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P1399 Code: symptoms & diagnose




The p1399 code is a diagnostic trouble code (DTC) that indicates a problem with the electronic control module (ECM) or the powertrain control module (PCM). This code is specific to Honda and Acura vehicles.

When this code appears, it means that there is a random misfire detected in one or more cylinders. It could be caused by various factors such as fuel system issues, faulty ignition components, vacuum leaks, or even damaged engine components.

It’s important to note that while the p1399 code may seem like a minor issue, it can lead to serious engine problems if left unattended. The misfiring of one cylinder can cause damage to other parts of the engine over time and eventually result in costly repairs.

If you notice your check engine light illuminating and suspect an issue with your vehicle’s performance or fuel efficiency, it’s best to have it checked by a certified mechanic who can diagnose and fix any underlying issues causing the p1399 error code.

What is the P1399 code?

The P1399 code is a diagnostic trouble code (DTC) that indicates a misfire in one or more cylinders of an engine. It can occur in both gasoline and diesel engines, and it is commonly found on Honda vehicles.

When the powertrain control module (PCM) detects a misfire, it will set the P1399 code and turn on the check engine light. The PCM uses various sensors to determine when a misfire has occurred, including crankshaft position sensors, camshaft position sensors, and knock sensors.

There are several reasons why a misfire may occur in an engine. Common causes include faulty spark plugs, ignition coils, fuel injectors, or oxygen sensors. Other potential causes include low fuel pressure, vacuum leaks, or mechanical issues such as worn piston rings or damaged valves.

If left untreated, a misfire can cause damage to other components of the engine over time. It can also lead to decreased performance and reduced fuel efficiency.

To diagnose and repair the P1399 code properly, it is important to use specialized equipment such as scan tools and oscilloscopes. A mechanic will typically start by checking for any visible signs of damage or wear on key components such as spark plugs or ignition coils. They may also perform tests using specialized equipment to measure parameters such as fuel pressure or cylinder compression.

In some cases, replacing faulty components may be enough to resolve the issue causing the P1399 code. However, if underlying mechanical issues are present within the engine itself – such as problems with piston rings – more extensive repairs may be necessary.

Overall, while experiencing an engine misfire can be frustrating for vehicle owners; diagnosing and repairing this issue promptly with professional assistance from qualified mechanics can help ensure that your vehicle continues running smoothly for years to come without further complications caused by undiagnosed issues related with p1399 codes.

Symptoms of the P1399 code

If your vehicle’s check engine light is on and you’ve received a diagnostic trouble code (DTC) of P1399, there are several symptoms that may be present. These symptoms can help you identify what may be causing the issue.

One common symptom is engine misfires. This means that one or more cylinders in your engine are not firing properly, which can cause rough idling, hesitation during acceleration, and overall poor performance.

Another symptom is reduced power output. If your vehicle feels sluggish or lacks power when accelerating or climbing hills, it could be due to the P1399 code.

You may also notice increased fuel consumption if this code is present. The computer in your vehicle may compensate for the misfire by adding more fuel to the affected cylinders, resulting in decreased gas mileage.

In addition to these symptoms, you may experience difficulty starting your vehicle if the P1399 code is present. This could manifest as prolonged cranking times or a failure to start altogether.

It’s important to note that while these symptoms can indicate an issue related to the P1399 code, they can also be caused by other problems with your vehicle. It’s always best to have a professional mechanic diagnose and repair any issues with your car for optimal safety and performance.

Causes of the P1399 code

The P1399 code is a generic powertrain trouble code that indicates a problem with the engine’s misfire detection system. This code can be triggered by various factors, including:

  • Faulty spark plugs: Worn or damaged spark plugs can cause misfires in the engine, leading to the P1399 code.
  • Failing ignition coils: Ignition coils are responsible for generating high voltage electricity to ignite fuel in each cylinder. If one or more ignition coils fail, it may result in misfires and trigger this error code.
  • Clogged fuel injectors: Fuel injectors spray fuel into the engine’s cylinders at precise intervals to keep them running smoothly. When these injectors become clogged or dirty, they may not work as efficiently causing misfires and triggering this error.
  • Air intake issues: The air intake system brings clean air into the engine for combustion. If there are any leaks or restrictions in this system, it can disrupt airflow and cause an imbalance of oxygen-to-fuel ratio resulting in misfires and triggering this error.
  • Faulty sensors: Various sensors like camshaft position sensor (CMP), crankshaft position sensor (CKP), mass airflow sensor (MAF) etc., play crucial roles in detecting problems within your vehicle’s systems. A faulty sensor can lead to incorrect readings which could ultimately lead to causes behind p1399 codes being triggered.

If you encounter a P1399 error on your vehicle’s dashboard display, then consult with professionals immediately as ignoring such issues could worsen them over time damaging other parts of your car too!

Solutions for the P1399 code

If your vehicle’s check engine light has illuminated and you have received a diagnostic trouble code (DTC) of P1399, it is important to address the issue promptly. Ignoring this error can lead to serious engine problems such as misfires or even complete failure. Here are some solutions that may help resolve the P1399 code:

    1. Replace spark plugs: Worn or damaged spark plugs can cause misfires, leading to a P1399 code. Replace all spark plugs with new ones recommended by your vehicle manufacturer.
    2. Check ignition coils: Faulty ignition coils can also cause misfires and trigger a P1399 code. Use an ohmmeter to test each coil and replace any that show signs of wear or damage.
    3. Clean throttle body: A dirty throttle body can disrupt airflow, causing rough idling and triggering the P1399 code. Clean the throttle body with throttle cleaner spray according to your vehicle manufacturer’s instructions.
    4. Check fuel injectors: Clogged or malfunctioning fuel injectors can cause misfires and trigger a P1399 code. Have them checked by a mechanic for proper function and cleaning if needed.
    5. Clean EGR valve: The exhaust gas recirculation (EGR) valve helps reduce emissions but if it becomes clogged with carbon deposits, it can cause rough idling and trigger the P1399 code. Clean the EGR valve thoroughly using appropriate cleaners as per your car manual.

Note: In addition to these solutions above, there may be other causes for this error which require more advanced equipment diagnosis like checking camshaft position sensors, engine timing and control modules. It is recommended to seek professional help if the above solutions do not solve the problem.

By following these steps, you can address the P1399 code in your vehicle and ensure that your engine runs smoothly with no further issues. Regular maintenance of your vehicle’s components is essential for optimal performance and longevity.

How to diagnose the P1399 code

If your vehicle’s check engine light is on and you’ve retrieved a P1399 code, it indicates that there is an issue with the Variable Valve Timing (VVT) system in your engine. This can be caused by a variety of factors, including faulty sensors, damaged wiring, or problems with the VVT solenoid.

To properly diagnose and fix the issue causing the P1399 code, you’ll need to follow these steps:

1. Check for other codes – While the P1399 code specifically relates to VVT issues, there may be other codes present that could give further insight into what’s causing the problem. Use an OBD-II scanner to read all stored codes in your vehicle’s computer.

2. Inspect wiring and connectors – Faulty connections or damaged wiring can cause communication issues between various sensors and components in your engine. Visually inspect all wires and connectors related to the VVT system for any signs of damage or corrosion.

3. Test VVT solenoid – The VVT solenoid controls oil flow through passages that adjust camshaft timing. If it fails or becomes clogged with debris, it can cause issues with variable valve timing. To test this component, use a multimeter to check resistance across its terminals.

4. Check camshaft position sensor – The camshaft position sensor monitors camshaft speed and position so that proper fuel injection timing occurs during combustion cycles; if this sensor fails then poor performance may result from incorrect fuel injection timings as well as acceleration problems because of misfires caused by spark plugs firing at wrong times due lack synchronization between crankshaft &camshafts positions . Verify its output signal using an oscilloscope.

5.Check crankshaft position sensor- This sensor detects rotation speed of crankshaft which allows ECU calculate ignition timings along with Cam Shaft Sensor readings mentioned above

6.Inspect oil pressure – The VVT system relies on adequate oil pressure to function properly. Low oil pressure due to a clogged filter, worn pump or bad sensor may cause the engine light to come on and trigger the P1399 code.

7.Check timing chain/belt – If your vehicle has a timing belt or chain that drives the camshaft, it could be stretched or broken. This would prevent proper operation of the VVT system and could also cause other issues with engine performance.

By following these steps, you should be able to diagnose what’s causing your vehicle’s P1399 code and take appropriate action to fix it. If you’re unsure about any of these procedures or lack experience working on engines, it’s best to consult a professional mechanic for assistance.

How to fix the P1399 code

If you have encountered the P1399 code in your vehicle, it is an indication that there is a misfire detected in one or more cylinders. This can lead to poor engine performance and even damage if left unchecked. Here are some steps you can take to fix the P1399 code.

1. Check for other codes: Before proceeding with any repairs, check if there are any other codes present in your vehicle’s computer system. Other codes may indicate issues that need to be addressed before tackling the P1399 code.

2. Inspect spark plugs and ignition coils: The most common cause of a misfire is faulty spark plugs or ignition coils. Inspect these components for signs of wear or damage and replace as necessary.

3. Check fuel injectors: A clogged or malfunctioning fuel injector can also cause a misfire. Use a fuel injector cleaner or have them professionally cleaned if needed.

4. Examine vacuum lines: Leaking vacuum lines can disrupt air flow, causing a misfire in one or more cylinders.

5. Test compression levels: Low compression levels can also result in a misfire, so it’s important to test each cylinder’s compression level using a compression tester tool.

6. Replace oxygen sensors: Faulty oxygen sensors can cause irregularities in air/fuel ratios, leading to misfires and other issues with engine performance.

7. Clean throttle body: A dirty throttle body could affect airflow into the engine, resulting in poor combustion and ultimately causing a misfire.

8.Check wiring harnesses – Wiring harnesses connecting different parts of your car’s electrical system may become frayed over time which results into an electrical short circuit which might trigger this error code

By following these steps, you should be able to diagnose and repair the issue causing the P1399 code in your vehicle effectively!


In conclusion, the P1399 code is a generic OBD-II trouble code that indicates a misfire has been detected in multiple cylinders. This code can be caused by various factors such as faulty spark plugs, ignition coils, fuel injectors, or even low fuel pressure.

To diagnose and fix the problem associated with the P1399 code, it is important to perform a thorough inspection of all components related to the engine’s ignition system. The use of diagnostic tools such as an OBD-II scanner can help pinpoint the exact source of the issue.

Once identified, repairs should be carried out immediately to prevent further damage to other engine components. Regular maintenance practices such as replacing worn-out spark plugs and performing regular oil changes can also go a long way in preventing future occurrences of this issue.

It is worth noting that while some drivers may choose to ignore this warning light or attempt DIY repairs without professional assistance, doing so could result in costly engine damage or even compromise safety on the road. Therefore, it is highly recommended to seek professional assistance from qualified mechanics when dealing with any issues related to your vehicle’s performance.

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