AutoCodes – Toyota – P0307 Toyota

P0307 Toyota Code - Cylinder 7 Misfire Detected

Quick Answer

When the engine misfires, high concentrations of Hydrocarbons (HC) enter the exhaust gas. Common causes include Intake air leak, Faulty spark plug #7, Faulty ignition coil #7. 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: P0307 Toyota indicates Cylinder 7 Misfire Detected.
Common causes: Common causes include Intake air leak, Faulty spark plug #7, Faulty ignition coil #7.
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 11,381

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 25, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0307 Toyota Description

When the engine misfires, high concentrations of Hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the Engine Control Module (ECM) monitors the misfire count. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels and could cause emission control system performance deterioration, the ECM illuminates the MIL and stores a Diagnostic Trouble Code (DTC).

OBDII Code P0307 Toyota - Cylinder 7 Misfire Detected - AutoCodes.com — P0307 Toyota Code - Cylinder 7 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0307 Toyota?

Intake air leak
Faulty spark plug #7
Faulty ignition coil #7
Clogged or faulty fuel injector #7
Fuel injectors #7 harness is open or shorted
Fuel Injectors #7 circuit poor electrical connection
Ignition coils #7 harness is open or shorted
Ignition coils #7 circuit poor electrical connection
Incorrect Fuel pressure
Faulty Mass Air Flow (MAF) Sensor
Faulty Engine Control Module (ECM)
Faulty Engine Coolant Temperature (ECT) Sensor

How to Fix the DTC P0307 Toyota?

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 P0307 code means that cylinder #7 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 #7. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0307 Toyota 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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Need Help with the Code?

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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 P0307 Toyota Code

1. What are common symptoms of OBDII code P0307 in a Toyota indicating Cylinder 7 misfire?

Symptoms may include engine misfiring, rough idling, loss of power, increased fuel consumption, and potential engine vibrations.

2. What are the possible causes of a Cylinder 7 misfire in a Toyota triggering code P0307?

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

3. How can I diagnose the specific cause of a Cylinder 7 misfire in my Toyota with code P0307?

Performing a diagnostic scan, checking the spark plugs, inspecting the ignition coils, testing the fuel injectors, conducting a compression test, and looking for vacuum leaks can help pinpoint the exact issue.

4. Can driving with OBDII code P0307 on a Toyota lead to further damage?

Continuing to drive with a misfire in Cylinder 7 can potentially cause damage to the catalytic converter, oxygen sensors, or other engine components over time, so prompt repair is recommended.

5. Is it safe to continue driving my Toyota with OBDII code P0307 if the engine seems to be running normally?

Even if the engine appears to be running fine, it is still advisable to address the underlying cause of the Cylinder 7 misfire to prevent potential long-term damage and maintain optimal engine performance.

6. What are some general repair tips for fixing a Cylinder 7 misfire in a Toyota showing OBDII code P0307?

Consider replacing the spark plugs, ignition coils, or fuel injectors in Cylinder 7, checking and repairing any vacuum leaks, ensuring proper engine timing, and performing a thorough inspection of the ignition system.

7. Can a DIY enthusiast tackle the repair of a Cylinder 7 misfire with code P0307 in a Toyota?

Depending on their skill level and access to tools, a knowledgeable DIY enthusiast may be able to address certain causes of the misfire, such as replacing spark plugs or ignition coils, but more complex issues may require professional assistance.

8. How long does it typically take to repair a Cylinder 7 misfire triggering OBDII code P0307 in a Toyota?

The repair time can vary based on the specific cause of the misfire and the extent of the necessary repairs, but it may range from a few hours to a full day, especially if diagnostics are needed.

9. Should I reset the OBDII code P0307 in my Toyota after fixing the Cylinder 7 misfire issue?

After resolving the misfire problem causing code P0307, it is recommended to clear the code using an OBDII scanner to reset the Check Engine Light and ensure the repair was successful.

10. How can regular maintenance help prevent Cylinder 7 misfires in a Toyota and avoid OBDII code P0307?

Routine maintenance such as changing spark plugs, inspecting ignition components, replacing fuel filters, and keeping up with recommended service intervals can help prevent Cylinder 7 misfires and prolong the engine's health.