AutoCodes – BMW – P1346 BMW

P1346 BMW Code - Misfire During Start Cylinder 3

Quick Answer

As part of the CARB/OBD regulations, the Engine Control Module (ECM) must determine if a misfire is occurring and also identify the specific cylinder(s) and the severity of the misfire event and whether it is emissions relevant or catalyst damaging. Common causes include Faulty Spark Plug, Faulty Ignition Coil, Intake vacuum leak. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1346 BMW indicates Misfire During Start Cylinder 3.
Common causes: Common causes include Faulty Spark Plug, Faulty Ignition Coil, Intake vacuum leak.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 24,469

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 17, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1346 BMW Description

As part of the CARB/OBD regulations, the Engine Control Module (ECM) must determine if a misfire is occurring and also identify the specific cylinder(s) and the severity of the misfire event and whether it is emissions relevant or catalyst damaging. In order to accomplish these tasks, the control module monitors the crankshaft for acceleration losses during firing segments of each cylinder based on firing order.
The misfire/engine roughness calculation is derived from the differences in the period duration (T) of individual increment gear segments. Each segment period consists of an angular range of 120Â° crank angle that starts 78Â° before Top Dead Center (TDC).
If the expected period duration is greater than the permissible value a misfire fault for the particular cylinder is stored in the fault memory of the ECM. Depending on the level of misfire rate measured the control unit will illuminate the "Service Engine Soon" light, may cutoff fuel to the particular cylinder and may switch lambda operation to open-loop. All misfire faults are weighted to determine if the misfire is emissions relevant or catalyst damaging.

OBDII Code P1346 BMW - Misfire During Start Cylinder 3 - AutoCodes.com — P1346 BMW Code - Misfire During Start Cylinder 3

What does this mean?

What are the Possible Causes of the DTC P1346 BMW?

Faulty Spark Plug
Faulty Ignition Coil
Intake vacuum leak
Faulty Camshaft Position Sensor
Ignition Coil harness is open or shorted
Ignition Coil circuit poor electrical connection

How to Fix the DTC P1346 BMW?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1346 BMW code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1346 BMW Code

1. What are the common symptoms of OBDII code P1346 in a BMW related to misfire during start cylinder 3?

- Common symptoms include rough idle, engine misfires, decreased performance, and possibly an illuminated check engine light.

2. What are the possible causes of OBDII code P1346 in a BMW indicating misfire during start cylinder 3?

- Potential causes can include faulty ignition coils, spark plugs, fuel injectors, wiring issues, vacuum leaks, or a problem with the engine control module.

3. How can I diagnose the source of OBDII code P1346 in a BMW for cylinder 3 misfire during start?

- Diagnosis typically involves performing a thorough inspection of the ignition system components, checking for vacuum leaks, testing fuel injectors, and possibly using a scan tool to monitor live data.

4. Is it safe to continue driving my BMW with OBDII code P1346 indicating misfire during start cylinder 3?

- It is not recommended to drive the vehicle extensively with a misfire issue as it can lead to further damage to the engine and emissions system. It's best to address the problem promptly.

5. Can I repair OBDII code P1346 in a BMW related to misfire during start cylinder 3 myself?

- Depending on your skill level and access to tools, you may be able to address some causes of the misfire, such as replacing spark plugs or ignition coils. However, more complex issues may require professional diagnosis and repair.

6. How can I prevent OBDII code P1346 from reoccurring in my BMW after repairing the misfire issue?

- To prevent the code from reoccurring, it's important to perform regular maintenance on your BMW, including changing spark plugs at recommended intervals, using high-quality fuel, and addressing any engine-running issues promptly.

7. Are there any specific tips for addressing OBDII code P1346 in a BMW that may help with the repair process?

- One tip is to check the condition of the spark plugs and ignition coils for cylinder 3, as these components are often the culprits for misfire issues. Additionally, ensuring proper fuel and air delivery is crucial for optimal engine performance.

8. Should I reset the OBDII code P1346 in my BMW after repairing the misfire issue?

- It's recommended to clear the code using a scan tool after addressing the misfire problem. This will reset the check engine light and allow you to monitor if the issue has been successfully resolved.

9. How long does it typically take to repair OBDII code P1346 in a BMW related to misfire during start cylinder 3?

- The repair time can vary depending on the specific cause of the misfire. Simple fixes like replacing spark plugs may only take a short amount of time, while diagnosing and repairing more complex issues can take longer.

10. Can a BMW dealership or a qualified mechanic help me with diagnosing and repairing OBDII code P1346 related to misfire during start cylinder 3?

- Yes, experienced technicians at a BMW dealership or a reputable mechanic shop can assist in diagnosing and repairing the misfire issue indicated by OBDII code P1346. Their expertise and specialized tools can help ensure an accurate and effective repair.