SYS.OK|MANUAL.DBâ—Ź LIVE
HOMESERVICE MANUALSMAZDA20066 S, 4D SEDAN, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM AJ]DTC P0300NOTES
2006 Mazda 6 s, 4D Sedan, Standard

DTC P0300: Notes

2006 Mazda 6 s, 4D Sedan, StandardSECTION 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
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.