How to Read and Erase Fiat Fault Codes with an OBD-II Scanner
Your Fiat, a symbol of Italian automotive ingenuity, is a dependable companion on your daily commutes and weekend adventures. However, like any machine, it’s prone to occasional hiccups, and that’s where understanding DTC/Fault Codes comes in. Fiat vehicles now have an OBD-II port for easier diagnosis and repair. This procedure works on all FIAT models, such as 500, 500e, Argo, Mobi, Panda, Tipo, 600, Fastback, Ulysse, Doblo, Fiorino, Scudo, Toro, and newer.
DTC, or Diagnostic Trouble Code, is the vehicle’s way of communicating underlying issues. These codes are like Morse code; your Fiat’s onboard computer warns you through your dashboard with a Check Engine Light or any warning light to alert you of potential problems. Now, almost a hundred warning lights could illuminate your dashboard; these include ABS, SRS, transmission issues, battery charging, differential, traction control, and many more; they seem overwhelming, but how are we gonna get the codes and interpret them? We’ll have to use an OBD-II scanner like our YOUCANIC Scanner.
How to read and delete DTCs/Fault codes
OBD stands for “On-Board Diagnostic”. Most modern vehicles now include an OBD port, which can be utilized by a scanner that communicates to your vehicle. It is plugged in by an OBD-II scanner into the socket designed to help automotive technicians interpret faults and other issues that your Fiat may be experiencing or have recorded. Here are the steps on how to read DTCs or Fault codes:
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- Gather the necessary tools: Equip yourself with a Professional-Grade OBD-II Scanner compatible with your Fiat. 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 Fiat 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.

- Turn on the ignition, but do not start the engine.
- 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 Fiat.

- Select ‘Fiat’ as the Vehicle Make: This ensures the scanner effectively communicates with the Fiat 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 Fiat. 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 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 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.
Can’t Clear Fiat Fault Codes
Clearing fault codes on Fiat vehicles from 2018 and newer can be a bit more challenging due to the introduction of the Security Gateway Module. This module is a security feature designed to prevent unauthorized access to the vehicle’s computer systems, including the ability to read and clear diagnostic trouble codes or send bidirectional commands to operate switches and sensors. This means that even after fixing the underlying problem that triggered the fault code, the code may not be cleared using standard OBD-II scanners.
One effective solution to address this is using a 12+8 bypass cable. This cable bypasses the Security Gateway Module, allowing full access to the vehicle’s diagnostic systems. With this bypass cable connected, technicians and vehicle owners can clear codes, perform diagnostic tests, and send commands to various systems in the car, just like with older models that do not have the SGM. This tool is crucial for anyone looking to perform advanced diagnostics or repairs on newer Fiat vehicles, ensuring they can maintain full functionality and control over their diagnostic capabilities.
Common Fiat Fault Codes and Possible Causes
Here’s a list of the Top 20 common Fiat fault codes with their descriptions and common causes:
- P0300 – Random/Multiple Cylinder Misfire Detected: Caused by issues like faulty spark plugs, ignition coils, or a clogged fuel system.
- P0301 – Cylinder 1 Misfire Detected: Typically due to problems with spark plugs, ignition coils, or fuel injectors in cylinder 1.
- P0302 – Cylinder 2 Misfire Detected: Similar to P0301, but affects cylinder 2, often due to the same issues.
- P0303 – Cylinder 3 Misfire Detected: Similar to P0301, but for cylinder 3.
- P0304 – Cylinder 4 Misfire Detected: Similar to P0301, but for cylinder 4.
- P0171 – System Too Lean (Bank 1): Often caused by vacuum leaks, faulty fuel injectors, or a malfunctioning mass airflow sensor.
- P0172 – System Too Rich (Bank 1): This can result from leaky fuel injectors, a faulty mass airflow sensor, or a malfunctioning oxygen sensor.
- P0420 – Catalyst System Efficiency Below Threshold (Bank 1): Indicates a failing catalytic converter or faulty oxygen sensors.
- P0430 – Catalyst System Efficiency Below Threshold (Bank 2): Similar to P0420, but for Bank 2.
- P0138 – O2 Sensor Circuit High Voltage (Bank 1 Sensor 2): Often caused by a faulty oxygen sensor or wiring issues.
- P0101 – Mass Air Flow Sensor Circuit Range/Performance: This can be due to a dirty or faulty mass air flow sensor.
- P0120 – Throttle/Pedal Position Sensor/Switch A Circuit: This may arise from a faulty throttle position sensor or related wiring.
- P0110 – Intake Air Temperature Sensor Circuit: Indicates problems with the intake air temperature sensor or its circuit.
- P0340 – Camshaft Position Sensor A Circuit (Bank 1 or Single Sensor): Often caused by a faulty camshaft position sensor or timing issues.
- P0335 – Crankshaft Position Sensor A Circuit Malfunction: This can result from a bad crankshaft position sensor or related wiring.
- P0135 – O2 Sensor Heater Circuit (Bank 1 Sensor 1): Typically due to a faulty oxygen sensor heater element.
- P0443 – Evaporative Emission Control System Purge Control Valve Circuit: This may be caused by a faulty purge solenoid or related components.
- P0401 – Exhaust Gas Recirculation Flow Insufficient Detected: Often results from a clogged EGR valve or malfunctioning components in the EGR system.
- P0562 – System Voltage Low: Indicates electrical system issues, such as a failing alternator or poor battery connection.
- P0700 – Transmission Control System Malfunction: This can be due to various transmission issues or a fault in the transmission control module.
These codes provide insights into potential issues with Fiat vehicles. Accurate diagnosis and repair are essential for resolving these problems.
Why can’t I clear the error codes of my FIAT?
Once you’ve identified the DTCs, you may be tempted to clear them, hoping to continue driving your Fiat, 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 Fiat:
- Use a Professional-Grade Scanner: Ditch the generic scanner and upgrade to a professional-grade like the YOUCANIC. 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 Fiat’s diagnostics, unlocking hidden diagnostic powers and letting you clear codes that would otherwise remain stubborn and hidden.
- Underlying Issues: Before 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: Like the SRS system, certain fault codes may be cleared by disconnecting the battery (like a reset). They will reappear even after clearing until the root cause is resolved. It is a persistent reminder to fix the problem, not just mask it.
- Proper Clearing Procedure: Following the correct steps outlined in your diagnostic scanner’s user manual is essential to clear fault codes effectively. If unsure about the clearing procedure, consult a professional for guidance specific to your scanner and Fiat model.
Check our professional-grade YOUCANIC scanner here:
Frequently Asked Questions
What are DTCs?
DTCs, or Diagnostic Trouble Codes, are alphanumeric codes that your Fiat’s computer stores when it detects a problem,
What happens when I ignore fault codes?
Ignoring fault codes can lead to several problems, including further damage to your vehicle, increased emissions, and failure to pass emissions testing.
Can I scan my Fiat on my own?
Yes, you can scan your vehicle using a professional-grade scanner. It is ideal to know at least how to read codes so you can diagnose them in case of emergencies. If the issue is more complex, consult an authorized Fiat technician.
What is the best OBD-II for DIY Auto Repair?
You can check our article here if you want to know what is the best OBD-II Scanner for DIY Enthusiasts: Best OBD2 Scanner For DIY Auto Repair – YOUCANIC
References:
- What Is an OBD2 Scanner and How Does It Work?
What Is an OBD2 Scanner and How Does It Work? | The Drive - DTC Fault Codes
DTC Fault Codes – YOUCANIC - 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 Report









