There’s nothing more annoying than that pesky CHECK ENGINE light appearing on your instrument panel when you know there’s absolutely nothing wrong with your Jeep. The light can appear for a multitude of reasons, some of which are a bit unnecessary or completely unrelated to your engine. The fact remains, we shouldn’t ignore this warning signal and have the problem rectified and the fault code cleared ASAP. But what if you don’t have access to a professional OBD2 scanner to read and clear fault codes? Is there a way you can manually check an error code on your dash and clear it without any fancy equipment? Let’s find out!
If you drive a JEEP Wrangler JK, you can check engine fault codes by inserting the key into the ignition and turning it 3x to the run position without starting the vehicle. Turning the key 3x tells the OBD (On-Board Diagnostics) computer there have been 3 bad runs with the same error and it throws out a code on the instrument panel.
Fantastic! So if you didn’t already know about this trick, you do now. But what is the procedure to clear the codes? We generally don’t want to clear engine codes and pretend nothing is wrong, however, if you’ve done some maintenance work and disconnected a component with an electronic sensor, your vehicle diagnostic system will detect something has changed and throws out a code. Maybe it was just some cleaning on a throttle body unit or you accidentally left your fuel cap open, and now you’re driving around with this annoying orange light glaring at you.
Let’s see how we can reset the code without an OOBD2 scanner tool to read and clear any fault codes.
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Jeep Wrangler Check Engine Light Reset
All modern jeeps come equipped with a PCM or (Powertrain Control Module) which scans all sensors and signals from components throughout the vehicle. When the PCM detects any problems it sends a code that is displayed in your instrument panel.
So when you get an error code appearing, it is essentially the “brains” of your Jeep providing you with vital information telling you, something is wrong and you need to take action.
How to Clear Codes on Jeep Wrangler
Let’s assume, there was a mechanical fault, which you’ve since rectified, how do we go about resetting the error code?
Resetting the Check Engine Light:
- Make sure the engine is not running and the key is out of the ignition
- Disconnect the battery terminals
- Wait 5 minutes
- Reconnect battery terminals
- Insert and turn the ignition key to the run position without starting.
- All error codes are cleared and the CHECK ENGINE icon disappeared.
So what’s the purpose of disconnecting the battery terminals when you have error codes and the check engine light?
Well, what happens is once you disconnect the main source i.e. the main battery, all the stored energy inside the electronic capacitors and modules lose their memory and all settings are reverted back to default. Any error codes that were stored in onboard memory banks are all erased. When electrical energy is sent to the capacitors it is called charging and releasing the energy from a capacitor by disconnecting the battery is known as discharging. It only takes a few seconds for some capacitors to lose their energy and memory.
The nice thing about the engine codes is they give a reference point to start troubleshooting and diagnosing the problem. You can then hop online and check what the code means and begin the repair process.
But what if you have a CHECK ENGINE light, but no codes?
Let’s see what that means.
How to Pull the Codes on the Instrument Panel
The process to read what codes are being pulled by the PCM is fairly simple.
Follow the below process to read what fault codes are being generated:
- Make sure the driver’s door is closed
- Insert and turn the ignition key from off to run 3x consecutively without starting.
- The key should end in the ON position
- Your Odometer will do a reading and display any error codes
Some owners reported that this method does not display any error codes. If that’s the case repeat the above procedure but instead of turning from OFF to ON, turn from ON to ACC (Accessories) Position 3x. If you still find no success with this process, you might have a faulty dash code reader and you’ll need an OBD2 Scanner to read and clear any codes.
Jeep Wrangler Check Engine Light No Codes
Manny Jeep Wrangler owners have at some point experienced the CHECK ENGINE light but no error codes show up on the instrument panel. Is this something to worry about?
Most reports indicate that the Check engine light went away after a battery reset or after a few days of normal driving. Many didn’t report any weird behavior and everything appeared ok in terms of performance and behavior.
So what could be the possible cause of this?
Well, many reports show that almost all of the owners reported bad fuel as being the possible culprit. After filling up at a dodgy gas station they’ve experienced this error. Some reported weird smells after filling up certain at gas stations and shortly thereafter a CHECK ENGINE light appeared without any codes.
So you can possibly put it down to bad gas
The other possibility is, there is an error code but the PCM (Power Control Module) isn’t throwing out any codes. If you have an OBD2 scanner, in almost all cases the code does appear on the scanner. So you’ll do well to invest in one of these scanners if you own a modern vehicle since you don’t want to be running to the dealer only for them to charge you over $100, just to tell you everything is A-OK!
Also, if you are fond of extended off-road traveling to isolated places, where mechanical assistance is hundreds of miles away, a decent ODB2 scanner tool will come in very handy. You will at least be able to diagnose your problem, allowing you to do some DIY repairs to get you home.
So the two possible causes of CHECK ENGINE but no codes are:
- Bad Fuel
- Hidden Code
What Does the Check Engine Light Mean on A Jeep Wrangler?
When your Jeep throws up a CHECK ENGINE light it means something is amiss and it has detected some mechanical problem with a component or an electrical signal error in the Jeeps system.
The Code is very vague since you’ll never know what it means unless you have the service manual or an OBD scanner that can give you more detail about the code.
Click here to download a complete list of Error Codes and Their Descriptions
Jeeps are amazing machines and those who own them, love them. The more modern Jeeps tend to be a bit more finicky, the more sophisticated they get. Unfortunately, that’s the direction manufacturers are going with a strong emphasis on emissions and safety over everything else. This means your vehicle is packed with all sorts of electronic sensors and modules to read any potential errors.
If you can self-diagnose these error codes with an OBD2 scanner and are able to repair your Jeep and clear the codes, it will save you plenty of unnecessary trips to the dealerships and days without your Jeep. It also allows you to be more independent and gives you more confidence when venturing off into uncharted territory.