Fiat Check Engine Light Troubleshooting Guide

Fiat Check Engine Light Troubleshooting Guide

Last Updated on Thursday Jun 14, 2018

Fiat Check Engine Light (CEL) may come on and stay on. In addition in newer Fiat models such as late model Fiat 500, you may also get  "HAVE YOUR ENGINE CHECKED" message on dashboard. The problem could be something as simple as a loose gas cap (fault code P0456) or an indication of another problem ranging from turbo boost issue, engine malfunction or misfire and even transmission problem.

In this guide, you will find instructions on how to diagnose Fiat check engine light yourself. Plus lots of information to help you better understand the CEL on your fiat. 

FIAT CHECK ENGINE LIGHT SYMBOLThe light itself does not provide much information other than warn you to get the car diagnosed as soon as possible. Without reading the codes, it is impossible to know why your Fiat check engine light is on. In this guide, you will learn how to use a various OBD-II scanner to read the codes yourself and take a quick look at common Fiat check engine problems.

The symptoms of Fiat check engine light are not usually the same and sometimes, you may not notice any performance issues at all. On the other hand, symptoms may be more serious such as:

  • poor throttle response,
  • engine jerking when changing gears,
  • engine overheating
  • "high coolant temp, turn the engine off" warning,
  • engine stalls at idle or car is difficult to start. 

If you don't notice any performance issues, you can continue to drive your Fiat but get it diagnosed as soon as possible. Your Fiat dealer will diagnose your check engine light for a fee. The average cost to diagnose a Fiat at the dealer or mechanic ranges between $60 and $120. As a Fiat owner, you can also read the check engine light codes yourself as outlined below. 

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1. How to read Fiat Check Engine Light 

You can stop by a local auto parts store (Autozone, Advance Auto, PepBoys) and ask if they read codes for free. If not, follow the instructions below to learn how to read and clear Fiat to check engine light. You will need an OBD-II scanner which you can purchase online for as little as $20 USD. 


The following instructions work on Fiat vehicles manufactured from 1996 to present. Following these steps you will be able to read Fiat codes on models such as Fiat 500, 500x, Abarth, Panda, Fremont, Viaggio, Ottimo, Ducato, Dublo, Tipo, Toro, Mobi, Argo, Punto, Panda, Croma, Seidici, Bravo etc. 




  1. Turn on Ignition. All your dashboard lights should be on. It is not necessary to start the engine. fiat cel on, turn on ignition
  2. Plug in your scanner into the OBD II port under the obd2 port location to diagnose check engine lightHere is how your Fiat OBD II port looks obd port locaitonThere is only one port like this. Sometimes it has a small cover, so you may not notice it easily. It may be hidden under the dashboard as well, which will require you to look carefully under the dashboard.
  3. Allow the scanner to communicate with your Fiat and detect the correct protocol. fiat check engine scanner


  4. Press read codes on your OBDII scanner or phone app to retrieve the codes. 


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2. Fait Check Engine Scan Tools

In this section, we will take a look at how to use various OBD-II scanners to diagnose Fiat check engine light. The first step is to read the codes using a scan tool that can read Fiat fault codes. Always fix the underlying problem before you reset Fiat check engine light. If you reset the light without fixing the problem the check engine light on your Fiat will come back on. Depending on the code it will come back as soon as you restart the car or it can take up to one week.

There are hundred of OBD-II scanners available on the market that can read and clear Fiat fault codes (DTCs). We could not test all of them. Instead decided to show you how to use some of the most popular OBD-II scanners for Fiat vehicles. 

MaxiScan Scan Tool

What we used: MaxiScan MS309


Bluetooth Adapter + SmartPhone Scan Tool

What we used: ELM327 Bluetooth Adapter + Torque App


Launch Engine, Transmission, ABS, Airbag Tool

What we used: Launch Creader VIII


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3. Read codes, what's next? 

It is strongly recommended to write down the code and research the problem. Many owners get a code and start replacing parts based on the code alone. Later they find out that the replaced part didn't fix the problem. Don't start replacing parts without doing research on the code first. There are more than one problems that can trigger one code. 

Loose Gas Cap

fiat loose gas cap triggered check engine lightIf you scan your Fiat and the code that you get is for a loose gas cap, make sure you tighten the gas cap until you hear two clicks. You can also use an OBD-II scanner and clear the code once you tighten the gas cap.  If the CEL comes back replace the gas cap.

If the CEL comes back on again, with a code for a small EVAP system leak, have a mechanic or your Fiat dealer would have to perform a smoke test to find the leak.  You could have a leak at the detector evaporative system integrity module. It is possible for a leak to develop at the filler neck as well. Without performing a leak test it is impossible to determine where the leak has developed.

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4. Fiat Check Engine Light Flashing

If your Fiat check engine light is flashing, it means that the onboard diagnostic system (OBD) has detected engine misfire. In other words, one or more of the cylinders is not working properly. It is not recommended to drive your Fiat if the check engine light is flashing. Driving your Fiat with CEL flashing can cause more damage to the engine and catalytic converter. 

As long as your Fiat check engine light is NOT flashing, it is usually safe to drive. If you decide to drive your Fiat when the CEL stays on, you should carefully monitor dashboard warning lights and the engine temperature. Do not drive if the engine is shaking or hesitates when pressing the gas.

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5. Common Problem that Triggers Fiat Check Engine Light

Some of the most common problems with Fiat such as 500 are listed below. Note that there are many more possible problems and hundreds of Diagnostic Trouble Codes (DTC) that can trigger the CEL on your Fiat. Without diagnosing the vehicle it is difficult to know what the problem is in your particular case. 

  • Poor fuel: Low-quality gasoline can trigger the CEL on Fiat vehicles
  • Turbo problem: Under boost pressure
  • Thermostat: Engine overheats or takes too long to reach operating temperature
  • Oxygen sensor: Increases emissions, a decrease in fuel economy. 
  • Mass air flow sensor: Often results in multiple codes and poor throttle response
  • Spark plugs: If one fails it will cause engine misfire and engine shaking
  • EVAP:   The EVAP emissions canister can fail triggering CEL and codes such as P0499. 
  • PCM: Failure changing spark plugs and wire harness does not fix the CEL. PCM replacement may be required.
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