DTC P0300: Notes

DTC P0300 [AJ] DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0300	Random misfire detected
DETECTION CONDITION	The PCM monitors the CKP sensor input signal interval time. The PCM calculates the change of the interval time for each cylinder. If the change of interval time exceeds the pre programmed criteria, the PCM detects a misfire in the corresponding cylinder, when 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 pre programmed 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 the misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in the PCM. MIL flashes if the PCM detects the misfire which can damage the catalytic converter during first drive cycle. PENDING CODE is available if the PCM detects the misfire which affects emission performance during the first drive cycle. FREEZE FRAME DATA is available. DTC is stored in the PCM memory.
POSSIBLE CAUSE	CMP sensor malfunction CKP sensor malfunction Ignition coil malfunction Ignition system malfunction MAF sensor contamination Excess air suction in intake air system (between MAF/IAT sensor and dynamic chamber) Vacuum hoses damages or improper connection Fuel pump malfunction Fuel pressure regulator malfunction Fuel line clogged Fuel filter clogged Fuel runout Poor quality fuel Fuel leakage in fuel line Insufficient compression Variable valve timing control system improper operation Purge control solenoid valve malfunction PCV valve malfunction EGR valve malfunction Related connector and terminal malfunction Related wiring harness malfunction PCM malfunction

DTC P0300

Random misfire detected

DETECTION CONDITION

The PCM monitors the CKP sensor input signal interval time. The PCM calculates the change of the interval time for each cylinder. If the change of interval time exceeds the pre programmed criteria, the PCM detects a misfire in the corresponding cylinder, when 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 pre programmed 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 the misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in the PCM.
MIL flashes if the PCM detects the misfire which can damage the catalytic converter during first drive cycle.
PENDING CODE is available if the PCM detects the misfire which affects emission performance during the first drive cycle.
FREEZE FRAME DATA is available.
DTC is stored in the PCM memory.

POSSIBLE CAUSE

CMP sensor malfunction
CKP sensor malfunction
Ignition coil malfunction
Ignition system malfunction
MAF sensor contamination
Excess air suction in intake air system (between MAF/IAT sensor and dynamic chamber)
Vacuum hoses damages or improper connection
Fuel pump malfunction
Fuel pressure regulator malfunction
Fuel line clogged
Fuel filter clogged
Fuel runout
Poor quality fuel
Fuel leakage in fuel line
Insufficient compression
Variable valve timing control system improper operation
Purge control solenoid valve malfunction
PCV valve malfunction
EGR valve malfunction
Related connector and terminal malfunction
Related wiring harness malfunction
PCM malfunction