DTC P0300:00 [L5]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSES

DTC P0300:00	Random misfire detected
DETECTION CONDITION	The PCM monitors 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 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 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 the misfire which affects emission performance during first drive cycle FREEZE FRAME DATA is available The DTC is stored in the PCM memory
POSSIBLE CAUSE	Erratic signal to PCM APP sensor 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 connector or terminal malfunction CMP sensor malfunction CKP sensor connector or terminal malfunction CKP sensor malfunction Ignition system malfunction Spark plug malfunction Ignition coil related wiring harness malfunction Ignition coil malfunction MAF sensor malfunction Excessive air suction in intake air system (between MAF sensor and intake manifold) Vacuum hose damaged Pipe malfunction Fuel supply system or low fuel line pressure malfunction Fuel leakage in fuel line Clogged or restricted fuel filter Fuel pressure regulator (built-in fuel pump unit) malfunction Fuel runout Fuel pump unit malfunction Purge solenoid valve malfunction Variable valve timing control system improper operation EGR valve malfunction PCV valve malfunction Engine malfunction Engine coolant leakage Insufficient compression Poor quality fuel PCM malfunction

DTC P0300:00

Random misfire detected

DETECTION CONDITION

The PCM monitors 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 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 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 the misfire which affects emission performance during first drive cycle
FREEZE FRAME DATA is available
The DTC is stored in the PCM memory

POSSIBLE CAUSE

Erratic signal to PCM
- APP sensor 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 connector or terminal malfunction
CMP sensor malfunction
CKP sensor connector or terminal malfunction
CKP sensor malfunction
Ignition system malfunction
- Spark plug malfunction
- Ignition coil related wiring harness malfunction
- Ignition coil malfunction
MAF sensor malfunction
Excessive air suction in intake air system (between MAF sensor and intake manifold)
- Vacuum hose damaged
- Pipe malfunction
Fuel supply system or low fuel line pressure malfunction
- Fuel leakage in fuel line
- Clogged or restricted fuel filter
- Fuel pressure regulator (built-in fuel pump unit) malfunction
- Fuel runout
- Fuel pump unit malfunction
Purge solenoid valve malfunction
Variable valve timing control system improper operation
EGR valve malfunction
PCV valve malfunction
Engine malfunction
- Engine coolant leakage
- Insufficient compression
- Poor quality fuel
PCM malfunction