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2000 Honda CRV B20B Misfire Diagnosis: P0300-P0303 & P0420/P1399 Codes Explained

Model: Honda B20B CRV Fault Code: P0300 Posted: 2007-12-22 02:18

I own a 2000 Honda CRV with the 2.0L B20B engine. The check engine light is on, and diagnostic scans have revealed six fault codes: P0300, P0301, P0302, P0303, P0420, and P1399. I'm not an expert in modern car computer systems, but I've worked on many vehicles before—so I’m not a beginner. Can someone help me understand what these codes mean? Specifically, which sensors or components are most likely causing the misfires? The presence of multiple cylinder misfire codes (P0301–P0303) suggests an issue with ignition system components or fuel delivery. P0420 indicates the catalytic converter is not performing efficiently, and P1399 points to a possible ignition-related problem. I'm looking for clear, technical explanations that help identify likely root causes—especially regarding spark plugs, coils, wiring, or sensor failures.

Related fault codes
P0300
Comments (2)
Anonymous 2007-12-22 11:12

The codes you're seeing mean: - P0300: Random/Multiple Cylinder Misfire - P0301: Misfire in Cylinder 1 - P0302: Misfire in Cylinder 2 - P0303: Misfire in Cylinder 3 - P0420: Catalytic Converter Efficiency Below Threshold - P1399: Ignition System or Misfire Detected Key troubleshooting steps: - Inspect the spark plug coil for Cylinder #4 (the one not showing a misfire)—a failing coil can cause intermittent issues. - Check all wiring and electrical connections, especially to the crankshaft position sensor. - If misfiring has persisted over time, consider replacing the catalytic converter due to potential degradation. These codes are common in 2000 Honda CRV B20B engines. Addressing ignition components first is usually effective. Good luck—please update if you find a resolution.

Anonymous 2014-01-09 16:04

I recently had the same issue on my 2001 Honda CRV with P0301–P0304 (all cylinders misfiring) and P1456 (EVAP System Leak Detected – Fuel Tank). I didn’t have a P0420, which suggests my catalytic converter is still functional. The EVAP leak led me to suspect the gas cap, but it appears in good condition. I’ve tightened it multiple times and even added foam to ensure a tight seal—still no improvement. Smog test results show low emissions readings, yet the vehicle fails due to OBD-II alerts. This makes me question whether significant misfires are actually occurring. I have limited experience with gas caps causing engine misfires, but given the complexity of modern sensors and controls, it’s not impossible. I’ve been unemployed for some time and can’t afford a shop visit for diagnosis—so I’m trying to troubleshoot myself. I suspect the distributor might be faulty, though I'm unsure how to test it properly. Any insights from someone who has resolved this issue would be very helpful. Thanks, Dave