Generic Automotive Fault Code
Free · no signupP0300
Flashing Check Engine Light / Engine Shake
System
Ignition
Symptom
Flashing Check Engine Light / Engine Shake
Diagnosis & fix steps
LOGIC: Random / Multiple Cylinder Misfire Detected.
ACTION: Check live data cylinder counters to isolate weak cylinders. Inspect ignition coil boots for carbon tracking, spark plug gaps for wear, and test for unstable fuel pressure.
Red Seal field insights
Critical Safety: A flashing MIL indicates a misfire severe enough to dump raw fuel down the exhaust, which will rapidly overheat and melt the catalytic substrate.
Same code keeps coming back?
That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.
Read before you touch anything
- This is general reference information, not a repair manual. It is for trained, qualified technicians.
- Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
- Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
- You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
- Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.
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