OBD code information sheet
https://dvireports.com/p0302
Cylinder 2 misfire detected
Selected definitionGeneral catalogue definition1 definitions availableChange
Choose the make reported by the scan tool or vehicle documentation. The same code can have different manufacturer meanings.
Technical explanation
P0302 means the engine controller detected combustion misfires in cylinder 2. Locate cylinder numbering from the engine documentation, not by assumption. The code identifies a combustion event, not a proven defective coil: ignition (where spark ignition exists), injection, mixture or compression can be responsible. Severe misfires may damage the catalytic converter.
Symptoms
Rough idle, hesitation or reduced power.
Engine warning lamp lit or flashing; flashing during active misfires requires stopping safely.
Potential increased consumption, unburned-fuel smell or hard starts on some engines.
Top suspects — what to check first
Suggested checking order, not statistical failure rates or a confirmed diagnosis. Priority can change with the engine and associated codes.
Faulty plug/coil or oil/water in the plug well on spark-ignition engines only.
Check firstFaulty plug/coil or oil/water in the plug well on spark-ignition engines only.
Cylinder 2 injector delivery or control fault, or a fuel-supply problem.
Check nextCylinder 2 injector delivery or control fault, or a fuel-supply problem.
Poor cylinder 2 compression or another mechanical sealing/valve problem.
Check nextPoor cylinder 2 compression or another mechanical sealing/valve problem.
Other possible causes
Local intake leak or mixture/timing concern where related codes support that direction.
Case-dependentLocal intake leak or mixture/timing concern where related codes support that direction.
All causes in the technical record
Some causes overlap with the shortlist above; this is not a probability ranking.
- Faulty plug/coil or oil/water in the plug well on spark-ignition engines only.
- Cylinder 2 injector delivery or control fault, or a fuel-supply problem.
- Poor cylinder 2 compression or another mechanical sealing/valve problem.
- Local intake leak or mixture/timing concern where related codes support that direction.
How to test — practical steps
Start with simple checks before buying parts. This is not a VIN-specific workshop procedure; keep clear of moving parts, fuel pressure and energized circuits.
Safety: Stop safely if the check-engine light flashes or the engine shakes severely. Do not touch energized ignition circuits or open pressurized fuel lines.
- 1
Save fault codes and misfire counters
Save DTCs, freeze-frame and per-cylinder misfire counters if available; note load, temperature and whether other cylinders also misfire.
- 2
Check for flashing lamp or severe shaking
If the MIL flashes or the engine shakes severely, stop safely and avoid further driving: unburned fuel may overheat the catalyst. Do not road-test severe active misfires.
- 3
Locate cylinder 2 from the engine diagram
Identify cylinder 2 from the exact engine layout. Inspect connectors, wiring and oil or water contamination near the relevant ignition/injection parts.
- 4
Petrol: inspect plug and coil with engine off
On spark-ignition engines inspect cylinder 2 plug, insulation and coil with ignition off, comparing part condition and specifications with OEM data. Never touch live high-voltage components.
Detailed tests / equipment needed (advanced)
Perform only tests for which you have the correct wiring diagram, equipment and training.
Distinguish ignition, injection and compression faults
You need:Misfire-capable scannerIgnition system diagramWorkshop electrical/compression tests
- Where the ignition design allows it, a workshop may swap a compatible coil to another cylinder and see whether the misfire follows it. Only then is the coil strongly implicated; do not use this on shared-coil or incompatible designs.
- If ignition is sound or the engine has no spark plugs, test injection using permitted live data and actuator procedures. Electrical and hydraulic injector tests, especially high-pressure systems, require trained personnel.
- If cylinder 2 still misfires, perform a vehicle-specific compression test and if indicated a leak-down test. Low compression points toward mechanical causes, not an automatic plug replacement.
- Repair only the demonstrated fault, clear DTCs and review misfire counters under safe original conditions without provoking severe misfires. Do not replace all cylinder components solely because P0302 was logged.
What you should see: Results must match the applicable engine-specific test conditions and limits. One reading does not prove a component has failed.
Electrical, fuel, exhaust or timing measurements require suitable equipment and must not be improvised.
Full technical diagnosis — additional checks
Step-by-step diagnosis
ChecksWork through the steps before replacing parts. Adapt the checks to the manufacturer’s procedure.
1. Save DTCs, freeze-frame and per-cylinder misfire counters if available; note load, temperature and whether other cylinders also misfire.
2. If the MIL flashes or the engine shakes severely, stop safely and avoid further driving: unburned fuel may overheat the catalyst. Do not road-test severe active misfires.
3. Identify cylinder 2 from the exact engine layout. Inspect connectors, wiring and oil or water contamination near the relevant ignition/injection parts.
4. On spark-ignition engines inspect cylinder 2 plug, insulation and coil with ignition off, comparing part condition and specifications with OEM data. Never touch live high-voltage components.
5. Where the ignition design allows it, a workshop may swap a compatible coil to another cylinder and see whether the misfire follows it. Only then is the coil strongly implicated; do not use this on shared-coil or incompatible designs.
6. If ignition is sound or the engine has no spark plugs, test injection using permitted live data and actuator procedures. Electrical and hydraulic injector tests, especially high-pressure systems, require trained personnel.
7. If cylinder 2 still misfires, perform a vehicle-specific compression test and if indicated a leak-down test. Low compression points toward mechanical causes, not an automatic plug replacement.
8. Repair only the demonstrated fault, clear DTCs and review misfire counters under safe original conditions without provoking severe misfires. Do not replace all cylinder components solely because P0302 was logged.
Components to check
This list does not confirm failed components and is not a replacement recommendation. Verify the fault cause and vehicle applicability first.
- Inspect based on engine design: cylinder 2 plug/coil/wiring if spark ignition is fitted, injector and connector, or mechanical sealing components only after confirmation.
Make- and engine-specific notes
Documented configurations, not proven common defects for all makes or engines. Selecting a vehicle narrows the results.
No reviewed engine-specific exception is available for the selected configuration. Use only the general checks and obtain the exact engine procedure.
Notes are diagnostic leads, not proven faults or disassembly instructions. Do not work on brakes, fuel systems or hot components without proper training.
Check the fuses before ordering a part
An OBD code describes a detected condition; it does not tell you which part to replace. Start with the fuse for the affected circuit.
If the fuse is good, carry on like this:
- Check the relevant supplies and connectionsWhere the diagnostic procedure calls for electrical checks, verify supply, ground and connectors under the manufacturer’s activation conditions.
- Run the specified component testUse the manufacturer’s test for this code and component before deciding it has failed.
- Order only after the fault is demonstratedReplace a part only when the prescribed tests identify it as defective.
Check details
- Identify the circuit and any relevant fuse: Confirm the vehicle, engine, code meaning and stored operating conditions first. A fuse link is a location aid, not evidence that the fuse caused this code. Use the specified type and rating; do not repeatedly replace a fuse that opens.
- Check the relevant supplies and connections: Use the specified engine state, circuit conditions and expected values. Have live measurements performed by someone qualified. For non-electrical faults, follow the relevant mechanical, fluid, pressure or leak checks instead.
- Run the specified component test: Do not apply a generic resistance range. Any resistance or continuity test requires a de-energized circuit and an isolated component, with the correct pins and temperature from the procedure. Some components need a different kind of test.
- Order only after the fault is demonstrated: If results are normal, continue the relevant wiring, control, mechanical or intermittent diagnosis. Check for related faults and verify the repair under the required conditions. A code or a completed checklist alone does not justify replacement.
If the procedure involves airbag/SRS, pretensioners or a high-voltage system, stop DIY testing and use qualified service. Do not probe these circuits with a multimeter.
Vehicle experiences and cases
User-reported cases published after moderation. Approval does not verify the diagnosis; the same code can have different causes.
No experiences have been published for this definition yet. You can be the first to share the checks and outcome.
See all vehicle experiencesManuals, components and vehicle guides
Find the relevant procedure in the workshop manual for your vehicle. A fault code alone does not identify a failed part, powertrain or exact schematic.
Manuals open at their original source. Exact diagram availability depends on the build year, engine and manufacturer access.
System and diagnostic diagrams
Conceptual illustrations of the system; verify the actual configuration and tests in vehicle-specific documentation.
Misfire and cylinder combustion
Illustrative petrol-engine ignition example. Original conceptual diagram, not an exact component location or an OEM repair procedure.
View full-size diagram →Can I fix it myself?
Once the cause is confirmed, open the job sheet: difficulty, time, tools, parts and steps. Common jobs for P0302:
How to fix P0302: step-by-step guide
Symptoms, causes, visual inspection, scan-tool or multimeter tests, replacement and clearing the code, with safety warnings.
Irregular combustion and misfire
General system guidance · not a confirmed diagnosis
Misfire may arise from ignition, fuelling or mechanical condition. Confirm cylinder numbering for the exact engine.
The association is based on the imported description. This information explains the system; it does not confirm a procedure for the exact code, model or engine. Verify applicability in manufacturer documentation.
Checks for this type of system
- Save codes and compare affected cylinders.
- Check spark ignition only on engines equipped with it.
- Separate injection, intake and compression concerns through workshop tests.
Useful diagnostic data, where available
- Per-cylinder misfire counts where supported.
- Fuel trims and occurrence conditions.
Normal values and thresholds vary by vehicle and are not assumed here.
Mistakes to avoid
- Not every misfire is a failed coil.
- Do not apply spark-plug tests to diesels.
System-guide sources
References support general principles, not individual verification of every associated code.
Continue your research
Links to related systems, warning lights and vehicle examples.
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