DTC P0300 [L3 Turbo]

DTC P0300	Random misfire detected
DETECTION CONDITION	• The PCM monitors the CKP sensor input signal interval time. The PCM calculates the change of interval time for each cylinder. If the change of interval time exceeds the preprogrammed criteria, the PCM detects a misfire in the corresponding cylinder. While the engine is running, the PCM counts the number of misfires that occurred at 200 crankshaft revolutions and 1,000 crankshaft revolutions and calculates a misfire ratio for each crankshaft revolution. If the ratio exceeds the preprogrammed criteria, the PCM determines that a misfire, which can damage the catalytic converter or affect emission performance, has occurred. Diagnostic support note • This is a continuous monitor (Misfire). • MIL illuminates if the PCM detects a misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • The MIL flashes if the PCM detects a misfire which can damage the catalytic converter during the first drive cycle. • PENDING CODE is available if the PCM detects a misfire which affects emission performance during the first drive cycle. • FREEZE FRAME DATA is available. • DTC is stored in the PCM memory.
POSSIBLE CAUSE	• CKP sensor malfunction • CMP sensor malfunction • Ignition coil malfunction • Ignition system malfunction • MAF sensor contamination • Excess air suction in intake air system (between MAF sensor and intake manifold) • Fuel pump malfunction • High pressure fuel pump malfunction • Relief valve (built-in fuel delivery pipe) malfunction • Spill valve control solenoid valve (built-in high pressure fuel pump) malfunction • Improper fuel pump speed control operation • Fuel pressure regulator (built-in fuel pump unit) malfunction • Fuel line clogged • Fuel filter clogged • Fuel leakage in fuel line • Fuel runout • Poor quality fuel • Purge control solenoid valve malfunction • PCV valve malfunction • EGR valve malfunction • Vacuum hoses damage or improper connection • Related connector and terminal malfunction • Related wiring harness malfunction • Insufficient compression • Variable valve timing control system improper

DTC P0300

Random misfire detected

DETECTION CONDITION

• The PCM monitors the CKP sensor input signal interval time. The PCM calculates the change of interval time for each cylinder. If the change of interval time exceeds the preprogrammed criteria, the PCM detects a misfire in the corresponding cylinder. While the engine is running, the PCM counts the number of misfires that occurred at 200 crankshaft revolutions and 1,000 crankshaft revolutions and calculates a misfire ratio for each crankshaft revolution. If the ratio exceeds the preprogrammed criteria, the PCM determines that a misfire, which can damage the catalytic converter or affect emission performance, has occurred.

Diagnostic support note

• This is a continuous monitor (Misfire).

• MIL illuminates if the PCM detects a misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

• The MIL flashes if the PCM detects a misfire which can damage the catalytic converter during the first drive cycle.

• PENDING CODE is available if the PCM detects a misfire which affects emission performance during the first drive cycle.

• FREEZE FRAME DATA is available.

• DTC is stored in the PCM memory.

POSSIBLE CAUSE

• CKP sensor malfunction

• CMP sensor malfunction

• Ignition coil malfunction

• Ignition system malfunction

• MAF sensor contamination

• Excess air suction in intake air system (between MAF sensor and intake manifold)

• Fuel pump malfunction

• High pressure fuel pump malfunction

• Relief valve (built-in fuel delivery pipe) malfunction

• Spill valve control solenoid valve (built-in high pressure fuel pump) malfunction

• Improper fuel pump speed control operation

• Fuel pressure regulator (built-in fuel pump unit) malfunction

• Fuel line clogged

• Fuel filter clogged

• Fuel leakage in fuel line

• Fuel runout

• Poor quality fuel

• Purge control solenoid valve malfunction

• PCV valve malfunction

• EGR valve malfunction

• Vacuum hoses damage or improper connection

• Related connector and terminal malfunction

• Related wiring harness malfunction

• Insufficient compression

• Variable valve timing control system improper

STEP	INSPECTION	ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform the repair or diagnosis according to the available Service Information. • If the vehicle is not repaired, go to the next step.
No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTC • Turn the ignition switch off then to the ON position (Engine off). • Verify related pending code or stored DTCs. • Are other DTCs present?	Yes	Go to the appropriate DTC troubleshooting. (See DTC TABLE [L3 Turbo].)
No	Go to the next step.
4	VERIFY CURRENT INPUT SIGNAL STATUS (KEY TO ON/IDLE) • Access APP1, APP2, ECT, IAT, MAF, RPM, TP, and VSS PIDs using the M-MDS. (See PCM INSPECTION [L3 Turbo].) • Is there any signal that is far out of specification when the ignition switch is turned to the ON position and the engine idles?	Yes	Inspect the suspected circuit and/or part according to the inspection results. (See PCM INSPECTION [L3 Turbo].) Then go to Step 26.
No	Go to the next step.
5	VERIFY CURRENT INPUT SIGNAL STATUS UNDER TROUBLE CONDITION • Inspect the same PIDs as in Step 4 while simulating FREEZE FRAME DATA condition. • Is there any signal which causes drastic changes?	Yes	Inspect the suspected circuit and/or part according to the inspection results. (See PCM INSPECTION [L3 Turbo].) Then go to Step 26.
No	Go to the next step.
6	INSPECT CMP SENSOR • Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L3 Turbo].) • Is the CMP sensor normal?	Yes	Go to the next step.
No	Inspect the installation condition for damage to the timing chain and gears, repair the malfunctioning part. • If it is normal, replace the CMP sensor. Then go to Step 26.
7	VERIFY CKP SENSOR INSTALLATION CONDITION • Inspect the CKP sensor for looseness. • Is the CKP sensor loose?	Yes	Retighten the CKP sensor, then go to Step.
No	Go to the next step.
8	INSPECT IGNITION COIL HARNESSES • Inspect the ignition coil related wiring harness condition (intermittent open or short) for all cylinders. • Are wiring harness conditions normal?	Yes	Go to the next step.
No	Repair the suspected wiring harnesses, then go to Step 26.
9	INSPECT IGNITION SYSTEM OPERATION • Carry the out spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) • Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the spark test result. Then go to Step 26.
10	INSPECT MAF PID • Start the engine. • Access the MAF PID using the M-MDS. • Race the engine and verify that the MAF PID changes quickly according to the change in the engine speed. • Is the MAF PID response normal?	Yes	Go to the next step.
No	Replace the MAF sensor, then go to Step 26.
11	INSPECT IN INTAKE AIR SYSTEM FOR EXCESSIVE AIR SUCTION • Inspect for air leakage at the following: ― Between the MAF sensor and throttle body ― Between throttle body and intake manifold • Is there any malfunction?	Yes	Repair or replace suspected part, then go to Step 26.
No	Go to the next step.
12	INSPECT FUEL LINE PRESSURE • Inspect fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [L3 Turbo].) • Is the fuel line pressure normal?	Yes	Go to Step 14.
No	If the fuel line pressure is too low, go to the next step. If the fuel line pressure is too high, replace the fuel pump unit, then go to Step 26.
13	INSPECT FUEL LINE FROM FUEL PUMP TO FUEL DELIVERY PIPE • Visually inspect fuel line for fuel leakage. • Is there any fuel leakage?	Yes	Replace suspected fuel line, then go to Step 20.
No	Inspect the fuel filters for following: • Foreign material or stain inside fuel filter (low-pressure side) Perform following actions depend on the result above. • If foreign materials or stain is found inside fuel filter (low-pressure side), clean the fuel tank and filter (low-pressure side). • If normal, replace the fuel pump unit. Then, go to Step 26.
14	INSPECT ENGINE COMPRESSION • Inspect the engine compression. (See COMPRESSION INSPECTION [L3 Turbo].) • Is it normal?	Yes	Go to the next step.
No	Perform engine overhaul for repairs, then go to Step 26.
15	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION • Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) • Does the variable valve timing control system work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the variable valve timing control system inspection results, then go to Step 26.
16	INSPECT OPERATION OF PURGE CONTROL SOLENOID VALVE • Turn the ignition switch off. • Connect the vacuum pump to the purge control solenoid valve and apply vacuum to the solenoid. • Verify that the solenoid holds vacuum. • Turn the ignition switch to the ON position (Engine off). • Access EVAPCP PID in the SIMULATION TEST using the M-MDS. • Set duty value to 100% for the EVAPCP PID. • Apply vacuum while turning the solenoid from OFF to ON and simulating the EVAPCP PID with a 100% duty value. • Verify that the solenoid releases vacuum while the solenoid is turned on. • Is the purge control solenoid valve operation normal?	Yes	Go to the next step.
No	Replace the purge control solenoid valve, then go to Step 26.
17	INSPECT PCV VALVE OPERATION • Turn the ignition switch off. • Remove the PCV valve and inspect the valve operation. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [L3 Turbo].) • Is the PCV valve operation normal?	Yes	Replace the PCV valve, then go to Step 26.
No	Go to the next step.
18	INSPECT OPERATION OF EGR VALVE • Remove the EGR valve. • Visually inspect the if EGR valve is stuck open. • Is the EGR valve stuck open?	Yes	Repair or replace the EGR valve, then go to Step 26.
No	Go to the next step.
19	VERIFY FUEL PUMP SPEED CONTROL OPERATION • Perform Fuel Pump Speed Control Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) • Does the fuel pump speed control work properly?	Yes	Go to the next step.
No	Inspect or replace the malfunctioning parts, according to inspection results. Then go to Step 26.
20	INSPECT FUEL PRESSURE (HIGH-SIDE) • Access and monitor the FUEL_PRES PID. • Is the FUEL_PRES PID value within the specification? (See PCM INSPECTION [L3 Turbo].)	Yes	Go to Step 24.
No	Go to the next step.
21	IDENTIFY CAUSE BY FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP • Is the vehicle accelerate performance normally?	Yes	Go to the next step.
No	Go to Step 23.
22	INSPECT FUEL PRESSURE SENSOR • Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [L3 Turbo].) • Is the fuel pressure sensor normal?	Yes	Go to the next step.
No	Replace the fuel delivery pipe, then go to Step 26.
23	INSPECT HIGH PRESSURE FUEL PUMP • Replace the high pressure fuel pump • Monitor FUEL_PRES PID • Is the FUEL_PRES PID value within the specified? (See PCM INSPECTION [L3 Turbo].)	Yes	Go to Step 26.
No	Go to the next step.
24	INSPECT FUEL PRESSURE (LOW-SIDE) • Connect the fuel pressure gauge between the fuel pump and the high pressure fuel pump. • Measure the low side fuel pressure. (See FUEL LINE PRESSURE INSPECTION [L3 Turbo].) • Is the low side fuel pressure within the specification?	Yes	Go to the next step.
No	Inspect for the following. • Fuel line restriction • Fuel filter clogging If normal replace the fuel pump.Then go to Step 26.
25	INSPECT SEALING OF ENGINE COOLANT PASSAGE • Perform “ENGINE COOLANT LEAKAGE INSPECTION.” (See ENGINE COOLANT LEAKAGE INSPECTION [L3 Turbo].) • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Then go to the next step.
No	Go to the next step.
26	VERIFY TROUBLESHOOTING OF MISFIRE DTC COMPLETED • Make sure to reconnect all disconnected connectors. • Turn the ignition switch to the ON position (Engine off). • Clear the DTC from the memory using the M-MDS. • Perform the KOER self-test using the M-MDS. • Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3 Turbo].)
No	Go to the next step.
27	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [L3 Turbo].) • Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE [L3 Turbo].)
No	Troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

Record the FREEZE FRAME DATA on the repair order, then go to the next step.

VERIFY RELATED SERVICE INFORMATION AVAILABILITY

• Verify related Service Information availability.

• Is any related Service Information available?

Yes

Perform the repair or diagnosis according to the available Service Information.

• If the vehicle is not repaired, go to the next step.

Go to the next step.

VERIFY RELATED PENDING CODE OR STORED DTC

• Turn the ignition switch off then to the ON position (Engine off).

• Verify related pending code or stored DTCs.

• Are other DTCs present?

Yes

Go to the appropriate DTC troubleshooting.

(See DTC TABLE [L3 Turbo].)

Go to the next step.

VERIFY CURRENT INPUT SIGNAL STATUS (KEY TO ON/IDLE)

• Access APP1, APP2, ECT, IAT, MAF, RPM, TP, and VSS PIDs using the M-MDS.

(See PCM INSPECTION [L3 Turbo].)

• Is there any signal that is far out of specification when the ignition switch is turned to the ON position and the engine idles?

Yes

Inspect the suspected circuit and/or part according to the inspection results.

(See PCM INSPECTION [L3 Turbo].)

Then go to Step 26.

Go to the next step.

VERIFY CURRENT INPUT SIGNAL STATUS UNDER TROUBLE CONDITION

• Inspect the same PIDs as in Step 4 while simulating FREEZE FRAME DATA condition.

• Is there any signal which causes drastic changes?

Yes

Inspect the suspected circuit and/or part according to the inspection results.

(See PCM INSPECTION [L3 Turbo].)

Then go to Step 26.

Go to the next step.

INSPECT CMP SENSOR

• Inspect the CMP sensor.

(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L3 Turbo].)

• Is the CMP sensor normal?

Yes

Go to the next step.

Inspect the installation condition for damage to the timing chain and gears, repair the malfunctioning part.

• If it is normal, replace the CMP sensor.

Then go to Step 26.

VERIFY CKP SENSOR INSTALLATION CONDITION

• Inspect the CKP sensor for looseness.

• Is the CKP sensor loose?

Yes

Retighten the CKP sensor, then go to Step.

Go to the next step.

INSPECT IGNITION COIL HARNESSES

• Inspect the ignition coil related wiring harness condition (intermittent open or short) for all cylinders.

• Are wiring harness conditions normal?

Yes

Go to the next step.

Repair the suspected wiring harnesses, then go to Step 26.

INSPECT IGNITION SYSTEM OPERATION

• Carry the out spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

• Is a strong blue spark visible at each cylinder?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the spark test result.

Then go to Step 26.

INSPECT MAF PID

• Start the engine.

• Access the MAF PID using the M-MDS.

• Race the engine and verify that the MAF PID changes quickly according to the change in the engine speed.

• Is the MAF PID response normal?

Yes

Go to the next step.

Replace the MAF sensor, then go to Step 26.

INSPECT IN INTAKE AIR SYSTEM FOR EXCESSIVE AIR SUCTION

• Inspect for air leakage at the following:

― Between the MAF sensor and throttle body

― Between throttle body and intake manifold

• Is there any malfunction?

Yes

Repair or replace suspected part, then go to Step 26.

Go to the next step.

INSPECT FUEL LINE PRESSURE

• Inspect fuel line pressure.

(See FUEL LINE PRESSURE INSPECTION [L3 Turbo].)

• Is the fuel line pressure normal?

Yes

Go to Step 14.

If the fuel line pressure is too low, go to the next step.

If the fuel line pressure is too high, replace the fuel pump unit,

then go to Step 26.

INSPECT FUEL LINE FROM FUEL PUMP TO FUEL DELIVERY PIPE

• Visually inspect fuel line for fuel leakage.

• Is there any fuel leakage?

Yes

Replace suspected fuel line, then go to Step 20.

Inspect the fuel filters for following:

• Foreign material or stain inside fuel filter (low-pressure side)

Perform following actions depend on the result above.

• If foreign materials or stain is found inside fuel filter (low-pressure side), clean the fuel tank and filter (low-pressure side).

• If normal, replace the fuel pump unit.

Then, go to Step 26.

INSPECT ENGINE COMPRESSION

• Inspect the engine compression.

(See COMPRESSION INSPECTION [L3 Turbo].)

• Is it normal?

Yes

Go to the next step.

Perform engine overhaul for repairs, then go to Step 26.

INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION

• Inspect variable valve timing control system operation.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

• Does the variable valve timing control system work properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the variable valve timing control system inspection results, then go to Step 26.

INSPECT OPERATION OF PURGE CONTROL SOLENOID VALVE

• Turn the ignition switch off.

• Connect the vacuum pump to the purge control solenoid valve and apply vacuum to the solenoid.

• Verify that the solenoid holds vacuum.

• Turn the ignition switch to the ON position (Engine off).

• Access EVAPCP PID in the SIMULATION TEST using the M-MDS.

• Set duty value to 100% for the EVAPCP PID.

• Apply vacuum while turning the solenoid from OFF to ON and simulating the EVAPCP PID with a 100% duty value.

• Verify that the solenoid releases vacuum while the solenoid is turned on.

• Is the purge control solenoid valve operation normal?

Yes

Go to the next step.

Replace the purge control solenoid valve, then go to Step 26.

INSPECT PCV VALVE OPERATION

• Turn the ignition switch off.

• Remove the PCV valve and inspect the valve operation.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [L3 Turbo].)

• Is the PCV valve operation normal?

Yes

Replace the PCV valve, then go to Step 26.

Go to the next step.

INSPECT OPERATION OF EGR VALVE

• Remove the EGR valve.

• Visually inspect the if EGR valve is stuck open.

• Is the EGR valve stuck open?

Yes

Repair or replace the EGR valve, then go to Step 26.

Go to the next step.

VERIFY FUEL PUMP SPEED CONTROL OPERATION

• Perform Fuel Pump Speed Control Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

• Does the fuel pump speed control work properly?

Yes

Go to the next step.

Inspect or replace the malfunctioning parts, according to inspection results.

Then go to Step 26.

INSPECT FUEL PRESSURE (HIGH-SIDE)

• Access and monitor the FUEL_PRES PID.

• Is the FUEL_PRES PID value within the specification?

(See PCM INSPECTION [L3 Turbo].)

Yes

Go to Step 24.

Go to the next step.

IDENTIFY CAUSE BY FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP

• Is the vehicle accelerate performance normally?

Yes

Go to the next step.

Go to Step 23.

INSPECT FUEL PRESSURE SENSOR

• Inspect the fuel pressure sensor.

(See FUEL PRESSURE SENSOR INSPECTION [L3 Turbo].)

• Is the fuel pressure sensor normal?

Yes

Go to the next step.

Replace the fuel delivery pipe, then go to Step 26.

INSPECT HIGH PRESSURE FUEL PUMP

• Replace the high pressure fuel pump

• Monitor FUEL_PRES PID

• Is the FUEL_PRES PID value within the specified?

(See PCM INSPECTION [L3 Turbo].)

Yes

Go to Step 26.

Go to the next step.

INSPECT FUEL PRESSURE (LOW-SIDE)

• Connect the fuel pressure gauge between the fuel pump and the high pressure fuel pump.

• Measure the low side fuel pressure.

(See FUEL LINE PRESSURE INSPECTION [L3 Turbo].)

• Is the low side fuel pressure within the specification?

Yes

Go to the next step.

Inspect for the following.

• Fuel line restriction

• Fuel filter clogging

If normal replace the fuel pump.Then go to Step 26.

INSPECT SEALING OF ENGINE COOLANT PASSAGE

• Perform “ENGINE COOLANT LEAKAGE INSPECTION.”

(See ENGINE COOLANT LEAKAGE INSPECTION [L3 Turbo].)

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Then go to the next step.

Go to the next step.

VERIFY TROUBLESHOOTING OF MISFIRE DTC COMPLETED

• Make sure to reconnect all disconnected connectors.

• Turn the ignition switch to the ON position (Engine off).

• Clear the DTC from the memory using the M-MDS.

• Perform the KOER self-test using the M-MDS.

• Is the PENDING CODE for this DTC present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [L3 Turbo].)

Go to the next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform the “AFTER REPAIR PROCEDURE”.

(See AFTER REPAIR PROCEDURE [L3 Turbo].)

• Are any DTCs present?

Yes

Go to the applicable DTC troubleshooting.

(See DTC TABLE [L3 Turbo].)

Troubleshooting completed.