P0301: Falha de Combustão Detectada no Cilindro 1
O Código de Falha de Diagnóstico (DTC) P0301 indica que o Módulo de Controle do Motor (ECM/PCM) detectou uma falha de combustão completa ou intermitente isolada especificamente no Cilindro 1. Em um motor diesel de rampa comum - que dispensa sistema de ignição por centelha -, a identificação da falha é calculada exclusivamente pelo sensor de posição da árvore de manivelas (CKP) de alta resolução, monitorando variações submicrométricas na velocidade angular do virabrequim. Quando o tempo de combustão/expansão do Cilindro 1 (30° a 90° após o ponto morto superior / PMS) resulta em uma queda de desaceleração rotacional em vez de uma aceleração angular acima dos parâmetros calibrados (geralmente >2,0% dos eventos de combustão monitorados), o código P0301 é gravado.
🚗 Segurança operacional, custos típicos e verificação
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🚦 Segurança de condução e risco mecânico
Avaliação imediata e necessidade de reboqueFalha de combustão cilindro 1 - Risco de fusão do catalisador e lavagem do cilindro
O cilindro 1 parou de realizar combustão, provocando vibrações fortes e perda de potência. Luz intermitente: desligue o motor imediatamente para evitar danos graves.
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💰 Orçamento típico de oficina
Níveis de custo previstos para peças e mão de obraManutenção menor / Filtro25 € - 95 € (Vela / bobina cilindro 1)Limpeza de sensor, troca do filtro de combustível, verificação de fusíveis ou chicote elétrico.
Substituição válvula / Sensor180 € - 450 € (Descarbonização de válvulas ou ultrassom de injetor)Substituição de componente individual (válvula reguladora, unidade dosadora ou injetor remanufaturado).
Reparação maior / Bomba e injetores350 € - 1.200 € (Injetor de injeção direta OEM)Revisão de bomba de alta pressão, jogo de injetores novos ou substituição do conjunto DPF.
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🧰 Verificações visuais rápidas na garagem
Diagnóstico em 5 minutos sem ferramentas antes de chamar o reboque1Inspecione o conector elétrico do injetor do Cilindro 1: Desconecte a trava plástica, verifique se há presença de oxidação esverdeada (azinhavre) ou pinos fêmea frouxos e reconecte firmemente até o clique.2Cheire a vareta de nível de óleo do motor: Se houver forte cheiro de óleo diesel ou se o nível estiver subindo além da marca MÁX, há combustível não queimado lavando as camisas e contaminando o cárter - não ligue o motor.3Inspecione a linha de alimentação de baixa pressão: Verifique se há bolhas de ar visíveis na tubulação durante a marcha lenta, o que induz leituras falsas na unidade doseadora e instabilidade de pressão na rampa comum. - 04
🛡️ Escudo contra diagnósticos errados na oficina
Perguntas técnicas para evitar substituição desnecessária de peças"Diga: 'Antes de condenar o injetor, realize um teste de correção de vazão dos cilindros (balanceamento de cilindro) via scanner e faça o teste de volume na linha de retorno de injetores em bancada ou com provetas.'"
"Diga: 'Poderia inverter o injetor do Cilindro 1 com o do Cilindro 2 antes da troca para confirmar se a falha de combustão acompanha o injetor fisicamente ou se permanece no cilindro por falta de compressão?'"
Nota técnica: Faça estas perguntas ao mecânico antes de aprovar orçamentos elevados:
Triagem de oficina em 30 segundos
- Violent engine shaking, severe vibration, and rhythmic thumping at idle (running distinctly on 3 cylinders)
- Flashing or steady Check Engine Light (MIL) on dashboard, accompanied by flashing glow plug light and ESP/traction warning
- Massive loss of engine power, sluggish throttle response, and inability to accelerate up highway gradients
- Completely failed Cylinder 1 fuel injector (blown solenoid coil, seized command piston, or cracked nozzle needle)
- Low mechanical cylinder compression on Cylinder 1 caused by a burnt exhaust valve, broken rocker arm, or holed piston
- Burned-out or heavily carbon-crusted Cylinder 1 glow plug preventing compression ignition during cold ambient starts
Connect scan tool live telemetry: compare Target Fuel Rail Pressure vs Actual Rail Pressure and log metering valve command PWM duty cycle during idle and road load.
Expensive Diagnostic Pitfall & Technical Reality
P0301 proves that Cylinder 1 has suffered catastrophic mechanical valve or piston damage, or that all 4 common rail injectors must be replaced ($1,800 - $3,500).
Diesel engines detect misfires electronically by measuring crankshaft acceleration deceleration via the CKP sensor following Cylinder 1's TDC firing event. In over 80% of verified common rail P0301 cases, cylinder mechanical compression is completely sound. The root failure is typically a blown copper combustion sealing washer allowing compression blowout ('Black Death' tar buildup around injector 1), an injector electrical connector with spread terminal tension caused by engine vibration, or severe hydraulic needle stickiness from fuel lacquer deposits.
Unnecessary engine teardown or replacing all 4 injectors ($2,200+) vs replacing the $3 copper crush washer, re-cutting the seat with a hand reamer ($45 tool), or tensioning connector terminal pins ($0), saving over $2,000.
Motores e plataformas de injeção mais afetados
Este código de falha afeta principalmente as seguintes plataformas diesel common rail. Consulte a família do motor para falhas típicas e números de peças de reposição:
Volkswagen / Audi 2.0 TSI EA888 Gen 3 (GTI, Golf R, Audi A4, Q5)
Bosch HDEV5.2 GDI Direct InjectionSintoma típico: Flashing EPC light under highway passing acceleration, violent cold morning idle shake, raw fuel smell in exhaust.
Falha típica de fábrica: Cylinder 1 Bosch multi-hole direct fuel injector sticking closed from carbon varnish or weeping fuel overnight; heavy carbon buildup on Cylinder 1 intake valve tulip.
06L906036K / Bosch 0261500162 (Injector)BMW 2.0T N20 & 3.0T N55 (320i, 328i, 528i, 335i, 535i, X3, X5)
Bosch HDEV5 Solenoid Direct InjectionSintoma típico: Drivetrain Malfunction message on iDrive, engine misfiring severely on cold morning start, black soot on exhaust tips.
Falha típica de fábrica: Cylinder 1 direct injector internal pintle wear allowing pressurized rail fuel to weep into combustion chamber during engine rest, fouling spark plug.
13647597870 / Bosch 0261500109 (Injector)Mercedes-Benz 3.0T & 3.5L V6 M276 (C400, E400, ML350, GL450, S550e)
Bosch Piezo / Solenoid Direct Injection (200 bar)Sintoma típico: Check Engine Light illuminated with severe rough running under heavy towing or kickdown acceleration.
Falha típica de fábrica: Cylinder 1 high-pressure fuel injector nozzle tip carbon fouling disrupting spray cone atomization, causing localized lean flameout.
A2760700587 / Bosch 0261500065 (Injector)Honda Civic Type R K20C1 & Accord 2.0T (FK8, FL5)
Keihin Direct Cylinder Injection (200 bar)Sintoma típico: VSA warning lamp and P0301 stored after high-RPM track sessions; rough idle with momentary stumbling.
Falha típica de fábrica: Cylinder 1 high-flow direct injector micro-filter screen debris restriction or injector seal ring combustion blow-by.
16450-5BF-A01 / 16010-5BF-305 (Injector)Toyota & Lexus 2.0T 8AR-FTS (IS200t, GS200t, NX200t, RX200t, Crown)
Toyota D-4S Dual Injection (GDI Direct + Port)Sintoma típico: Hesitation during transition from low-speed port injection to high-pressure direct cylinder injection mode.
Falha típica de fábrica: Cylinder 1 in-cylinder high-pressure direct injector nozzle tip varnish, leading to poor atomization under high load.
23209-39145 / Denso GDI InjectorCylinder Balance & Injector Deviation Guide
Common rail diesel cylinder balance & smooth running diagnostic guide. Balance rates, mg/stroke deviation, P0263 misfire, compression vs injector test.
Circuito de comando e lógica do atuador
1. Dynamic In-Demand Fuel Metering
Diesel compression ignition requires three mandatory physical conditions: high cylinder compression (>22 bar producing air temperatures above 500°C), precise atomization of high-pressure diesel fuel (>250 bar cranking, >1400 bar running), and exact injection timing. The ECM tracks the rotational speed of the flywheel tone ring (60-2 or 36-2). When Cylinder 1 fires correctly, crankshaft rotational speed accelerates sharply. If combustion fails completely (zero heat release), the drag of compressing air causes the crankshaft to slow down rapidly during Cylinder 1's segment, triggering the misfire monitor.
2. Closed-Loop PID Deviation Monitoring
The ECM evaluates misfire data across two independent severity windows: 1. Catalyst / DPF Damaging Window (200 engine revolutions): If the misfire rate is severe enough to allow raw fuel into the exhaust (causing DPF melting), the Check Engine Light flashes violently. 2. Emissions Compliance Window (1,000 engine revolutions): If misfire percentage exceeds 2.0% to 3.0%, a continuous DTC P0301 is logged. The ECM attempts initial compensation by adding fuel via Smooth Running Control (SRC); if the cylinder fails to respond, the ECM cuts fuel to Cylinder 1 to prevent catalytic converter destruction.
3. Diagnostic Trap: Normally Open (NO) vs Normally Closed (NC) Valves
Misfire (P0301) vs Balance Contribution (P0263) Diagnostic Rule: P0263 indicates PARTIAL combustion (the cylinder is running but producing less torque due to coked nozzle holes or minor leakage). P0301 indicates a COMPLETE DEAD MISS: Cylinder 1 has suffered complete combustion failure. In diesel workshops, a dead miss on a single cylinder is caused by one of three primary failures: 1. Complete injector failure (blown solenoid coil, zero fuel injection); 2. Major mechanical compression loss (bent valve, holed piston, broken rocker arm); or 3. Cold-start glow plug burn-out preventing ignition in cold ambient temperatures.
Parâmetros físicos elétricos e hidráulicos
Protocolo de Diagnóstico de Oficina Passo a Passo
Injector Cross-Swap Physical Verification (Hardware vs Mechanics)
Remove the Cylinder 1 fuel injector and swap it with Cylinder 2 (using brand-new annealed copper crush washers). Reprogram the respective IMA/QR calibration codes into the ECM via scan tool. Clear trouble codes and start the engine. If the misfire code moves from P0301 to P0302 (Cylinder 2), the injector has an internal mechanical/hydraulic failure: replace it. If the misfire remains stubbornly on Cylinder 1 (P0301), the problem is 100% mechanical (compression/valvetrain) or wiring.
Electronic Relative Compression & Mechanical Gauge Test
Execute an electronic 'Relative Compression Test' via diagnostic scan tool, which monitors starter current draw and crankshaft angular speed across each cylinder's compression stroke. If Cylinder 1 shows <85% relative compression, remove the Cylinder 1 glow plug and thread in a physical diesel mechanical compression gauge. Crank engine: compression must exceed 22 bar (320 psi) with <3 bar variance to companion cylinders. A reading below 18 bar confirms blown piston rings, burnt valves, or a blown head gasket.
Individual Injector Backleak (Return Flow) Measurement
Disconnect the low-pressure fuel return lines from all injectors. Attach graduated transparent test tubes to the return nipples. Crank the engine for 15 seconds (or run at warm idle for 2 minutes). A healthy injector returns less than 20-25 mL at idle. If Cylinder 1 returns excessive fuel (>40 mL) or fills the bottle instantly during cranking, its internal control valve has collapsed, dumping rail pressure and preventing the needle from lifting.
Injector Solenoid Coil Resistance & 250V Megohmmeter Test
Disconnect the Cylinder 1 injector harness. Using a precision digital multimeter on the 200 Ω scale, measure coil resistance: solenoid injectors must measure 0.20 Ω to 0.45 Ω @ 20°C; piezo injectors must measure 180 kΩ to 220 kΩ. Next, test insulation resistance to the metal body with an automotive insulation tester set to 250V/500V test voltage (must exceed >10 MΩ). A low reading confirms high-voltage dielectric breakdown arcing into the cylinder head.
Glow Plug Resistance & Power Feed Audit (Cold Start Misfires)
If the P0301 misfire occurs exclusively during the first 3 to 5 minutes following a cold start, disconnect the Cylinder 1 glow plug lead. Measure resistance between the glow plug center terminal and engine cylinder block ground. A healthy glow plug measures 0.4 Ω to 1.2 Ω. An open circuit (infinite resistance / OL) confirms a burned-out glow plug that leaves Cylinder 1 too cold to ignite diesel.
Cylinder 1 Valvetrain & Camshaft Lobe Inspection
Remove the engine valve/camshaft cover. Visually inspect the intake and exhaust camshaft lobes and roller rocker arms for Cylinder 1. Look for worn, flattened camshaft lobes (very common on high-mileage VAG TDI and Ford engines) or collapsed hydraulic lash adjusters. A flattened intake cam lobe prevents the intake valves from opening fully, starving the cylinder of oxygen.
Reparo de hardware e lista de peças BOM
Isolate localized ignition, intake valve carbon coking, and direct injector weeping before replacing major engine assemblies:
0261500162 / 06L906036KBosch
OEM multi-hole high-pressure direct fuel injector. Restores optimal conical spray geometry and eliminates Cylinder 1 misfire.
0261500109 / 13647597870Bosch
Original factory solenoid direct fuel injector. Cures cold morning cylinder wash and persistent Cylinder 1 misfire stumble.
0261500065 / A2760700587Bosch
High-precision CGI direct fuel injector assembly for Mercedes BiTurbo V6 platforms. Eliminates high-load misfires.
16450-5BF-A01 / 16010-5BF-305Keihin
OEM factory high-flow direct injector. Resolves high-RPM fuel starvation and Cylinder 1 combustion cut.
23209-39145 / 23209-31105Denso
Original equipment direct-in-cylinder fuel injector with Teflon seal ring for D-4S twin-injection platforms.
Calculadora interativa de tolerâncias Common Rail
Componentes de injeção associados
The following genuine OEM fuel pumps and common rail injectors are verified factory equipment for engines reporting fault protocol P0301. Cross-reference operating pressures and tightening torques before sub-assembly replacement:
095000-5880Denso
095000-5880 Denso Toyota 2KD-FTV Injector: 23670-30050 Data
View Technical Specs & Fitment →28337917Delphi
28337917 Delphi Bobcat D24 Injector: 7030364 Specs & Data
View Technical Specs & Fitment →095000-8340Denso
095000-8340 Denso Mitsubishi 4D56 HP Injector: 1465A367 Data
View Technical Specs & Fitment →0445120289Bosch
0445120289 Bosch Perkins 1104D Injector: 2645A749 Data
View Technical Specs & Fitment →0445120357Bosch
0445120357 Bosch Cummins ISDe 6.7L Injector: 4988835 Data
View Technical Specs & Fitment →0445110594Bosch
0445110594 Bosch VW 1.6 TDI Injector: 03L130277S Data
View Technical Specs & Fitment →Reset de adaptação da bomba e ciclo de aprendizado
Following replacement of the Cylinder 1 fuel injector, glow plug, or cylinder head servicing, execute the adaptation routine:
1. Enter the new 6-to-30 digit alphanumeric calibration code (IMA/QR code) stamped on the top of the new Cylinder 1 injector into the ECM via scan tool.
2. Clear all stored diagnostic trouble codes and confirm engine coolant temperature is above 75°C (167°F).
3. Access scan tool 'Engine Control Module' -> 'Special Functions' -> select 'Reset Cylinder Balance / Smooth Running Values'.
4. Start the engine and allow it to idle undisturbed in park/neutral for 5 minutes without touching any pedals, allowing the ECM to build initial torque offsets.
5. Accelerate vehicle smoothly in 4th gear to 80 km/h (2200 RPM), then release throttle completely to coast down in gear to 35 km/h (minimum 8s overrun).
6. Repeat this acceleration and coast-down sequence 5 times. Return to workshop and confirm Cylinder 1 misfire counter remains at absolute zero.
Diagnóstico diferencial e avarias associadas
Random or Multiple Cylinder Misfire Detected
Multi-cylinder misfire code triggered when systemic issues (air in fuel, bad fuel, low rail pressure) cause misfiring across multiple cylinders.
Cylinder 1 Contribution/Balance Fault
Milder predecessor fault indicating Cylinder 1 is producing degraded torque; if contribution degrades further into complete flameout, P0301 triggers.
Injector Circuit/Open - Cylinder 1
Electrical circuit fault code on Cylinder 1; if an injector wiring open/short develops, P0201 will trigger alongside or override P0301.
Casos reais de oficina
2014 Mercedes-Benz C220 CDI (W204 OM651)(185,000 km)
Perguntas técnicas frequentes
O que significa o código de avaria P0301?
O Código de Falha de Diagnóstico (DTC) P0301 indica que o Módulo de Controle do Motor (ECM/PCM) detectou uma falha de combustão completa ou intermitente isolada especificamente no Cilindro 1. Em um motor diesel de rampa comum - que dispensa sistema de ignição por centelha -, a identificação da falha é calculada exclusivamente pelo sensor de posição da árvore de manivelas (CKP) de alta resolução, monitorando variações submicrométricas na velocidade angular do virabrequim. Quando o tempo de combustão/expansão do Cilindro 1 (30° a 90° após o ponto morto superior / PMS) resulta em uma queda de desaceleração rotacional em vez de uma aceleração angular acima dos parâmetros calibrados (geralmente >2,0% dos eventos de combustão monitorados), o código P0301 é gravado.
Quais são os sintomas mais comuns de P0301?
Violent engine shaking, severe vibration, and rhythmic thumping at idle (running distinctly on 3 cylinders), Flashing or steady Check Engine Light (MIL) on dashboard, accompanied by flashing glow plug light and ESP/traction warning, Massive loss of engine power, sluggish throttle response, and inability to accelerate up highway gradients, Dense clouds of white or blue-grey exhaust smoke on cold start (raw unburned atomized diesel fuel vapor), Overwhelming raw diesel exhaust odor noticeable around the vehicle and through cabin air vents, Scan tool live data shows Cylinder 1 misfire counter incrementing rapidly (>50 counts per 1000 revolutions).
O que causa P0301 em um motor diesel?
Completely failed Cylinder 1 fuel injector (blown solenoid coil, seized command piston, or cracked nozzle needle); Low mechanical cylinder compression on Cylinder 1 caused by a burnt exhaust valve, broken rocker arm, or holed piston; Burned-out or heavily carbon-crusted Cylinder 1 glow plug preventing compression ignition during cold ambient starts; Broken, corroded, or shorted wiring harness wire between the ECM and the Cylinder 1 fuel injector connector; Internal low-side power MOSFET driver transistor failure for Cylinder 1 inside the Engine Control Module (ECM); Intake valve carbon choking or stuck-shut intake swirl flap starving Cylinder 1 of necessary fresh air charge.
É seguro dirigir com o código P0301 ativo?
🟡 Cuidado: Modo de segurança / Visitar oficina
Quanto custa reparar o código de falha P0301?
Os custos típicos de reparação para o código P0301 dependem da causa raiz e do nível de intervenção: Nível 1 (Manutenção ligeira / DIY): 25 € - 95 € (Vela / bobina cilindro 1) (Limpeza de sensor, troca do filtro de combustível, verificação de fusíveis ou chicote elétrico.); Nível 2 (Substituição de componente): 180 € - 450 € (Descarbonização de válvulas ou ultrassom de injetor) (Substituição de componente individual (válvula reguladora, unidade dosadora ou injetor remanufaturado).); Nível 3 (Subconjunto principal): 350 € - 1.200 € (Injetor de injeção direta OEM) (Revisão de bomba de alta pressão, jogo de injetores novos ou substituição do conjunto DPF.). Valores de referência de oficinas. Mais de 70% das ocorrências são resolvidas no Nível 1 ou 2 sem substituição de subconjuntos inteiros.
Can a bad glow plug cause code P0301 in a diesel engine?
Yes, but specifically during cold starts and the first 3 to 5 minutes of engine warm-up. Unlike gasoline spark plugs which fire continuously, diesel glow plugs only operate during pre-glow and post-glow phases to keep cold cylinder walls warm. If the Cylinder 1 glow plug is burned out, cold compression cannot reach the 500°C auto-ignition temperature of diesel, causing Cylinder 1 to misfire (P0301) and puff white unburned fuel smoke until the cylinder block heats up.
Why does my diesel car misfire on Cylinder 1 under heavy load but idle fine?
At idle, common rail fuel pressure is only 250 to 350 bar, and the injector needs to deliver only a tiny 5 mg micro-pulse. Under full load, rail pressure spikes to 1800+ bar and fuel delivery increases tenfold. If the Cylinder 1 injector has internal control valve wear (excessive backleak) or a partially clogged nozzle, it can deliver enough fuel at low pressure to idle smoothly, but completely fails to deliver the massive volume demanded at 1800 bar, dropping cylinder torque and triggering P0301.
What is the fastest way to confirm whether the Cylinder 1 injector is bad?
The most reliable test is the physical cross-swap. Remove the Cylinder 1 injector and swap it with Cylinder 2 (always install new annealed copper seating washers). Enter the calibration codes into the scan tool and drive the vehicle. If the misfire moves to Cylinder 2 (P0302), you have 100% proven the injector is defective. If the misfire stays on Cylinder 1 (P0301), you know the injector is innocent and must check mechanical cylinder compression.