AutoCodes – Lexus – P0302 Lexus

P0302 Lexus Code - Cylinder 2 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 #2, Faulty ignition coil #2. 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: P0302 Lexus indicates Cylinder 2 Misfire Detected.
Common causes: Common causes include Intake air leak, Faulty spark plug #2, Faulty ignition coil #2.
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 43,154

How popular is this code, among other codes? Medium

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
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0302 Lexus 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 P0302 Lexus - Cylinder 2 Misfire Detected - AutoCodes.com — P0302 Lexus Code - Cylinder 2 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0302 Lexus?

Intake air leak
Faulty spark plug #2
Faulty ignition coil #2
Clogged or faulty fuel injector #2
Fuel injectors #2 harness is open or shorted
Fuel Injectors #2 circuit poor electrical connection
Ignition coils #2 harness is open or shorted
Ignition coils #2 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 P0302 Lexus?

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 P0302 code means that cylinder #2 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 #2. 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 P0302 Lexus 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 P0302 Lexus Code

1. What are the common symptoms of OBDII code P0302 in a Lexus indicating a cylinder 2 misfire?

- Common symptoms include engine vibration, rough idling, loss of power, and potential fuel smell from the exhaust.

2. What are some possible causes of a cylinder 2 misfire in a Lexus triggering the P0302 code?

- Possible causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the engine's computer.

3. How can I diagnose the specific cause of the cylinder 2 misfire in my Lexus with the P0302 code?

- Diagnose by checking the spark plugs, ignition coils, and fuel injectors for any signs of wear or damage. Perform a compression test on cylinder 2 and inspect for vacuum leaks.

4. Will driving my Lexus with an active P0302 code causing a cylinder 2 misfire damage the engine?

- Continuing to drive with a misfire can potentially cause damage to the catalytic converter, O2 sensors, or other engine components. It is recommended to address the issue promptly.

5. Can a dirty or clogged fuel injector be a common reason for the P0302 code in a Lexus?

- Yes, a dirty or clogged fuel injector can disrupt the fuel delivery to cylinder 2, leading to a misfire and triggering the P0302 code.

6. Is it recommended to clear the P0302 code in my Lexus after fixing the cylinder 2 misfire issue?

- Yes, after addressing the underlying cause of the misfire, it is recommended to clear the code to see if it returns. This can help verify if the repair was successful.

7. Are there any maintenance tips to prevent the recurrence of the P0302 code in my Lexus?

- Regular maintenance, such as changing spark plugs and inspecting ignition components, can help prevent cylinder misfires. Using high-quality fuel and keeping up with scheduled services is also beneficial.

8. Can extreme weather conditions affect the likelihood of triggering the P0302 code in a Lexus?

- Extreme weather conditions, such as very cold or hot temperatures, can sometimes exacerbate existing issues leading to a cylinder misfire. Ensuring proper engine cooling and insulation can help mitigate these effects.

9. Should I seek professional help to diagnose and repair the P0302 code in my Lexus, or can I attempt to fix it myself?

- While some DIY enthusiasts may be able to address simpler causes like changing spark plugs, more complex issues may require professional diagnostic tools and expertise to properly diagnose and repair.

10. How long can I safely drive my Lexus with the P0302 code before getting it fixed?

- It is not recommended to drive your Lexus with an active misfire code, as prolonged driving can lead to further damage. It is best to address the issue as soon as possible to prevent potential engine damage.

Discuss the causes and fixes for P0302 Lexus OBDII Code

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Quantas Gaines
Date: February 25, 2018 at 2:15 am

I've been getting code P0302 on my 2001 Rx 300. I've replaced plugs and coil. And I'm still getting the same code but the miss isn't as bad. Does anyone have any ideas

Reply to Comment
OBDIITech
Date: February 26, 2018 at 4:15 pm

Have you checked the spark plugs? you could try swapping the plug with another cylinder plug to see if the code follows the plug. If you get the same code, then the next step is to perform a compression test.

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