DTC P0300: Notes

DETECTION CONDITION AND POSSIBLE CAUSE (DTC P0300)

DTC P0300	Random misfire detected
DETECTION CONDITION	The PCM monitors CKP sensor input signal interval time. The PCM calculates change of interval time for each cylinder. If change of interval time exceeds preprogrammed criteria, the PCM detects misfire in the corresponding cylinder. While the engine is running, the PCM counts number of misfires that occurred at 200 crankshaft revolutions and 1,000 crankshaft revolutions and calculates misfire ratio for each crankshaft revolution. If the ratio exceeds the preprogrammed criteria, the PCM determines that a misfire, which can damage 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 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 the misfire which can damage the catalytic converter during the 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. The 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 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 damages 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 CKP sensor input signal interval time. The PCM calculates change of interval time for each cylinder. If change of interval time exceeds preprogrammed criteria, the PCM detects misfire in the corresponding cylinder. While the engine is running, the PCM counts number of misfires that occurred at 200 crankshaft revolutions and 1,000 crankshaft revolutions and calculates misfire ratio for each crankshaft revolution. If the ratio exceeds the preprogrammed criteria, the PCM determines that a misfire, which can damage 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 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 the misfire which can damage the catalytic converter during the 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.
The 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
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 damages or improper connection
Related connector and terminal malfunction
Related wiring harness malfunction
Insufficient compression
Variable valve timing control system improper