This page contains links to third parties, if you click through those links we may receive a commission at no extra cost to you.

Engine Fault Code P0312

Cylinder 12 Misfire Detected

Care Engine Code Reader
The Engine Fault Code P0312 means that there is a misfire detected in cylinder 12 of your engine. A misfire occurs when the fuel-air mixture in the cylinder fails to ignite properly, which can lead to poor engine performance, increased emissions, and potential damage over time.

While P0312 is a standard code, the specifics can vary by manufacturer. Here are some alternative meanings or related codes that might be found in different vehicles:

1. P0300 – Random/Multiple Cylinder Misfire Detected: This code indicates misfires in multiple cylinders, which can sometimes include cylinder 12.

2. P0301-P0306 – These codes indicate misfires in specific cylinders (1-6). For example, P0301 is for cylinder 1, P0302 is for cylinder 2, and so on.

3. Manufacturer-Specific Codes: Some manufacturers may have specific codes that relate to misfires or engine performance issues. For example:
– P0308 might indicate a misfire in cylinder 8 in some V8 engines.
– P0311 could indicate a misfire detected in cylinder 11 for vehicles with a higher cylinder count.

4. Symptoms: Depending on the vehicle, you might also see symptoms like rough idling, loss of power, or increased fuel consumption when this code is triggered.

5. Possible Causes: The causes of a P0312 code can include issues like faulty spark plugs, ignition coils, fuel delivery problems, or mechanical issues within the engine.

If you`re seeing this code, it`s best to diagnose the issue thoroughly. Start by checking the spark plugs and ignition coils for cylinder 12, and consider looking at the fuel injectors and engine compression as well.
The Engine Fault Code P0312 indicates a misfire detected in cylinder 12. This issue can arise from several factors, and while the basic causes are similar across different manufacturers, there can be specific nuances depending on the vehicle. Here are some common causes:

Common Causes of P0312:

1. Ignition System Issues:
– Faulty Spark Plug: A worn or damaged spark plug can lead to misfires.
– Bad Ignition Coil: If the ignition coil for cylinder 12 is failing, it won`t provide the necessary spark.
– Wiring Problems: Damaged or corroded wiring can disrupt the spark.

2. Fuel Delivery Problems:
– Clogged Fuel Injector: A blocked injector can prevent the right amount of fuel from reaching the cylinder.
– Fuel Pump Issues: If the fuel pump isn`t delivering enough fuel, it can cause a misfire.

3. Air Intake Issues:
– Vacuum Leaks: A leak in the intake system can alter the air-fuel mixture.
– Faulty Mass Air Flow (MAF) Sensor: If the MAF sensor is malfunctioning, it can send incorrect data to the engine control unit (ECU).

4. Engine Mechanical Issues:
– Low Compression: Problems like worn piston rings or a blown head gasket can lead to low compression in the cylinder.
– Timing Issues: If the timing belt or chain is off, it can affect engine performance.

5. Sensor Problems:
– Faulty Crankshaft or Camshaft Position Sensor: These sensors are crucial for timing and can cause misfires if they fail.

Manufacturer-Specific Considerations:

Porsche: Misfires can sometimes be linked to the Direct Fuel Injection system. Check for carbon buildup on the intake valves.

Mini: Older models may have issues with the ignition system due to their unique coil design. Check for software updates that might address misfire issues.

Mercedes-Benz: Look for issues related to the M274 or M276 engines, which can have specific ignition coil problems.

Audi: Some Audis use a twin-charging system (supercharger and turbocharger), which can complicate misfire diagnosis. Check for boost leaks.

Jaguar: Jaguars with V8 engines may have specific issues with the ignition system or fuel delivery that can cause misfires.

Land Rover: For models with the 3.0L supercharged V6, check for issues with the supercharger bypass valve, which can affect performance.



If you encounter code P0312, its essential to perform a thorough diagnosis. Start by checking the ignition system, fuel delivery, and air intake. Depending on the make and model of your vehicle, specific components may need more attention. Always refer to the vehicles service manual for detailed troubleshooting steps.
Fixing the Engine Fault Code P0312, which indicates a misfire detected in cylinder 12, can vary based on the vehicle`s make and model. Below are general steps and manufacturer-specific considerations for European cars like Porsche, Mini, Mercedes, Audi, Jaguar, and Land Rover.

General Steps to Diagnose and Fix P0312:

1. Check Spark Plug:
– Remove the spark plug from cylinder 12. Look for signs of wear, damage, or carbon buildup. Replace if necessary.

2. Inspect Ignition Coil:
– Test the ignition coil for cylinder 12. If it`s faulty, replace it. You can swap it with another cylinder to see if the misfire moves.

3. Fuel Injector Test:
– Check the fuel injector for cylinder 12 to ensure it`s working properly. You can use a multimeter to test the resistance or listen for clicking sounds.

4. Compression Test:
– Conduct a compression test on cylinder 12. Low compression can indicate a more serious issue like a blown head gasket or valve problems.

5. Check for Vacuum Leaks:
– Inspect hoses and intake manifold gaskets for leaks that could affect cylinder performance.

6. ECU Software Update:
– Sometimes, a software update from the manufacturer can resolve misfire issues. Check with a dealer or service center.

7. Examine Wiring and Connectors:
– Look for damaged wiring or loose connectors related to the ignition coil and fuel injector.

Manufacturer-Specific Considerations:

Porsche:
– Check for Faulty DME (Digital Motor Electronics): If other cylinders are misfiring, the DME may need calibration or replacement.

Mini:
– Inspect the Vanos System: Issues with the Vanos can affect timing and cause misfires. Check for faults in the system.

Mercedes:
– Review the MAF Sensor: A dirty or faulty Mass Air Flow sensor can lead to incorrect air-fuel mixture, causing misfires.

Audi:
– Look for Carbon Build-Up: Audi engines, especially older models, can suffer from carbon build-up on intake valves. Consider a cleaning service.

Jaguar:
– Check for Faulty Camshaft Timing: Misalignment can lead to misfires. Inspect the timing chain/belt and tensioners.

Land Rover:
– Inspect the Fuel System: Land Rovers can have issues with fuel pumps or filters that can affect injector performance.

Final Steps:
After making repairs or replacements, clear the fault codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns. If it does, further diagnosis may be needed.

Always consult the vehicle`s service manual for specific procedures and specifications. If you`re unsure or uncomfortable with any steps, it`s best to seek professional help.
Driving with a P0312 code, which indicates a misfire in cylinder 12, is generally not recommended. Here`s why:

1. Engine Damage: Continuing to drive with a misfire can lead to more serious engine damage over time. The unburned fuel can wash down the cylinder walls and damage the engine.

2. Fuel Efficiency: A misfire can significantly reduce fuel efficiency, leading to higher gas costs.

3. Exhaust Damage: Misfires can cause unburned fuel to enter the exhaust system, potentially damaging the catalytic converter, which is an expensive repair.

4. Safety Risks: Depending on the severity of the misfire, the car may lose power or stall, which can be dangerous, especially in traffic.

Manufacturer-Specific Considerations

Porsche: Porsche engines are finely tuned, and a misfire can lead to performance issues. It`s best to address it quickly to avoid costly repairs.

Mini: Mini vehicles can be sensitive to misfires due to their turbocharged engines. Ignoring the code could lead to more extensive repairs.

Mercedes: Mercedes vehicles often have advanced engine management systems that can compensate for some misfires, but it`s still not safe to drive for long periods.

Audi: Like Mercedes, Audi engines have sophisticated systems. However, a misfire can trigger other issues, so it`s advisable to fix it promptly.

Jaguar: Jaguars are known for their luxury performance. A misfire can affect handling and comfort, and it`s best to get it checked out soon.

Land Rover: Land Rovers are built for rugged terrain, but a misfire can impact their reliability. It`s best to address the issue to maintain performance.

Conclusion

While some vehicles might handle a misfire for a short time, it`s not safe to drive long-term with a P0312 code. Always have it diagnosed and repaired as soon as possible to avoid further damage and ensure your safety.

OBD Codes Explained

Engine Codes

P is for PowerTrain - Engine and Transmission.

P0 Indicates Generic Powertrain Codes

P0 Codes indicate problems with the powertrain and are common for all vehicles using the OBD-II Standard.

P1 Enhanced Manufacturer Specific Codes

P1 Codes are specific to manufacturers.

Sub-System

The 3rd Digit indicates the Sub-System

1 – Emission Management

2 – Injector Circuit

3 – Ignition

4 – Emission Control

5 – Vehicle Speed and Idle

6 – Computer and Output

7 – Transmission

8 – Transmission

9 – Reserved

0 – Reserved

0
    0
    Your Cart
    Your cart is emptyReturn to Shop

    Need parts advice?

    Tell us what you need and we will be in touch shortly.

    Contact Information
    Vehicle Information