We’ve Scanned More Than 110,000 Jeeps with the FIXD OBD2 scanner and app. These Are the 5 Most Common Reasons for a Jeep Check Engine Light to Come On.
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5 Most Common Reasons for a Check Engine Light in Your Jeep
|P0456||Low||Evaporative emission control system leak (small) – There is a small leak in the Jeep’s EVAP system, which could affect fuel economy. This is commonly referred to as the gas cap light since one main cause is a loose gas cap.|
|C0077||Low||Low tire pressure – either one of the tires has low pressure or one of the tire pressure sensors is faulty.|
|P0300||Severe||Random/Multiple cylinder misfire detected – one or more cylinders is not firing properly, which can be caused by a number of issues including the fuel and ignition systems or a major internal engine failure.|
|P0455||Low||Evaporative emission control system leak (large) – There is a large leak in the Jeep’s EVAP system, which could affect fuel economy.|
|P0128||Low||Coolant thermostat temperature below regulating temperature – your engine is not running at an optimal temperature indicating an issue with your Jeep’s cooling system.|
Other Common Jeep Warning Lights
- No bus
- No fuse
What Does It Mean When You See Either Of These Warning Lights?
In addition to a check engine light, some Jeeps have additional warning lights that you should be aware of. These lights will illuminate in the digital display for the odometer.
A “no fuse” warning in your gauge cluster suggests that the Ignition Off Draw (IOD) fuse has blown. Locate this fuse by consulting your owner’s manual and give it a visual inspection to verify if it’s bad. A “no bus” warning is triggered when the computer system is having a hard time communicating with a component. In this case, double check any wiring or connectors that may have been unplugged during a DIY repair.
What Should I Do If the Check Engine Light Is On in My Jeep?
There are thousands of reasons why the check engine light symbol could be illuminated. These range in degrees of severity from a simple loose gas cap to a more serious internal engine failure. If the Jeep check engine light is on, there’s no need for immediate panic, but you also shouldn’t put off diagnosing the problem as it could get worse. Follow the steps below to find out what is wrong with your Jeep, and get the issue repaired yourself or taken to a trusted repair shop for service.
What the Check Engine Light Means
Your Jeep’s check engine light is part of the onboard diagnostics system (OBD2). Since 1996, all gas-powered passenger vehicles use OBD2 that allows the computer to communicate with other vehicle systems to ensure proper operation. The Jeep check engine light comes on when the computer detects a problem, and it provides a variety of diagnostic trouble codes (or DTCs) based on the issue detected to relay this information to whoever is diagnosing the issue.
OBD2 scanners like FIXD allow DIYers to easily read these codes to understand what’s wrong with your Jeep and the severity of the problem.
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How to Read Your Jeep’s Check Engine Light
If your Jeep check engine light comes on, you have several options for reading the diagnostic trouble codes:
1) Go to your local mechanic. When most people see a check engine light, they head to a repair shop, which charges a diagnostic fee to read the code with a professional OBD2 scan tool and identify the cause. This becomes an inconvenience if you aren’t near a repair shop. Also, once the shop has your Jeep on the lift and diagnosed, you could get a hard sell from the service advisor to get the repair performed immediately.
2) Go to a nearby auto parts store. Most major auto parts stores are able to provide basic code reading for check engine lights as a free service. Again, if your check engine light comes on when you’re in the middle of nowhere, this really doesn’t help the matter. Additionally, the auto parts store is just able to give you a code and guess what could be wrong with your Jeep, so it could end up costing you more in the long run.
3) Get the FIXD car scanner to read your own codes. For added peace of mind wherever you are, the FIXD OBD2 scanner and app can show what caused your Jeep’s check engine light to come on. This data is translated into plain English directly onto your smartphone, and it helps diagnose the problem and properly repair it whether you are doing it yourself or taking it to a shop.
How the FIXD Check Engine Scanner Works
The FIXD car scanner plugs into the OBD2 port. This port is usually located on the driver’s side of the Jeep under the dash.
This port is usually located on the driver’s side of the Jeep under the dash.
Can’t find it? Read our post on how to locate your OBD2 port. Once connected to your Jeep, the FIXD Sensor and free mobile app tells you what your check engine light means in plain English, so that you can walk into the repair shop armed with accurate, detailed information.
Understand Your CEL
FIXD instantly translates over 7,000 error codes into simple terms right on your phone.
See How Serious Your CEL Is
The risks of driving with a check engine light illuminated vary from low to severe, so using FIXD to determine the problem as soon as the CEL comes on is a helpful advantage to keeping you and your Jeep safe. Find out how serious your code is and whether or not it’s safe to keep driving.
Get Maintenance Alerts
FIXD is also beneficial because it reminds you when it’s time to perform maintenance on your Jeep. This includes any type of routine and preventative maintenance that varies based on make, model, and mileage.
Monitor the Health of Your Jeep in Real Time
FIXD shows you how healthy your Jeep is by sending you real-time notifications about any check engine lights. You can also view live data for your Jeep while you’re driving, including oxygen sensor voltage, fuel trims, vehicle speed, and more.
Does FIXD Work with Your Jeep?
FIXD is compatible with all gas-powered Jeep models made in 1996 or newer and all diesel models 2008 or newer. Use the Compatibility Checker for additional info.
Is It Safe to Drive with My Check Engine Light On?
The check engine light is tied to your Jeep’s onboard diagnostics system, so you’ll need a code reader or OBD2 scan tool like the FIXD Sensor to understand the severity of the issue and whether or not you should keep driving.
The most common reason for a check engine light on modern vehicles is actually a loose or missing gas cap. This light happens because the engine detects a leak in the evaporative emissions system, and it can easily be resolved by tightening the cap.
However, if the check engine light is blinking in your Jeep while you’re driving, you should pull over as soon as you safely can to check for low oil or overheating. If you experience drivability issues along with the engine light, reduce your speed and take it easy on the engine to avoid potentially bigger problems. Some problems will automatically trigger reduced speed and engine power, and this is called “limp mode.”
How Can I Reset the Jeep Check Engine Light?
Whenever you perform a repair or resolve an issue, you should clear the DTC, which will turn off the check engine light. You can quickly and easily reset a Jeep check engine light with FIXD.
Simply click “Clear Engine Light” on the details page after you’ve performed an engine scan. If the code is cleared but the issue has not been resolved, the warning light will reappear after driving a few miles. Repair shops can charge $100+ to do this for you, but it’s free in the FIXD app.
Diagnose Your Jeep’s Check Engine Light with FIXD
Still wondering what to do about that pesky check engine light on your Jeep? Take the first step to clarity by getting FIXD, America’s favorite check engine scanner and app. Get detailed engine diagnostics, plain English code descriptions, issue severity warnings, and so much more. Learn more about the FIXD Sensor and mobile app today!
Lifelong automotive enthusiast with a soft spot for offroading. Wrencher turned writer, but I still love to tinker on just about anything with an engine. Dream car: tie between a ‘71 Hemi ‘Cuda and a ’91 GMC Syclone. #GirlDad #SaveTheManuals