P0301 means the PCM counted excessive misfire on cylinder 1; it does not name a coil. Confirm cylinder numbering from the exact B20, K24, L15 turbo or hybrid engine diagram. Save cold/load counters, keep plugs in order and make one controlled coil swap. If the count stays on cylinder 1, test injector command/delivery and compression/leak-down. Cold-start injector leakage, tight valve clearance, a cracked plug or direct-injection pressure problem can all look like a coil fault. Honda has no one P0301 bulletin that supplies the same repair for every CR-V generation.
Match the symptom
Select the closest observation. The result changes the first test; it does not name a part to replace.
Stop sustained driving to protect the catalyst.
What can set P0301—and how to separate it
The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.
| Possible cause | Evidence that supports it | First useful test |
|---|---|---|
| Cylinder 1 plug fouled/worn/cracked | Abnormal deposit, gap or insulation | Labelled plug comparison |
| Coil/boot/connector fault | Misfire follows controlled swap or circuit fails | One swap and loaded circuit test |
| Injector leak/restriction/circuit | Count stays; contribution/delivery differs | Injector balance/leak/command tests |
| Valve-clearance or compression fault | Low relative/measured compression | Compression and leak-down |
| Air leak near cylinder 1 runner | Idle trim/misfire and localized smoke evidence | Intake smoke test |
One swap answers one question
Move coil 1 to a known cylinder and reproduce the condition safely.
If the count does not move, stop swapping and test fuel/mechanical causes.
The original plug should be retained
Fuel wetness, oil ash, coolant cleaning and cracks tell different stories.
Mixing plugs or discarding them destroys cylinder evidence.
Cold diagnosis has a short window
Injector leakage and valve sealing may normalize as temperature changes.
Record the first start rather than diagnosing only after a road test.
Save these scan-data clues
Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.
- Cylinder 1/all-cylinder counts
- RPM, load, ECT and speed
- Fuel correction/pressure
- Plug 1 versus neighboring plugs
- Compression/leak-down
- Recent injector, valve or engine work
A practical diagnostic workflow
- 01Confirm cylinder 1
Do not rely on a generic left/right image.
- 02Preserve cold/load behavior
Test before warm-up hides the pattern.
- 03Inspect plug and boot
Photograph wetness, deposits, cracks and gap.
- 04Perform one coil swap
Watch whether the enhanced count actually moves.
- 05Test injector and sealing
If it stays, prove fuel delivery and compression.
- 06Verify cold and loaded
Repeat the original condition without provoking a flashing MIL.
Do not replace four coils for P0301. A fresh plug may temporarily hide oil, injector or mechanical trouble. Direct-injection fuel circuits require Honda pressure-relief and safety procedures.
Why the model year changes the test
CR-V diagnostics span the first-generation B20, K24-powered second through fourth generations, 1.5L turbo and 2.4L fifth-generation versions, newer 1.5L turbo models and 2.0L hybrid systems. AWD does not create another engine bank, but engine management, direct injection, turbo plumbing, EVAP packaging, VTEC oil hardware and hybrid operating modes change. Confirm the VIN, market, engine, build plant, emissions label and current Honda campaign status before selecting a flowchart or part.
- Cylinder layout is inline-four, but access/routing differs among B20, K24, 1.5T and hybrid engines.
- K24 valve-clearance and timing condition can create cylinder-specific misfire.
- 1.5T direct injection adds high-side pressure and injector leakage tests.
- A flashing MIL requires the same urgent response on AWD and FWD.
P0301 FAQ
Is P0301 always a coil?+
No. Plug, injector, wiring, compression, valve and intake faults can cause it.
Can I drive?+
Not with flashing MIL or severe shaking.
Can I swap coils?+
Yes, carefully, while observing whether the counter follows.
What if it stays on cylinder 1?+
Test injector delivery/circuit and compression.
Can valve clearance cause it?+
Yes, through poor sealing, often temperature-dependent.
Should I clear first?+
No. Preserve counters and freeze data.
Can a runner leak affect one cylinder?+
Yes, especially at idle.
What confirms repair?+
No rising cylinder 1 count under the original condition.
Ford diagnostic references
These documents explain Ford monitor operation. Exact pinpoint tests, connector views and specifications must be selected for the truck's VIN and model year in current service information.
01Honda ServiceExpressHonda VIN-specific service information, DTC flowcharts, wiring and service publications↗02Honda Owners — CR-V manualsOfficial model-year warnings, fuel, maintenance and operating information↗