DTC P0300:00 [ZJ, ZY]

id0102c0703200

DTC P0300:00

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 change of interval time exceeds the preprogrammed criteria, the PCM detects 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 the 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).
•  The MIL illuminates if the PCM detects the above malfunction condition 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 misfire which can damage the catalytic converter during first drive cycle.
•  PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
•  FREEZE FRAME DATA is available.
•  The DTC is stored in the PCM memory.
POSSIBLE CAUSE
•  Erratic signal to PCM
―  Brake switch signal malfunction
―  ECT sensor signal malfunction
―  IAT sensor signal malfunction
―  MAF sensor signal malfunction
―  CKP sensor signal malfunction
―  TP sensor signal malfunction
―  VSS signal malfunction
•  CMP sensor malfunction
•  CKP sensor looseness
•  Ignition system malfunction
―  Ignition coil related wiring harness malfunction
―  Ignition coil malfunction
―  Spark plug malfunction
•  MAF sensor contamination
•  Excess air suction in intake air system (between MAF sensor and intake manifold)
―  Vacuum hoses damages or improper connection
―  Pipe malfunction
•  Fuel supply system malfunction or improper fuel line pressure
―  Fuel pump unit malfunction
―  Fuel pressure regulator (built-in fuel pump unit) malfunction
―  Fuel line clogged
―  Fuel filter clogged
―  Fuel leakage in fuel line
―  Fuel runout
•  Improper operation of variable valve timing control system
•  Improper operation of purge solenoid valve
•  Insufficient compression
•  Improper operation of EGR valve
•  Engine coolant leakage
•  PCV valve malfunction
•  Poor quality fuel
•  PCM malfunction

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.
No
Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS 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 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 AND STORED DTC
•  Turn the ignition switch off, then to the ON position (engine off).
•  Verify the related PENDING CODE and stored DTCs using the M-MDS.
•  Are any other DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [ZJ, ZY].)
No
Go to the next step.
4
VERIFY CURRENT INPUT SIGNAL STATUS (IGNITION SWITCH TO ON/IDLE)
•  Perform the PID/DATA Monitor and Record Procedure and access the following PIDs:
―  BOO
―  ECT
―  IAT
―  MAF
―  RPM
―  TP REL
―  VSS
•  Is there any signal that is far out of specification when ignition switch is the ON position and the engine runs at idle?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Go to the next step.
5
VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA CONDITION
•  Perform the PID/DATA Monitor and Record Procedure and access the same PIDs as in Step 4 under the FREEZE FRAME DATA condition.
•  Is there any signal which causes drastic changes?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Go to the next step.
6
INSPECT CMP SENSOR
•  Inspect the CMP sensor.
•  Is there any malfunction?
Yes
Inspect the installation condition and damages on the timing belt and gears.
•  If there is a malfunction:
―  Repair or replace the malfunctioning part.
•  If there is no malfunction:
―  Replace the CMP sensor.
Go to Step 22.
No
Go to the next step.
7
INSPECT INSTALLATION OF CKP SENSOR
•  Inspect if the CKP sensor is loosely installed.
•  Is the CKP sensor installed securely?
Yes
Go to the next step.
No
Retighten the CKP sensor, then go to Step 22.
(See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].)
8
INSPECT IGNITION COIL AND RELATED WIRING HARNESS
•  Inspect the ignition coil and related wiring harness condition (intermittent open or short circuit) for all cylinders.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
(See IGNITION COIL REMOVAL/INSTALLATION [ZJ, ZY].)
No
Go to the next step.
9
INSPECT IGNITION SYSTEM OPERATION
•  Perform the Spark Test.
•  Is the strong blue spark visible at each cylinder?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
10
INSPECT POWER SUPPLY TERMINAL AT IGNITION COIL CONNECTOR
•  Turn the ignition switch off.
•  Disconnect the ignition coil connector.
•  Turn the ignition switch to the ON position (engine off).
•  Measure the voltage between ignition coil terminal A (wiring harness-side) and body ground.
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the wiring harness between ignition coil terminal A and PCM terminal 2A for open circuit.
Repair or replace the wiring harness for a possible open circuit, then go to Step 22.
11
INSPECT IGNITION COIL RESISTANCE
•  Inspect the ignition coil resistance.
•  Is the resistance normal?
Yes
Go to the next step.
No
Replace the ignition coil, then go to Step 22.
(See IGNITION COIL REMOVAL/INSTALLATION [ZJ, ZY].)
12
INSPECT MAF SENSOR
•  Start the engine.
•  Perform the PID/DATA Monitor and Record Procedure and access the MAF PID.
•  Verify that the MAF PID changes quickly according to race the engine RPM.
•  Is the MAF PID response normal?
Yes
Go to the next step.
No
Replace the MAF/IAT sensor, then go to Step 22.
(See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].)
13
INSPECT EXCESSIVE AIR SUCTION IN INTAKE AIR SYSTEM
•  Inspect for air leakage between the following:
―  MAF sensor and throttle body
―  Throttle body and intake manifold
Note
•  Engine speed may change when rust penetrating agent is sprayed on the air suction area.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Go to the next step.
14
INSPECT FUEL LINE PRESSURE
•  Inspect the fuel line pressure.
•  Is the fuel line pressure normal?
Yes
Go to Step 16.
No
If the fuel line pressure is too low:
•  Go to the next step.
If the fuel line pressure is excess high:
•  Replace the fuel pump unit, then go to Step 22.
15
INSPECT FUEL LINE FROM FUEL PUMP TO FUEL DISTRIBUTOR
•  Visually inspect for fuel leakage in fuel line for any leakage.
•  Is there fuel leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Inspect the fuel filter for foreign materials or stain inside fuel filter (low-pressure side).
•  If there is any foreign materials or stain inside fuel filter (low-pressure side):
―  Clean the fuel tank and filter (low-pressure side).
•  If there is no malfunction:
―  Replace the fuel pump unit.
Go to Step 22.
16
INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION
•  Perform the Variable Valve Timing Control System Operation Inspection.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Go to the next step.
17
INSPECT PURGE SOLENOID VALVE OPERATION
•  Turn the ignition switch off.
•  Connect the vacuum pump to the purge solenoid valve and apply vacuum to the purge solenoid valve.
•  Verify that the purge solenoid valve holds vacuum.
•  Turn the ignition switch to the ON position (engine off).
•  Perform the Active Command Modes Procedure and access the EVAPCP PID.
•  Set duty value to 100% for the EVAPCP PID.
•  Apply vacuum while turning the purge solenoid valve from Off to On and simulating EVAPCP PID with 100% duty value.
•  Verify that the purge solenoid valve releases vacuum while the purge solenoid valve is turned ON.
•  Is there any malfunction?
Yes
Replace the purge solenoid valve, then go to Step 22.
(See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [ZJ, ZY].)
No
Go to the next step.
18
INSPECT ENGINE COMPRESSION
•  Inspect the engine compression.
•  Is there any malfunction?
Yes
Perform the engine overhaul for repairs, then go to Step 22.
No
Go to the next step.
19
INSPECT EGR VALVE OPERATION
•  Remove the EGR valve.
•  Visually inspect the EGR valve.
•  Does the EGR valve stuck to open?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
(See EGR VALVE REMOVAL/INSTALLATION [ZJ, ZY].)
No
Go to the next step.
20
INSPECT SEALING OF ENGINE COOLANT PASSAGE
•  Perform the “ENGINE COOLANT LEAKAGE INSPECTION”.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 22.
No
Go to the next step.
21
INSPECT PCV VALVE OPERATION
•  Turn the ignition switch off.
•  Remove the PCV valve and the oil separator as a single unit.
•  Inspect the PCV valve operation.
•  Is there any malfunction?
Yes
Replace the PCV valve, then go to Step 22.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [ZJ, ZY].)
No
Replace the fuel. (Poor quality fuel is used.)
Go to the next step.
22
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the Drive Mode 01 (PCM Adaptive Memory Produce Drive Mode).
•  Is the same PENDING CODE or DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [ZJ, ZY].)
No
Go to the next step.
23
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [ZJ, ZY].)
No
DTC troubleshooting completed.