AutoCodes – Scion – P0303 2006 Scion xB

P0303 2006 Scion xB Code - Cylinder 3 Misfire Detected

Quick Answer

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Common causes include Faulty spark plug (s), Faulty ignition coil (s), Clogged or faulty fuel injector (s). 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 2006 Scion xB indicates Cylinder 3 Misfire Detected.
Common causes: Common causes include Faulty spark plug (s), Faulty ignition coil (s), Clogged or faulty fuel injector (s).
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 5,276

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0303 2006 Scion xB Description

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emission levels. High concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the TWC. To prevent these increases in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP 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 exceeds the threshold levels, and could cause emission deterioration, the ECM illuminates the MIL and sets a DTC.

OBDII Code P0303 2006 Scion xB - Cylinder 3 Misfire Detected - AutoCodes.com — P0303 2006 Scion xB Code - Cylinder 3 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0303 2006 Scion xB?

Faulty spark plug (s)
Faulty ignition coil (s)
Clogged or faulty fuel injector (s)
Intake air leak
Fuel injectors harness is open or shorted
Fuel Injectors circuit poor electrical connection
Ignition coils harness is open or shorted
Ignition coils circuit poor electrical connection
Insufficient cylinders compression
Incorrect fuel pressure
Mass air flow meter
Engine coolant temperature sensor
Valve clearance
Valve timing
ECM

How to Fix the DTC P0303 2006 Scion xB?

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 P0303 code means that the cylinder 3 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 3. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes"

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 2006 Scion xB 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 P0303 2006 Scion xB Code

1. What are the common symptoms of OBDII code P0303 (Cylinder 3 Misfire Detected) in a 2006 Scion xB?

- Common symptoms include rough idling, loss of power, engine vibration, and potential increase in fuel consumption.

2. What are some possible causes of OBDII code P0303 in a 2006 Scion xB?

- Potential causes include faulty spark plugs, a failing ignition coil, clogged fuel injector, vacuum leak, or low compression in cylinder 3.

3. How can I diagnose the cause of OBDII code P0303 in my 2006 Scion xB?

- Diagnose by checking spark plugs, inspecting the ignition coil, testing the fuel injector, conducting a compression test, and looking for vacuum leaks.

4. Can I still drive my 2006 Scion xB with OBDII code P0303?

- It is not recommended to drive the vehicle with a misfire as it can cause damage to the catalytic converter. Have the issue diagnosed and repaired promptly.

5. How can I repair OBDII code P0303 in my 2006 Scion xB?

- Repair may involve replacing spark plugs, ignition coil, fuel injector, fixing vacuum leaks, or addressing any compression issues in cylinder 3.

6. Is it necessary to reset the OBDII code P0303 after repairing my 2006 Scion xB?

- It is recommended to clear the code using an OBDII scanner after the repair to see if the issue has been resolved and to prevent potential future problems.

7. What should I do if OBDII code P0303 in my 2006 Scion xB keeps coming back after repairs?

- If the code persists, recheck the components replaced, inspect for any new issues, and consider seeking professional diagnostic assistance.

8. Can bad gasoline cause OBDII code P0303 in a 2006 Scion xB?

- While bad gasoline can contribute to misfires, it is not a common cause of a specific cylinder misfire like code P0303. Focus on checking ignition and fuel system components.

9. Are there any maintenance tips to prevent OBDII code P0303 in a 2006 Scion xB?

- Regularly maintain your vehicle by following the manufacturer's recommended service schedule, including changing spark plugs and inspecting ignition components.

10. How serious is OBDII code P0303 in a 2006 Scion xB?

- Ignoring a misfire can lead to engine damage and increased emissions. It is recommended to address the issue promptly to prevent further complications.