AutoCodes – Acura – P0305 Acura

P0305 Acura Code - No. 5 Cylinder Misfire Detected

Quick Answer

The crankshaft vibrates slightly when each cylinder fires. Common causes include Valve adjustment, Faulty spark plug #5, Faulty ignition coil #5. 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: P0305 Acura indicates No. 5 Cylinder Misfire Detected.
Common causes: Common causes include Valve adjustment, Faulty spark plug #5, Faulty ignition coil #5.
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 24,680

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 Aug 16, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0305 Acura Description

The crankshaft vibrates slightly when each cylinder fires. If a misfire occurs, the crankshaft rotation speed changes rapidly. The Powertrain Control Module (PCM) monitors the crankshaft rotation speed based on the output pulses from the Crankshaft Position (CKP) Sensor. By monitoring changes in the crankshaft rotation speed, the PCM counts the number of misfires and determines which cylinder is misfiring. If a misfire is detected, a Diagnostic Trouble Code (DTC) is stored.
There are two types of misfire detection: Type 1: When the number of misfires per 200 engine revolutions reaches the level that can damage the three-way catalyst (TWC), a DTC is stored and the MIL blinks. Type 2: When the number of misfires per 1,000 engine revolutions reaches the level that affects exhaust emissions but is not severe enough to immediately damage the catalyst, a DTC is stored, and the MIL comes on.

OBDII Code P0305 Acura - No. 5 Cylinder Misfire Detected - AutoCodes.com — P0305 Acura Code - No. 5 Cylinder Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0305 Acura?

Valve adjustment
Faulty spark plug #5
Faulty ignition coil #5
Clogged or faulty fuel injector #5
Intake air leak
Insufficient cylinder #5 compression
Incorrect fuel pressure

How to Fix the DTC P0305 Acura?

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 does this mean?

Code Tech Notes

The P0305 code means that cylinder #5 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder #5. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0305 Acura 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 P0305 Acura Code

1. What are the common symptoms of OBDII code P0305 on an Acura?

A misfire in the No. 5 cylinder can cause rough idling, loss of power, engine vibrations, and in severe cases, potential engine stalling.

2. What are the typical causes of a No. 5 cylinder misfire in an Acura?

Potential causes include faulty ignition coils, spark plugs, fuel injectors, vacuum leaks, low compression, or issues with the engine's timing.

3. How can I diagnose the No. 5 cylinder misfire on my Acura?

Diagnosis involves using an OBDII scanner to retrieve the specific code (P0305), conducting a visual inspection of ignition components, performing a compression test, and potentially using a multimeter to check for electrical issues.

4. Can a dirty fuel injector cause a No. 5 cylinder misfire in an Acura?

Yes, a dirty or clogged fuel injector can disrupt the proper fuel delivery to the cylinder, leading to a misfire. Regular maintenance and using fuel system cleaners can help prevent this issue.

5. Is it safe to drive with a P0305 code on an Acura experiencing a No. 5 cylinder misfire?

Continuing to drive with a misfire can potentially cause damage to the catalytic converter and other engine components. It is recommended to address the issue promptly to prevent further damage.

6. How can I repair a No. 5 cylinder misfire on my Acura?

Repair options may include replacing faulty ignition components, spark plugs, fuel injectors, addressing vacuum leaks, checking and adjusting the engine's timing, or performing a cylinder compression test.

7. Can a bad spark plug cause a P0305 code on an Acura?

Yes, a worn-out or faulty spark plug in the No. 5 cylinder can lead to misfires and trigger the P0305 trouble code. Regularly replacing spark plugs as part of maintenance can prevent this issue.

8. Will resetting the OBDII code temporarily fix a No. 5 cylinder misfire on an Acura?

Resetting the code may temporarily eliminate the warning light, but it will not solve the underlying issue causing the misfire. It is essential to diagnose and address the root cause of the problem.

9. How important is it to fix a No. 5 cylinder misfire on my Acura promptly?

Promptly addressing a misfire issue is crucial to prevent further damage to the engine, ensure optimal performance, fuel efficiency, and reduce the risk of costly repairs down the line.

10. Can extreme weather conditions contribute to a No. 5 cylinder misfire in an Acura?

Extreme weather conditions, such as very cold or hot temperatures, can sometimes exacerbate existing issues like faulty ignition components or fuel delivery problems, leading to a misfire in the No. 5 cylinder.