Scion Vehicle Care: Easy Guide to Reading & Clearing Fault Codes
SCION, known for its youthful appeal and quirky designs, prioritizes driver enjoyment and ease of ownership. But even the most reliable vehicles can encounter glitches. That’s where Diagnostic Trouble Codes (DTCs) come in. Over 60 warning lights could illuminate your dashboard; these include ABS, SRS, transmission temperature, oil pressure, battery charging, differential, traction control, and many more. That is why it is essential to know about check engine lights and error codes to retain your vehicle’s performance and safety.
The check engine light is a warning indicator that tells you that there is a problem with your vehicle’s engine or emissions system. When the check engine light comes on, it is important to have your vehicle scanned for fault codes. If you need to learn more about checking engine lights, we have an in-depth article that you can find here.
DTCs are like Morse codes from your Scion, revealing hidden issues that might hinder its optimal performance. These alphanumeric codes provide clues to underlying problems, empowering mechanics or DIY enthusiasts to diagnose and repair them efficiently. Understanding DTCs will help many people, especially vehicle owners, stay informed about their vehicle’s health and make informed decisions about its maintenance.
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How to Read and Clear Scion Fault Codes
- Gather the necessary tools: Equip yourself with a Professional-Grade OBD-II Scanner that is compatible with your Scion. Click Here for our Professional-Grade YOUCANIC Scanner

- Access the OBD-II Port: This port is usually found under the dashboard, near the steering column, the OBD-II port is the gateway to your car’s diagnostic information. Turn the ignition key to the “ON” position without starting the engine to make a connection with the vehicle’s computer. If your Scion has a START/STOP feature, press the button without pressing the brake pedal. Do not start the engine. If you are unsure of the OBD-II port of your vehicle, you can always check the car owner’s manual.

- Access the Diagnostic Menu: On the YOUCANIC scanner’s display, navigate to the “Diagnostic” or “Scan” menu. This menu allows you to access various diagnostic functions for your Scion.

- Select ‘SCION’ as the Vehicle Make: This ensures the scanner effectively communicates with the Scion On-Board Diagnostic system and effectively scans the fault codes.

- Select option for model selection: The scanner has various options for model selection, you can choose SmartVIN to detect your vehicle automatically. However, you choose Manual Selection if SmartVIN does not work as intended.

- Select the Specific Model and Chassis: After selecting the vehicle make, scroll through the available models and select the correct one for your Scion. Additionally, choose the corresponding chassis or body type to properly sync the scanner to your vehicle.

- Select Control Units: Once you have selected the model and chassis, the scanner will let you choose between “Quick scan” or “Control Modules”. Control Modules display a list of control units or modules in your vehicle. Examples include the engine control module (ECM), transmission control module (TCM), and ABS control module. Choose the specific module you want to diagnose. Otherwise, you can also opt to choose the “Quick Scan” to check everything.

- Interpret the Codes: Once the YOUCANIC scanner completes the code retrieval process, the displayed codes will provide information about specific issues detected by the control unit. Take note of these codes for further analysis and diagnosis. Each DTC consists of a letter and four numbers. The letter indicates the system affected, while the numbers describe the issue more specifically. Click here to learn more about fault codes.

- Erase Codes: After the problem has been repaired, return to the scanner’s menu and select the option to “Erase Codes” or “Clear Codes.” This action removes the stored fault codes from the control unit’s memory, indicating that the problem has been resolved. Please take note that you may or may not erase a code when the issue is not fixed.

NOTE: These pictures are just the demo of our YOUCANIC Scanner, it may or may not be the same but the procedure is the same.
To unravel the mysteries of these automotive enigmas, you’ll need a tool called the OBD-II scanner, or you’ll even need a professional-grade scanner for luxury brands. This handy device acts as a decoder, translating the cryptic codes into a language we can comprehend. In this section, we’ll delve into details of reading and erasing DTC/Fault codes of your Infiniti with models like QX50, QX55, QX60, QX30, Infiniti M, Infiniti QX, Infiniti G, and many more newer or older models. Once connected to your Infiniti’s diagnostic port, the scanner will display the Fault codes, typically a five-digit code. Click here to learn more about fault codes.
Is it okay to always check my DTCs?
Regularly scanning your Scion for DTCs is akin to giving your vehicle a check-up. It’s recommended to scan your car at least once a year, or more frequently if you notice any performance issues or warning lights illuminating.
Why do I need to scan my vehicle?
There are several reasons why you should scan your vehicle for fault codes:
- To identify the source of the problem. Fault codes can help you pinpoint the specific problem with your vehicle. This can save you time and money on repairs
- To prevent further damage. Ignoring fault codes can lead to further damage to your vehicle and it can be dangerous as well.
- It can improve fuel efficiency, and fixing problems that are causing fault codes can improve a vehicle’s fuel efficiency depending on the malfunctioned part.
- To pass emission testing in some states, you may be required to have your vehicle scanned for fault code before you can pass emission testing
You can check out one of our articles about what is the best OBD-II Scanner for DIY Enthusiasts here: Best OBD2 Scanner For DIY Auto Repair – YOUCANICBest OBD2 Scanner For DIY Auto Repair – YOUCANIC
Why can’t I clear the codes of my Scion?
Once you’ve identified the DTCs, you may be tempted to clear them, hoping to continue driving your Scion, and the problem magically disappears. While clearing the codes can temporarily remove the “Check Engine” light, it doesn’t address the underlying issue. It will always come back. Here are also some lists of why you cannot clear the codes of your Scion:
- Use a Professional-Grade Scanner: Ditch the generic scanner and upgrade to a professional-grade one like the YOUCANIC scanner. Generic scanners are like trying to open a Ferrari with a Ford key – it won’t work! YOUCANIC, on the other hand, is like the master key to your Scion’s diagnostics, unlocking hidden diagnostic powers and letting you clear codes that would otherwise remain stubborn and hidden.
- Underlying Issues: Before you go clearing fault codes, remember to address the underlying issue that triggered them in the first place. Clearing codes is like patching a leaky pipe without fixing the cracked valve – it’s just a temporary fix. The ‘check engine’ light will surely come back and haunt you.
- Continuous Fault Monitoring: Certain fault codes, like the SRS system, may be cleared by disconnecting the battery (like a reset). However, they will reappear even after clearing until the root cause is resolved. Think of it as a persistent reminder to fix the problem, not just mask it.
- Proper Clearing Procedure: To clear fault codes effectively, follow the correct steps outlined in your diagnostic scanner’s user manual. If you are unsure about the clearing procedure, consult a professional for guidance specific to your scanner and Scion model.
What happens when I ignore the fault codes?
It can lead to several problems, like further damage to your vehicle, because the issue causing the fault code may get worse and cause further damage.
Ignoring fault codes can lead to increased emissions, harming the environment.
Failure to pass emission testing could happen if you ignore fault codes; you may not be able to pass the emission testing in your state.
What do History, Current, and Stored DTCs do?
- History: These codes indicate past issues that have resolved themselves or are no longer causing the “Check Engine” light to illuminate. They typically do not require immediate attention.
- Current Codes: These codes represent the current or active problems that require immediate diagnosis. It indicates a present issue or malfunction in a specific system or component of the vehicle that needs to be addressed. They will remain displayed until the underlying issue is resolved.
- Stored Codes: These codes are inactive but remain stored in the computer’s memory, serving as a record of previous issues. These can provide additional information about past issues as a historical reference for previous faults. While they may not be active, they can offer insights into the vehicle’s history and aid in the diagnostic process.
Please click here if you want to know more about the history, current, and stored DTCs.
The purpose of Live Data and Freeze data?
Live data allows you to monitor real-time sensor readings, providing valuable insights into the car’s operation. On the other hand, Freeze frame data captures a snapshot of vehicle conditions when a fault code is triggered. Analyzing this data provides context and aids in pinpointing the root cause of the issue.
Frequently Asked Questions:
Can I clear DTCs myself?
Yes! While clearing DTCs can temporarily turn off the “Check Engine” light, it doesn’t address the underlying issue. It’s recommended to have a qualified mechanic diagnose and repair the problem first before you clear all the codes. You can also ask for professional assistance.
How often should I check for DTCs?
Regularly checking for DTCs can help you identify potential issues early on, preventing more serious problems down the road. You can also use it whenever a check engine light illuminates to diagnose or check why your car is acting up.
What are the benefits of using a professional-grade scanner?
Professional-grade scanners provide more detailed information, manufacturer-specific codes, guided diagnostics, and component testing capabilities, making them a valuable tool for accurate diagnosis and repair.
What are the most common Scion DTCs?
The specific DTCs vary depending on the vehicle’s model and year. However, some common ones include P0171 (system too lean), P0304 (cylinder 4 misfires detected), and P0422 (catalyst system efficiency below threshold).
References
- The Drive – What Is an OBD2 Scanner and How Does It Work?
What Is an OBD2 Scanner and How Does It Work? | The Drive - YOUCANIC – DTC Fault Codes
DTC Fault Codes – YOUCANIC - Consumer Reports – What Does the Check Engine Light Look Like, and What Does It Mean?
What Does the Check Engine Light Look Like, and Really Mean? – Consumer Reports - YOUCANIC – Current / Stored / Active / Past / History Fault Codes Explained
Current / Stored / Active / Past / History Fault Codes Explained – YOUCANIC









