See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. Continuity should only be present when power is connected to terminal No. 1. If resistance is as specified, go to next step. If resistance is not as specified, replace coil.
3. To check secondary coil resistance, disconnect 3-volt power supply and ground from coil power transistor. Measure secondary coil resistance between high voltage terminals No. 1 and 4, and between terminals No. 2 and 3. (Scheme 8) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

Ignition Coil Resistance (Santa Fe 2.7L)

1. Disconnect ignition coil 4-pin connector. Measure primary coil resistance for cylinders No. 1 and 4 between connector terminals No. 2 (Green wire) and 3 (Green wire). Measure primary coil resistance for cylinders No. 2 and 5 between connector terminals No. 1 (Blue/Orange wire) and 3 (Green wire). Measure primary coil resistance for cylinders No. 3 and 6 between coil connector terminals No. 3 (Green wire) and 4 (Brown wire). (Scheme 9) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.
2. To check secondary coil resistance, disconnect spark plug wires. Measure resistance between high-voltage coil terminals No. 1 and 4, between terminals No. 2 and 5, and between terminals No. 3 and 6. (Scheme 9) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

Ignition Coil Resistance (Sonata 2.5L)

1. Disconnect ignition coil 4-pin connector. Measure primary coil resistance for cylinders No. 1 and 4 between connector terminals No. 2 (Yellow/White wire) and 3 (Pink/Black wire). Measure primary coil resistance for cylinders No. 2 and 5 between connector terminals No. 1 (Orange/Black wire) and 3 (Pink/Black wire). Measure primary coil resistance for cylinders No. 3 and 6 between coil connector terminals No. 3 (Pink/Black wire) and 4 (Red/Black wire). (Scheme 9) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.
2. To check secondary coil resistance, disconnect spark plug wires. Measure resistance between high-voltage coil terminals No. 1 and 4, between terminals No. 2 and 5, and between terminals No. 3 and 6. (Scheme 9) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

Ignition Coil Resistance (Tiburon)

1. Disconnect ignition coil 3-pin connector. Measure primary coil resistance for cylinders No. 2 and 3 between coil connector terminals No. 1 and 3. Measure primary coil resistance for cylinders No. 1 and 4 between connector terminals No. 2 and 3. (Scheme 7) If resistance is not as specified, replace coil. See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table.
2. To check secondary coil resistance, disconnect spark plug wires. Measure resistance between high-voltage coil terminals No. 1 and 4, and between high-voltage coil terminals No. 2 and 3. See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

Ignition Coil Resistance (XG 300)

1. Disconnect ignition coil 4-pin connector. Measure primary coil resistance for cylinders No. 1 and 4 between connector terminals No. 1 (Pink/Black wire) and 4 (White wire). Measure primary coil resistance for cylinders No. 2 and 5 between connector terminals No. 1 (Pink/Black wire) and 3 (Orange wire). Measure primary coil resistance for cylinders No. 3 and 6 between coil connector terminals No. 1 (Pink/Black wire) and 2 (Green/White wire). (Scheme 10) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.
2. To check secondary coil resistance, disconnect spark plug wires. Measure resistance between high-voltage coil terminals No. 1 and 4, between terminals No. 2 and 5, and between terminals No. 3 and 6. (Scheme 9) See «DIS IGNITION COIL RESISTANCE»(ref-11891-S42230204002000120100000) table. If resistance is not as specified, replace coil.

DIS IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are as specified.

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no hard codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.