P0303 Lexus Code - Cylinder 3 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 #3, Faulty ignition coil #3. 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
- P0303 Lexus indicates Cylinder 3 Misfire Detected.
- Common causes
- Common causes include Intake air leak, Faulty spark plug #3, Faulty ignition coil #3.
- 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.
Code P0303 Lexus Description
What are the Possible Causes of the DTC P0303 Lexus?
- Intake air leak
- Faulty spark plug #3
- Faulty ignition coil #3
- Clogged or faulty fuel injector #3
- Fuel injectors #3 harness is open or shorted
- Fuel Injectors #3 circuit poor electrical connection
- Ignition coils #3 harness is open or shorted
- Ignition coils #3 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 P0303 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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0303 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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Frequently Asked Questions about P0303 Lexus Code
1. What are the common symptoms of OBDII code P0303 (Cylinder 3 Misfire Detected) in a Lexus?
- Common symptoms include rough idling, engine hesitation, loss of power, increased fuel consumption, and potential engine vibrations.
2. What are the possible causes of a Cylinder 3 misfire in a Lexus triggering code P0303?
- Potential causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the engine control module.
3. How can I diagnose the specific cause of the Cylinder 3 misfire in my Lexus?
- Diagnose by checking the spark plug and ignition coil for Cylinder 3, performing a compression test, inspecting the fuel injector, and scanning for any other related trouble codes.
4. Can a dirty or clogged fuel injector cause a Cylinder 3 misfire in a Lexus?
- Yes, a dirty or clogged fuel injector can disrupt fuel delivery to Cylinder 3, leading to a misfire condition and triggering code P0303.
5. What is the recommended repair approach for resolving OBDII code P0303 in a Lexus due to a Cylinder 3 misfire?
- Repair steps may include replacing spark plugs, ignition coils, or fuel injectors for Cylinder 3, addressing any vacuum leaks, conducting a compression test, and resetting the fault code.
6. Is it safe to continue driving my Lexus with OBDII code P0303 related to a Cylinder 3 misfire?
- It is not recommended to drive your Lexus with a misfire condition as it can lead to further damage to the engine or emissions components. It's best to address the issue promptly.
7. Can a faulty engine control module (ECM) be a potential cause of OBDII code P0303 in a Lexus?
- Yes, a malfunctioning ECM can sometimes incorrectly signal the ignition system, leading to a misfire in Cylinder 3 and triggering the OBDII code P0303.
8. How important is it to address OBDII code P0303 promptly in a Lexus?
- Promptly addressing code P0303 is crucial to prevent potential damage to the catalytic converter, other engine components, and to maintain optimal engine performance and fuel efficiency.
9. After repairing the issue causing OBDII code P0303, how can I reset the check engine light in my Lexus?
- To reset the check engine light, you can use an OBDII scanner to clear the fault code after the repair has been completed successfully.
10. Are there any maintenance tips to prevent Cylinder 3 misfires triggering code P0303 in a Lexus?
- Regular maintenance such as timely spark plug replacements, using high-quality fuel, and addressing any engine performance issues promptly can help prevent Cylinder 3 misfires and OBDII code P0303 in a Lexus.
Discuss the causes and fixes for P0303 Lexus OBDII Code
-
I get the P0303 code just as the engine starts, most of the time.
As the engine starts i feel a very short stumble and the engine light blinks, then shows constantly on but after about 3 or 4 seconds the engine smooths out and no blinking again until i restart. The engine will then drive fine with no cylinder stumble until restart.
(I already changed the coil.) -
What model and year is your vehicle? have you notice any excessive smoke during cold start? is the smoke black or white?
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i get a code of po300 and po303 on lexus gx470 and i discover that after long parking about 2 to 3 hours the vehicle do high starting and bring out black smoke before starting
-
Sounds like the #3 injector is leaking. You should remove the spark plug and inspect the plug.
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