All Powertrain Ignition DTC Codes — Complete OBD-II Diagnostic Guide (2026)
This comprehensive reference covers every Powertrain Ignition diagnostic trouble code (DTC) — 31 codes total. Each code includes what triggers it, common symptoms, step-by-step diagnostic procedures, and repair guidance.
Detailed DTC Code Guides
P0300: The engine control module has detected that one or more cylinders are misfiring, but it cannot pinpoint a single cylinder. The misfires occur randomly across the engine, indicating a problem that affects the ignition or fuel delivery system as a whole.
Fix OBD-II code P0300: Random/Multiple Cylinder Misfire Detected. Step-by-step diagnosis and repair guide.
- Visual inspection and quick checks
- Scan live data and freeze‑frame information
- Check ignition components
- ...see all 6 steps →
P0301: The engine control module sensed that cylinder 1 failed to fire at the proper time during at least one of the last three cycles. This usually means the spark, fuel, or compression in that cylinder is out of spec.
Fix OBD-II code P0301: Cylinder 1 Misfire Detected. Step-by-step diagnosis and repair guide.
- Visual and Quick Check
- Live Data Scan for Misfire Counts
- Spark Plug & Ignition Coil Inspection
- ...see all 5 steps →
P0302: The engine control module has measured a drop in combustion pressure in cylinder 2, meaning spark, fuel, or compression is missing. When the ECM detects this, it stores P0302 and may cause a rough idle, loss of power, or higher emissions.
Fix OBD‑II code P0302: Cylinder 2 Misfire Detected. Step‑by‑step diagnosis, repair costs, emissions impact, and safe‑driving advice.
- Visual and Quick Scan
- Spark Plug & Ignition Coil Check
- Fuel Injector Inspection
- ...see all 5 steps →
P0303: The engine control module has sensed that cylinder 3 is not completing its combustion cycle properly. This usually shows up as a rough idle, shaking, or a loss of power when you accelerate.
Fix OBD-II code P0303: Cylinder 3 Misfire Detected. Step-by-step diagnosis and repair guide.
- Visual & Quick Check
- Scan Live Data & Freeze‑Frame
- Spark Plug & Ignition Coil Test
- ...see all 6 steps →
P0304: The engine control module has sensed that cylinder 4 is not completing its combustion cycle properly. This usually means the spark isn’t firing, the fuel isn’t being delivered, or the compression is too low for that cylinder.
Fix OBD-II code P0304: Cylinder 4 Misfire Detected. Step-by-step diagnosis and repair guide.
- Quick Visual Scan
- Read Freeze‑Frame Data
- Spark Plug Inspection
- ...see all 7 steps →
P0305: The powertrain control module has recorded that cylinder 5 fails to complete its combustion event. The misfire may stem from weak spark, insufficient fuel, or a mechanical fault inside the cylinder.
Step‑by‑step guide to fixing OBD‑II code P0305. Learn why cylinder 5 misfires, how to test spark plugs, coils, injectors, compression and what it costs.
- Visual Inspection & Loose Connections
- Spark Plug & Ignition Coil Check
- Fuel Injector Operation Test
- ...see all 5 steps →
P0306: The engine control module has sensed that cylinder 6 is not firing correctly. This usually means the spark, fuel, or compression in that cylinder is weak or missing, causing a rough idle and reduced power.
Fix OBD-II code P0306: Cylinder 6 Misfire Detected. Step-by-step diagnosis and repair guide.
- Quick Visual Scan
- Inspect Spark Plug & Ignition Coil
- Live Data Check – Cylinder Contribution
- ...see all 6 steps →
P0307: The engine control module has noticed that cylinder 7 is not completing its combustion cycle properly. This usually shows up as a rough idle, shaking, or loss of power because the spark or fuel isn’t arriving at the right time.
Fix OBD-II code P0307: Cylinder 7 Misfire Detected. Step-by-step diagnosis and repair guide.
- Visual inspection of obvious items
- Check cylinder 7 spark plug
- Test ignition coil or coil‑on‑plug (COP) for cylinder 7
- ...see all 6 steps →
P0308: The engine control module has detected that cylinder 8 is not completing its combustion cycle correctly. The result is a rough idle, loss of power, or increased emissions.
Learn how to diagnose and repair OBD‑II code P0308 – Cylinder 8 Misfire Detected. Step‑by‑step checks, safety tips, cost estimates, and emissions impact.
- Quick visual inspection
- Live data scan
- Spark plug & coil test
- ...see all 5 steps →
P0316: The P0316 code indicates that the engine control module has detected a misfire in one or more cylinders during the first 1000 revolutions of engine startup. This can be caused by a variety of factors, including faulty spark plugs, ignition coil issues, or fuel system problems. The code is triggered when the engine control module detects a misfire rate that exceeds a certain threshold during the initial startup phase.
Fix P0316 code with our DIY guide. Learn how to diagnose and repair engine misfire detected on startup, common in Toyota, Honda, and Ford vehicles. Get cost...
- Step 1: Check for Loose or Faulty Spark Plugs
- Step 2: Inspect the Ignition Coil and Boot
- Step 3: Check the Fuel System for Leaks or Blockages
P0325: The engine control module has detected an abnormal signal from the knock sensor on bank 1. Either the sensor isn’t sending a voltage, the wiring is shorted/open, or the sensor itself has failed. The ECU then retards ignition timing to protect the engine.
Fix OBD‑II code P0325: Knock Sensor 1 Circuit Malfunction (Bank 1). Step‑by‑step diagnosis, repair guide, cost guide, and safety tips.
- Visual inspection of sensor and wiring
- Scan live data and freeze‑frame
- Measure sensor voltage with a digital multimeter
- ...see all 6 steps →
P0326: The engine control module reports that the voltage signal from Knock Sensor 1 on Bank 1 is outside the calibrated range. This usually points to a faulty sensor, damaged wiring, or a problem in the PCM’s input circuit.
Find out what the P0326 trouble code means, how it affects engine performance and emissions, and follow a step‑by‑step DIY repair plan with safety tips and...
- Visual inspection for obvious problems
- Read live data and freeze‑frame info
- Check sensor power and ground circuits
- ...see all 5 steps →
P0330: The engine control module (ECM) has detected an abnormal signal or no signal from the knock sensor on bank 2. The sensor’s circuit is either open, shorted, or providing out‑of‑range data, so the ECM can’t use knock feedback to adjust timing.
P0330 knock sensor 2 circuit malfunction. Causes, diagnosis, sensor location tips, parts, repair cost, and step-by-step fix guide.
- Visual inspection for loose connections or damaged wiring
- Scan live data and freeze‑frame information
- Measure sensor resistance with a digital multimeter
- ...see all 6 steps →
P0332: P0332 indicates that the PCM receives a voltage lower than the calibrated minimum from Knock Sensor 2 on bank 2. The condition often leads to misfires, rough idle, and reduced power.
Step‑by‑step instructions for diagnosing and fixing OBD‑II code P0332. Includes safety tips, cost estimates, emissions impact, and model‑specific notes.
- Step 1 – Visual Scan
- Step 2 – Live Data Review
- Step 3 – Voltage Test
- ...see all 5 steps →
P0335: The engine control module (ECM) has detected an abnormal signal from the crankshaft position sensor (CKP) circuit labeled “A.” In plain English, the computer isn’t getting a reliable reading of crankshaft speed or position, so it can’t time spark and fuel correctly.
Fix OBD-II code P0335: Crankshaft Position Sensor A Circuit Malfunction. Step-by-step diagnosis and repair guide.
- Visual Inspection – Loose Connections & Damaged Wiring
- Check for Faulty Sensor Power Supply
- Read Live Data – Crankshaft Position Signal
- ...see all 5 steps →
P0336: The engine control module sees a voltage signal from the crankshaft position sensor that is out of the expected range or is too erratic. In plain English, the sensor isn’t telling the computer how fast the crank is turning, so the ECU can’t time the spark correctly.
Fix OBD-II code P0336: Crankshaft Position Sensor A Circuit Range/Performance. Step-by-step diagnosis and repair guide.
- Visual inspection of wiring and connectors
- Battery voltage check
- Crankshaft sensor signal test
- ...see all 6 steps →
P0340: The PCM cannot read a valid signal from the camshaft position sensor B on Bank 1. This usually means a wiring fault, a bad sensor, or timing that’s out of spec, and the engine may run unevenly or stall.
Learn what P0340 means, why it appears, and how to fix the camshaft position sensor circuit on Bank 1. Get cost estimates, safety tips, and step‑by‑step DIY...
- Inspect connectors and wiring
- Measure sensor voltage
- Check ground continuity
- ...see all 6 steps →
P0341: The engine control module receives a camshaft‑position signal from bank 1 that is outside the calibrated range. The fault usually points to a bad sensor, damaged wiring, or cam timing that is out of spec.
Fix OBD‑II code P0341: Camshaft Position Sensor Circuit Range/Performance (Bank 1). Step‑by‑step diagnosis, repair guide, cost guide, and safety tips.
- Visual Inspection of Connectors and Wiring
- Scan Live Data and Verify Sensor Signal
- Measure Sensor Voltage with a Digital Multimeter
- ...see all 5 steps →
P0345: The ECM does not receive a valid voltage signal from Camshaft Position Sensor A on bank 2, preventing accurate fuel‑injection and spark timing.
Step‑by‑step guide for OBD‑II DTC P0345. Learn how to test the camshaft‑position sensor, wiring, and timing on bank 2, plus cost estimates and emissions impact.
- Visual inspection of connectors and wiring
- Scan live data for sensor voltage
- Resistance test of the sensor
- ...see all 6 steps →
P0351: The power‑train control module (PCM) has detected abnormal voltage or resistance in the primary or secondary circuit of ignition coil A. In plain language, coil A is not receiving the correct voltage or ground, so cylinder 1 may misfire or fail to fire.
Discover what the P0351 trouble code means, how it affects engine performance, step‑by‑step DIY diagnostics, cost estimates, and make‑specific repair tips.
- Visual inspection of coil and wiring
- Read live data and freeze‑frame
- Measure primary resistance
- ...see all 7 steps →
P0352: The engine control module has detected a problem in the primary or secondary circuit of Ignition Coil B. This usually means the coil isn’t delivering the correct voltage to the spark plug, causing a misfire in the cylinder that coil serves.
Fix OBD-II code P0352: Ignition Coil B Primary/Secondary Circuit Malfunction. Step-by-step diagnosis and repair guide.
- Visual Inspection of Wiring and Connectors
- Read Freeze‑Frame Data and Live Misfire Count
- Test Primary Circuit Resistance of Coil B
- ...see all 7 steps →
P0353: The engine control module (ECM) has detected an abnormal voltage or resistance condition in the primary or secondary circuit of ignition coil C. In plain English, the coil that fires cylinder 3 isn’t sending the right spark signal, which can cause a misfire or rough running.
Fix OBD-II code P0353: Ignition Coil C Primary/Secondary Circuit Malfunction. Step-by-step diagnosis and repair guide.
- Read the diagnostic trouble code
P0354: The engine control module detects an abnormal voltage or resistance in the primary or secondary winding of ignition coil D. The fault usually points to the coil, its wiring, or the control circuit, and it can cause a misfire on the cylinder served by that coil.
Fix OBD‑II code P0354: Ignition Coil D Primary/Secondary Circuit Malfunction. Step‑by‑step diagnosis, repair guide, cost estimate, and safety tips.
- Visual inspection for loose or damaged parts
- Scan tool live data review
- Primary circuit continuity test
- ...see all 6 steps →
P0355: The PCM has detected an abnormal voltage or resistance in the primary or secondary circuit of ignition coil E. This usually means the coil, its wiring, or the control circuit isn’t delivering the spark needed for the cylinder that coil E serves.
Learn what the P0355 code means, why your engine misfires, and how to fix it. Quick DIY steps, cost breakdown, and make‑specific tips for Toyota, Honda,...
- Check for obvious issues
- Read live data and freeze‑frame
- Test coil E primary circuit resistance
- ...see all 7 steps →
P0356: The PCM has detected an abnormal voltage or resistance in the primary or secondary circuit of Ignition Coil F. This usually means the coil can't deliver a strong spark to its cylinder, leading to misfires and poor engine performance.
Learn what P0356 means, why it triggers misfires on Toyota, Honda, Ford, and Chevy, and get step‑by‑step DIY fixes with cost estimates, emissions impact,...
- Safety first
- Check for obvious issues
- Scan live data and freeze‑frame
- ...see all 7 steps →
P0357: The power‑train control module (PCM) has detected abnormal voltage or resistance in the primary or secondary circuit of ignition coil G. In plain language, the coil that fires cylinder G isn’t receiving a proper power or ground signal, so that cylinder may misfire or run weak.
Discover what P0357 means, how it affects performance, step‑by‑step DIY diagnostics, cost estimates, and model‑specific advice for Toyota, Honda, Ford, and...
- Quick Visual Scan
- Fuse & Power Check
- Live Data Review
- ...see all 7 steps →
P0358: The PCM has detected an abnormal voltage or resistance in the primary or secondary circuit of ignition coil H. In plain terms, the coil that fires cylinder 8 (or the coil pack for that cylinder) isn’t delivering the right spark, so the engine may misfire or run rough.
Learn what P0358 means, why it appears on Toyota, Honda, Ford and Chevy, and how to fix it fast. Get step‑by‑step DIY instructions, cost estimates and...
- Visual Scan for Loose/Corroded Connectors
- Check for Stored Trouble Codes & Freeze Frame Data
- Measure Primary Circuit Voltage at the Coil
- ...see all 6 steps →
P1345: P1345 tells the power‑train control module that the crankshaft and camshaft timing signals are out of sync. The engine’s computer can’t verify that the camshaft position matches the crankshaft position, which can cause misfires, rough idle, and reduced performance.
Learn what P1345 means, why it appears on Toyota, Honda, Ford, and Chevy, and get a step‑by‑step DIY fix with cost estimates, emissions impact, and safety tips.
- Check for Loose or Corroded Connectors
- Read Live Data for CKP and CMP
- Test Sensor Voltage
- ...see all 5 steps →
P2647: The P2647 code tells the engine control module that the oil‑pressure switch on the VTEC rocker arm for bank 1 is reporting a voltage that is higher than normal. In plain English, the sensor thinks oil pressure is too high or the circuit is shorted, prompting the PCM to limit VTEC operation.
Learn what P2647 means, why it appears on Toyota, Honda, Ford, and Chevy models, and how to diagnose and repair it—quick steps, cost estimates, and driving...
- Visual inspection of wiring and connector
- Check for obvious sensor faults
- Live data scan for oil‑pressure switch voltage
- ...see all 6 steps →
SYMPTOM-ROUGH-IDLE: The engine control module has detected irregular engine speed when the throttle is closed. In plain English, the computer sees the engine shaking or vibrating at idle and logs SYMPTOM‑ROUGH‑IDLE to warn you that something is upsetting the smooth running of the engine.
Fix OBD-II code SYMPTOM-ROUGH-IDLE: Car rough idle — causes, diagnosis, and fixes. Step‑by‑step guide with safety tips, cost estimates, and vehicle‑specific...
- Visual Inspection & Loose Connections
- Check for Stored Trouble Codes
- Inspect the Ignition System
- ...see all 8 steps →
SYMPTOM-WONT-START: The SYMPTOM-WONT-START code appears when the powertrain control module detects that the engine fails to crank and only a rapid clicking sound is heard. This usually points to a weak or dead battery, a faulty starter motor, or a broken starter circuit.
Fix OBD-II code SYMPTOM-WONT-START: Car won't start — clicking noise, no crank troubleshooting. Step-by-step diagnosis and repair guide.
- Read the diagnostic trouble code
Understanding Powertrain Ignition Codes
Powertrain Ignition diagnostic trouble codes are set by your vehicle's onboard computer (ECU/PCM) when it detects a problem in the ignition system. Here's what you need to know:
- How codes are triggered: Sensors monitor ignition performance. When readings fall outside expected ranges, the ECU stores a DTC and illuminates the check engine light.
- Freeze frame data: When a code is set, the ECU also records engine conditions at that moment. This data helps pinpoint the exact cause.
- Pending vs. confirmed: A code becomes "confirmed" after multiple drive cycles with the same fault. Pending codes may clear on their own.
Tools You'll Need for Diagnosis
- OBD-II scanner — Essential for reading and clearing codes. A basic scanner works for most codes.
- Digital multimeter — For testing sensor voltages, resistance, and continuity.
- Repair manual — Vehicle-specific wiring diagrams and specifications.
- Safety equipment — Gloves, safety glasses, jack stands for under-vehicle work.
When to See a Mechanic
While many ignition codes can be diagnosed at home, see a professional if:
- The code is critical severity — driving may cause further damage
- Multiple related codes are present — suggests a deeper systemic issue
- You don't have the tools or experience for the required diagnostic steps
- The repair involves fuel system, exhaust, or catalytic converter work