Code
P0309
Generic
P — Powertrain
Cylinder 9 Misfire Detected
Views:
UK: 37
EN: 58
RU: 45
AI status
Completed
Completed
100%
Causes
- Faulty spark plug in cylinder 9
- Faulty ignition coil or coil pack for cylinder 9
- Clogged, leaking, or electrically faulty fuel injector on cylinder 9
- Low compression or mechanical damage in cylinder 9 (valve, piston, head gasket)
- Faulty wiring or connector to injector or ignition coil
- Vacuum leak near cylinder 9 or intake manifold gasket leak
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration at idle
- Loss of power or poor acceleration
- Higher-than-normal fuel consumption
- Intermittent or persistent misfire P0309 stored
- Possible hard start or stalling
What to check
- Read and record freeze frame data and pending codes; confirm P0309 is current
- Inspect spark plug condition and gap for cylinder 9
- Swap ignition coil from cylinder 9 with another cylinder to see if misfire follows coil
- Swap fuel injector (or use known-good injector) or perform injector balance/flow test
- Perform a compression test or a cylinder leak-down test on cylinder 9
- Check wiring and connectors for coils and injectors for damage, corrosion, or poor contact
Signal parameters
- Misfire detection: increased misfire counter for cylinder 9 reported by ECM
- Crankshaft speed variation waveform on crankshaft position sensor during misfire
- Cylinder 9 short-term fuel trim (STFT) may be high or low relative to others
- Long-term fuel trim (LTFT) changes if misfire persists
- Fuel injector pulse width (ms) for cylinder 9 — should match similar cylinders when commanded
- Primary ignition voltage/coil secondary waveform showing weak spark or no spark
Diagnostic algorithm
- Verify code: Clear codes and perform a test drive to confirm P0309 returns. Note misfire conditions (idle, load, cold).
- Retrieve live data: monitor misfire counters, fuel trims, fuel rail pressure, and sensor data while reproducing misfire.
- Visual inspection: check spark plug, coil, injector wiring and connectors for cylinder 9. Repair any damaged connectors or pin corrosion.
- Ignition swap test: swap the coil (or coil pack lead) from cylinder 9 to another cylinder. If misfire follows the coil, replace the coil.
- Injector test: listen for injector pulse, perform a back-probe to verify injector pulse, and consider swapping injectors or performing an injector flow/balance test.
- Compression/leak-down: perform a compression or leak-down test on cylinder 9 and compare to adjacent cylinders. If low, proceed with mechanical diagnosis (valve, piston rings, head gasket).
- Fuel and air checks: confirm correct fuel pressure and check for vacuum leaks near cylinder 9. Repair as needed.
- Spark plug check/replace: inspect plug for fouling or damage; replace plug if out of spec and retest.
- Check timing and sensors: verify cam/crank timing and inspect cam/crank position sensors and timing components for issues.
- After repairs: clear codes and confirm repair with road test and re-scan. If intermittent, perform extended monitoring or cabin/drive cycle tests.
- Safety note: When testing ignition circuits, use insulated tools and follow manufacturer safety procedures. When performing compression or leak-down tests, follow engine-specific procedures.
Likely causes
- Worn/failed spark plug in cylinder 9
- Failed ignition coil for cylinder 9 (most common on coil-on-plug systems)
- Clogged or failed fuel injector on cylinder 9
- Open/short in wiring or poor connector at coil or injector
- Low compression in cylinder 9 (rings, valves, head gasket)
Fault status
Status
Misfire detected on cylinder 9. ECM recorded inconsistent combustion events for cylinder 9 and set diagnostic trouble code P0309. Investigate ignition, fuel, and mechanical causes specific to cylinder 9.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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Code
P0309
GWM
P — Powertrain
- The order of ignition of 9 cylinders is broken
Views:
UK: 18
EN: 19
RU: 15
AI status
Completed
Completed
100%
Causes
- Faulty spark plug in cylinder 9
- Faulty ignition coil or coil pack for cylinder 9
- Clogged, leaking, or electrically faulty fuel injector on cylinder 9
- Low compression or mechanical damage in cylinder 9 (valve, piston, head gasket)
- Faulty wiring or connector to injector or ignition coil
- Vacuum leak near cylinder 9 or intake manifold gasket leak
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration at idle
- Loss of power or poor acceleration
- Higher-than-normal fuel consumption
- Intermittent or persistent misfire P0309 stored
- Possible hard start or stalling
What to check
- Read and record freeze frame data and pending codes; confirm P0309 is current
- Inspect spark plug condition and gap for cylinder 9
- Swap ignition coil from cylinder 9 with another cylinder to see if misfire follows coil
- Swap fuel injector (or use known-good injector) or perform injector balance/flow test
- Perform a compression test or a cylinder leak-down test on cylinder 9
- Check wiring and connectors for coils and injectors for damage, corrosion, or poor contact
Signal parameters
- Misfire detection: increased misfire counter for cylinder 9 reported by ECM
- Crankshaft speed variation waveform on crankshaft position sensor during misfire
- Cylinder 9 short-term fuel trim (STFT) may be high or low relative to others
- Long-term fuel trim (LTFT) changes if misfire persists
- Fuel injector pulse width (ms) for cylinder 9 — should match similar cylinders when commanded
- Primary ignition voltage/coil secondary waveform showing weak spark or no spark
Diagnostic algorithm
- Verify code: Clear codes and perform a test drive to confirm P0309 returns. Note misfire conditions (idle, load, cold).
- Retrieve live data: monitor misfire counters, fuel trims, fuel rail pressure, and sensor data while reproducing misfire.
- Visual inspection: check spark plug, coil, injector wiring and connectors for cylinder 9. Repair any damaged connectors or pin corrosion.
- Ignition swap test: swap the coil (or coil pack lead) from cylinder 9 to another cylinder. If misfire follows the coil, replace the coil.
- Injector test: listen for injector pulse, perform a back-probe to verify injector pulse, and consider swapping injectors or performing an injector flow/balance test.
- Compression/leak-down: perform a compression or leak-down test on cylinder 9 and compare to adjacent cylinders. If low, proceed with mechanical diagnosis (valve, piston rings, head gasket).
- Fuel and air checks: confirm correct fuel pressure and check for vacuum leaks near cylinder 9. Repair as needed.
- Spark plug check/replace: inspect plug for fouling or damage; replace plug if out of spec and retest.
- Check timing and sensors: verify cam/crank timing and inspect cam/crank position sensors and timing components for issues.
- After repairs: clear codes and confirm repair with road test and re-scan. If intermittent, perform extended monitoring or cabin/drive cycle tests.
- Safety note: When testing ignition circuits, use insulated tools and follow manufacturer safety procedures. When performing compression or leak-down tests, follow engine-specific procedures.
Likely causes
- Worn/failed spark plug in cylinder 9
- Failed ignition coil for cylinder 9 (most common on coil-on-plug systems)
- Clogged or failed fuel injector on cylinder 9
- Open/short in wiring or poor connector at coil or injector
- Low compression in cylinder 9 (rings, valves, head gasket)
Fault status
Status
Misfire detected on cylinder 9. ECM recorded inconsistent combustion events for cylinder 9 and set diagnostic trouble code P0309. Investigate ignition, fuel, and mechanical causes specific to cylinder 9.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Your experience will help others
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Was this AI description helpful?
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Code
P0309
HUMMER
P — Powertrain
Cylinder 9 Misfire Detected
Views:
UK: 17
EN: 29
RU: 28
AI status
Completed
Completed
100%
Causes
- Faulty spark plug in cylinder 9
- Faulty ignition coil or coil pack for cylinder 9
- Clogged, leaking, or electrically faulty fuel injector on cylinder 9
- Low compression or mechanical damage in cylinder 9 (valve, piston, head gasket)
- Faulty wiring or connector to injector or ignition coil
- Vacuum leak near cylinder 9 or intake manifold gasket leak
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration at idle
- Loss of power or poor acceleration
- Higher-than-normal fuel consumption
- Intermittent or persistent misfire P0309 stored
- Possible hard start or stalling
What to check
- Read and record freeze frame data and pending codes; confirm P0309 is current
- Inspect spark plug condition and gap for cylinder 9
- Swap ignition coil from cylinder 9 with another cylinder to see if misfire follows coil
- Swap fuel injector (or use known-good injector) or perform injector balance/flow test
- Perform a compression test or a cylinder leak-down test on cylinder 9
- Check wiring and connectors for coils and injectors for damage, corrosion, or poor contact
Signal parameters
- Misfire detection: increased misfire counter for cylinder 9 reported by ECM
- Crankshaft speed variation waveform on crankshaft position sensor during misfire
- Cylinder 9 short-term fuel trim (STFT) may be high or low relative to others
- Long-term fuel trim (LTFT) changes if misfire persists
- Fuel injector pulse width (ms) for cylinder 9 — should match similar cylinders when commanded
- Primary ignition voltage/coil secondary waveform showing weak spark or no spark
Diagnostic algorithm
- Verify code: Clear codes and perform a test drive to confirm P0309 returns. Note misfire conditions (idle, load, cold).
- Retrieve live data: monitor misfire counters, fuel trims, fuel rail pressure, and sensor data while reproducing misfire.
- Visual inspection: check spark plug, coil, injector wiring and connectors for cylinder 9. Repair any damaged connectors or pin corrosion.
- Ignition swap test: swap the coil (or coil pack lead) from cylinder 9 to another cylinder. If misfire follows the coil, replace the coil.
- Injector test: listen for injector pulse, perform a back-probe to verify injector pulse, and consider swapping injectors or performing an injector flow/balance test.
- Compression/leak-down: perform a compression or leak-down test on cylinder 9 and compare to adjacent cylinders. If low, proceed with mechanical diagnosis (valve, piston rings, head gasket).
- Fuel and air checks: confirm correct fuel pressure and check for vacuum leaks near cylinder 9. Repair as needed.
- Spark plug check/replace: inspect plug for fouling or damage; replace plug if out of spec and retest.
- Check timing and sensors: verify cam/crank timing and inspect cam/crank position sensors and timing components for issues.
- After repairs: clear codes and confirm repair with road test and re-scan. If intermittent, perform extended monitoring or cabin/drive cycle tests.
- Safety note: When testing ignition circuits, use insulated tools and follow manufacturer safety procedures. When performing compression or leak-down tests, follow engine-specific procedures.
Likely causes
- Worn/failed spark plug in cylinder 9
- Failed ignition coil for cylinder 9 (most common on coil-on-plug systems)
- Clogged or failed fuel injector on cylinder 9
- Open/short in wiring or poor connector at coil or injector
- Low compression in cylinder 9 (rings, valves, head gasket)
Fault status
Status
Misfire detected on cylinder 9. ECM recorded inconsistent combustion events for cylinder 9 and set diagnostic trouble code P0309. Investigate ignition, fuel, and mechanical causes specific to cylinder 9.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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Code
P0309
LAND ROVER
P — Powertrain
ignition failure of Cylinder 9 detected
Views:
UK: 15
EN: 25
RU: 21
AI status
Completed
Completed
100%
Causes
- Faulty spark plug in cylinder 9
- Faulty ignition coil or coil pack for cylinder 9
- Clogged, leaking, or electrically faulty fuel injector on cylinder 9
- Low compression or mechanical damage in cylinder 9 (valve, piston, head gasket)
- Faulty wiring or connector to injector or ignition coil
- Vacuum leak near cylinder 9 or intake manifold gasket leak
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration at idle
- Loss of power or poor acceleration
- Higher-than-normal fuel consumption
- Intermittent or persistent misfire P0309 stored
- Possible hard start or stalling
What to check
- Read and record freeze frame data and pending codes; confirm P0309 is current
- Inspect spark plug condition and gap for cylinder 9
- Swap ignition coil from cylinder 9 with another cylinder to see if misfire follows coil
- Swap fuel injector (or use known-good injector) or perform injector balance/flow test
- Perform a compression test or a cylinder leak-down test on cylinder 9
- Check wiring and connectors for coils and injectors for damage, corrosion, or poor contact
Signal parameters
- Misfire detection: increased misfire counter for cylinder 9 reported by ECM
- Crankshaft speed variation waveform on crankshaft position sensor during misfire
- Cylinder 9 short-term fuel trim (STFT) may be high or low relative to others
- Long-term fuel trim (LTFT) changes if misfire persists
- Fuel injector pulse width (ms) for cylinder 9 — should match similar cylinders when commanded
- Primary ignition voltage/coil secondary waveform showing weak spark or no spark
Diagnostic algorithm
- Verify code: Clear codes and perform a test drive to confirm P0309 returns. Note misfire conditions (idle, load, cold).
- Retrieve live data: monitor misfire counters, fuel trims, fuel rail pressure, and sensor data while reproducing misfire.
- Visual inspection: check spark plug, coil, injector wiring and connectors for cylinder 9. Repair any damaged connectors or pin corrosion.
- Ignition swap test: swap the coil (or coil pack lead) from cylinder 9 to another cylinder. If misfire follows the coil, replace the coil.
- Injector test: listen for injector pulse, perform a back-probe to verify injector pulse, and consider swapping injectors or performing an injector flow/balance test.
- Compression/leak-down: perform a compression or leak-down test on cylinder 9 and compare to adjacent cylinders. If low, proceed with mechanical diagnosis (valve, piston rings, head gasket).
- Fuel and air checks: confirm correct fuel pressure and check for vacuum leaks near cylinder 9. Repair as needed.
- Spark plug check/replace: inspect plug for fouling or damage; replace plug if out of spec and retest.
- Check timing and sensors: verify cam/crank timing and inspect cam/crank position sensors and timing components for issues.
- After repairs: clear codes and confirm repair with road test and re-scan. If intermittent, perform extended monitoring or cabin/drive cycle tests.
- Safety note: When testing ignition circuits, use insulated tools and follow manufacturer safety procedures. When performing compression or leak-down tests, follow engine-specific procedures.
Likely causes
- Worn/failed spark plug in cylinder 9
- Failed ignition coil for cylinder 9 (most common on coil-on-plug systems)
- Clogged or failed fuel injector on cylinder 9
- Open/short in wiring or poor connector at coil or injector
- Low compression in cylinder 9 (rings, valves, head gasket)
Fault status
Status
Misfire detected on cylinder 9. ECM recorded inconsistent combustion events for cylinder 9 and set diagnostic trouble code P0309. Investigate ignition, fuel, and mechanical causes specific to cylinder 9.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
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0
Send to email