2003 INFINITI FX35 Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 2003 INFINITI FX35: Common Causes and Solutions

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Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Emissions System
0%
60% chance it's
Something else
The most common reasons a 2003 INFINITI FX35 has a check engine light are an emissions system component, a sensor, or a catalytic converter.
  • Emissions System: A faulty emissions system component, such as an oxygen sensor or EGR valve, can lead to increased emissions and trigger the check engine light.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2003 INFINITI FX35 has a check engine light?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A faulty oxygen sensor is one of the most common causes of a check engine light. Symptoms may include a decrease in fuel mileage, hesitation or misfiring from the engine, rough idling or even stalling. A faulty sensor may cause the vehicle to fail an emissions test.

Any time there is an emissions fault the check engine light will be displayed. The purpose of the check engine light is to inform the driver that an emission related fault has been found, and that there are on-board diagnostic (OBD) trouble codes stored in the powertrain or engine control module. Additionally, since the emissions systems are so intertwined into engine control and transmission control systems, symptoms may include nearly any sort of drivability concerns. This may include harsh shifting, failure to shift, hesitation on acceleration, jerking, engine failure to start or run, loss of power, or any number of other drivability issues.

Due to the nature of electrical systems on modern vehicles, the range of problems these can cause are nearly limitless. However, there is a way to categorize them in two ways. Permanent and intermittent problems. Permanent problems appear and remain. This may be the vehicle will not start, the radio does not work, or the door chime will not turn off among many, many others. These problems are more straight-forward to diagnose since they present themselves at all time. This means there will always be a fault to find. Intermittent electrical problems, however, can be difficult or impossible to locate, since they appear then disappear without warning. The best case scenario for an intermittent issue is when replicating the problem is easily accomplished and understood. This allows a technician to make an issue semi-permanent, allowing them to find the fault. Other issues that come and go without warning and cannot be replicated on demand must occur when the technician is servicing the vehicle, otherwise there is no problem to correct. It is most important to understand that electrical system faults always require inspection, and can include the vehicle working in any manner, or not working at all.

Like we noted in the last section, general diagnosis symptoms are the most vague of the bunch. There are several diagnostic spectrums, electrical diagnosis, drivability diagnostics, engine diagnostics, transmission diagnostics, and the list could continue for about 5 or 10 more spectrums of diagnostics. The most important take-away here, is that general diagnostics are diagnostics that have no other spectrum in which they fit, or the problem is unknown. This means that any vehicle left outside of a repair facility with the keys and an authorization to perform diagnosis will be diagnosed under the general diagnosis spectrum.

When the Check Engine Light comes on, you may experience engine performance issues such as poor acceleration, rough idling, or an engine that won't start. In some cases, no abnormal symptoms will be experienced. Other systems like the transmission or ABS can cause the Check Engine Light to illuminate and lights for those systems can come on at the same time. Similar lights may say "Check Engine Soon", "Malfunction Indicator Light" or just "Check". In rare case the engine can overheat.

What are the diagnostic steps to take for a check engine light on a 2003 INFINITI FX35?

When faced with a check engine light on your 2003 INFINITI FX35, it's essential to adopt a methodical diagnostic approach. Start by checking the gas cap; a loose or improperly sealed cap is a common and easily fixable cause of the warning light. If that doesn’t resolve the issue, utilize an OBD-II scanner to read the error codes, which will guide you toward the specific problem. Next, inspect the spark plugs for wear, as faulty plugs can lead to engine misfires and trigger the light. Following this, examine the mass airflow sensor and oxygen sensor for dirt or damage, as these components are crucial for optimal engine performance. Additionally, check the catalytic converter for any signs of clogging or damage, as issues here can also illuminate the check engine light. If these steps do not yield results, it may be time to consult a qualified mechanic for a more in-depth diagnosis. By systematically addressing these potential issues, you can effectively troubleshoot the check engine light and maintain your vehicle's performance.

What are the common problems that could cause the check engine light to illuminate in a 2003 INFINITI FX35?

When the check engine light comes on in a 2003 INFINITI FX35, it can be a source of concern for any DIY car owner. One of the most straightforward issues to check is the gas cap; a loose or damaged cap can easily trigger the light, so ensuring it is secure is a good first step. If the gas cap is fine, the next likely culprit could be the oxygen sensor, which monitors the exhaust and can fail over time, affecting engine performance. Another common issue is the catalytic converter, which can become clogged or inefficient, leading to increased emissions and triggering the light. Additionally, problems with the mass airflow sensor, which measures the amount of air entering the engine, can also cause the check engine light to illuminate. Spark plugs and ignition coils are critical for engine ignition, and if they are faulty, they can lead to misfires and trigger the warning light. Lastly, a malfunctioning thermostat can cause the engine to overheat or run inefficiently, prompting the check engine light to activate. Addressing these issues promptly is crucial to maintaining the vehicle's performance and preventing further damage, making it essential for DIY enthusiasts to diagnose and resolve these common problems effectively.

How urgent is it to address the check engine light in a 2003 INFINITI FX35?

When the check engine light illuminates in your 2003 INFINITI FX35, it is essential to recognize the urgency of the situation. This warning indicator is not merely a nuisance; it signifies potential issues within the engine or emissions system that could compromise your vehicle's performance and efficiency. Ignoring this light can lead to escalating problems, resulting in costly repairs or even a breakdown. For DIY enthusiasts, the first step is to use an OBD-II scanner to retrieve diagnostic trouble codes, which can provide insight into the specific issue at hand. Addressing these codes promptly can help you identify and resolve underlying problems before they escalate, ensuring your vehicle remains in optimal condition. Remember, timely action not only protects your investment but also enhances your safety on the road. Therefore, if the check engine light comes on, take it seriously and investigate the cause as soon as possible to prevent further damage and maintain the reliability of your INFINITI FX35.

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