Diagnostic procedure

DTC P0300 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (Misfire related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform the repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		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 ).
3		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 WDS or equivalent. (See PCM INSPECTION ). 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 ). Then go to Step 26.
4		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 ). Then go to Step 26.
5		No	Go to the next step.
6	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION ). Is the CMP sensor normal?	Yes	Go to the next step.
6		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.
7		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.
8		No	Repair the suspected wiring harnesses, then go to Step 26.
9	INSPECT IGNITION SYSTEM OPERATION Carry the out spark test. (See SPARK TEST ) Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
9		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 WDS or equivalent. 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.
10		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.
11		No	Go to the next step.
12	INSPECT FUEL LINE PRESSURE Inspect fuel line pressure. (See FUEL LINE PRESSURE INSPECTION ). Is the fuel line pressure normal?	Yes	Go to Step 14.
12		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.
13		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 ). Is it normal?	Yes	Go to the next step.
14		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 VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION ) Does the variable valve timing control system work properly?	Yes	Go to the next step.
15		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 WDS or equivalent. 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.
16		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 ). Is the PCV valve operation normal?	Yes	Replace the PCV valve, then go to Step 26.
17		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.
18		No	Go to the next step.
19	VERIFY FUEL PUMP SPEED CONTROL OPERATION Perform Fuel Pump Speed Control Inspection. (See FUEL PUMP SPEED CONTROL INSPECTION ). Does the fuel pump speed control work properly?	Yes	Go to the next step.
19		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 USING THE WDS OR EQUIVALENT ).	Yes	Go to Step 24.
20		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.
21		No	Go to Step 23.
22	INSPECT FUEL PRESSURE SENSOR Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION ). Is the fuel pressure sensor normal?	Yes	Go to the next step.
22		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 USING THE WDS OR EQUIVALENT ).	Yes	Go to Step 26.
23		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 ). Is the low side fuel pressure within the specification?	Yes	Go to the next step.
24		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 ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Then go to the next step.
25		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 WDS or equivalent. Perform the HO2S heater, HO2S, and TWC Repair Verification Drive Mode. (See OBD-II DRIVE MODE ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
26		No	Go to the next step.
27	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE ).
27		No	Troubleshooting completed.