1999 Toyota Solara Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 1999 Toyota Solara: 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 1999 Toyota Solara 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 1999 Toyota Solara 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 first steps to diagnose the check engine light on a 1999 Toyota Solara?

To effectively diagnose the check engine light on your 1999 Toyota Solara, start with a thorough visual inspection of the vehicle. Begin by checking the gas cap; ensure it is securely tightened and free from damage, as a faulty gas cap is a common trigger for the check engine light. Next, utilize an OBD-II code reader to scan the vehicle’s onboard computer for any error codes. These codes are invaluable as they pinpoint specific issues within the vehicle’s systems. After retrieving the codes, take the time to interpret them using a reliable code manual or online resource, which will help you understand the underlying problems. Additionally, inspect the wiring and connections under the hood for any signs of wear, damage, or disconnection, as these can also lead to the check engine light being activated. If these initial steps do not resolve the issue or if the problem remains unclear, it may be wise to consult a qualified mechanic for a professional diagnosis. By following this structured approach, you can efficiently identify and address the cause of the check engine light, potentially saving time and money in the repair process.

What are the common problems that could cause the check engine light to illuminate in a 1999 Toyota Solara?

When the check engine light comes on in a 1999 Toyota Solara, it can be a source of concern for any DIY mechanic. One of the most straightforward issues to check is the gas cap; a loose or damaged cap can lead to fuel vapor leaks, triggering the light. Another common culprit is the oxygen sensor, which plays a crucial role in managing fuel efficiency and emissions. If this sensor fails, it can significantly impact your vehicle's performance. Additionally, problems with the catalytic converter can also illuminate the check engine light, often indicating a failure or inefficiency in the emissions system.

The mass airflow sensor is another critical component that, if malfunctioning, can disrupt the air-fuel mixture, leading to engine performance issues. Spark plugs and ignition coils are vital for proper engine operation, and any problems here can result in misfires, which will also trigger the light. Other potential issues include a faulty EGR valve, which affects emissions control, and thermostat problems that can disrupt engine temperature regulation. Vacuum leaks can further complicate matters by altering the air-fuel ratio, while faulty fuel injectors can impact both performance and emissions. Lastly, worn-out spark plug wires can lead to misfires as well, making it essential to inspect these components when the check engine light appears. Understanding these common problems can empower you to diagnose and address the issue effectively, ensuring your Solara runs smoothly.

What should I do if the check engine light comes on in my 1999 Toyota Solara?

When the check engine light illuminates in your 1999 Toyota Solara, it serves as a critical warning that should not be ignored. Ignoring this signal can lead to severe consequences, including costly repairs and safety hazards. The first step is to assess the situation; if the light is flashing, it indicates a serious issue that requires immediate action, such as reducing speed and avoiding sudden maneuvers. A common and simple fix is to check the gas cap, as a loose or damaged cap can often trigger the light. Additionally, inspecting essential fluid levels is crucial, as low engine oil, transmission fluid, or coolant can also activate the warning. If these quick checks do not resolve the issue, it is advisable to schedule a diagnostic test at a local mechanic or auto parts store. This test will pinpoint the specific problem, allowing you to address it effectively. By taking these proactive measures, you not only safeguard your vehicle's performance but also prevent potential safety risks and extensive damage down the line.

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