Maybe it cost you a fortune. Get a Diagnostics App. But hang on a minute, there are other important things to keep in mind. To begin with, there are many vital components in your car and if any fail they can cause the Check Engine Light to come on.
Surprisingly enough it could be something as simple as not tightening a loose gas cap after refuelling! Sounds silly? Sometimes, it could be a faulty car part that that has triggered the check engine light. Some of the common car parts that may cause the check engine light to come on are:.
You can read more about each of these faults and what to do about it on the Check Engine Light page. Careful: quite often, a faulty sensor could be the cause for your check engine light to be on. And if you are not careful you could end up spending a lot of money on an expensive car part, only to find out later on that the issue was a faulty sensor.
Naturally, when your car has an issue you take it to the mechanic for repair. To always be a step ahead of your mechanic. To actually check if the mechanic is telling the truth? When a sensor reports a faulty device the check engine light will come on. The fact is your car has sensors for many components.
Sometimes a sensor will fail or get stuck and report a bad code. If your mechanic is honest enough he will tell you that because replacing a bad sensor is very affordable.
To determine whether the sensor is faulty, you can run a little experiment. Clear the codes from your computer and watch to see if the check engine light comes back on. That way, you will discover why your check engine light is on.
You can get your very own code diagnostic scanner. GOFAR does exactly that and more! If in doubt, just run a quick compatibility test. Once you download the app, it will take you through the setup process with nice, clear pictures — takes a few minutes.
Once you place the ray on the dash, connect it with the adapter using the thin custom cable. How It Works. Drive for 50 to miles 80 to km. Take several individual trips until the system reads the status of all the components once more. Note that when you turn on the ignition without starting the engine, all the panel lights light up temporarily as a test to see that they are all working.When the crank sensor is replaced, it must be resynced to the PCM.
Without resyncing, the PCM cannot properly determine the position of the crankshaft. The proper procedure for resyncing or relearning the crankshaft position is called the "CKP Variation Learn. Shift the GMC vehicle's transmission into park, or first gear for a manual transmission. Apply the parking brake and leave the engine running.
Plug an automotive scan tool's data connector into the vehicle's diagnostic data port. This port is situated underneath the dashboard on the driver's side of the vehicle, to the right of the steering column.
Power on the scan tool and select "PCM" from the main welcome menu. Allow the scan tool to perform the CKP Variation learn procedure. This can take up to 10 minutes. Do not turn off the engine or disconnect the scan tool during this procedure. Remove the scan tool. Turn the engine off, then back on again. Verify that the engine runs smoothly. This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.
To submit your questions or ideas, or to simply learn more about It Still Runs, contact us. Step 1 Shift the GMC vehicle's transmission into park, or first gear for a manual transmission. Step 2 Plug an automotive scan tool's data connector into the vehicle's diagnostic data port.
Step 3 Power on the scan tool and select "PCM" from the main welcome menu. Items you will need Automotive scan tool with relearn capabilities. About the Author This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.If your check engine light keeps coming on after you have repaired your automobile, then this means the trouble code is still in memory.
You will need to clear this code out of the car's computer. Clearing the codes is a simple process and can be done in a matter of minutes. Following the steps will ensure a clean start to your car's computer and no more check engine light flashing. Remove the positive terminal cable from the battery using your pliers or wrench.
Go to your fuse box in your car, and look at the diagram. Select the fuse that is labeled "ECM" and remove this fuse. Sit the fuse aside for now. Keep the car disconnected like this for two to three minutes to clear the computer's memory. Insert the fuse back in to the box.
Reconnect the battery terminal. Your car should now be reset. This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.
To submit your questions or ideas, or to simply learn more about It Still Runs, contact us. How to Reset a Car Computer by Contributor. Step 1 Open up the hood. Step 2 Remove the positive terminal cable from the battery using your pliers or wrench.
Step 3 Go to your fuse box in your car, and look at the diagram. Step 4 Keep the car disconnected like this for two to three minutes to clear the computer's memory. Items you will need Pliers or battery wrench. About the Author This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.View Cart Checkout.
Unless these procedures are correctly performed the vehicle will not start after the PCM has been replaced. The three systems are:. How do you know what system your vehicle has?
Does a Car Have to Relearn Idle When a Battery Is Disconnected?
Just look at the keys see page 4. The sections that follow will help you identify the system and describe how to do the relearn. No relearn is required on a Passkey equipped vehicle when replacing the PCM.
To perform a relearn on a Passkey II system, make sure there is a fully charged battery in the vehicle. The battery will be used for 30 minutes without the alternator available for charging. Connect a battery charger to the battery to ensure power is available while programming. The Passlock anti-theft system requires the presence of a key in the lock cylinder to enable starting. The lock cylinder contains a stationary Hall effect sensor and a rotating magnet. When the key is turned in the lock cylinder, the magnet creates a signal on the Hall effect sensor.
To perform a relearn on a Passlock system, make sure there is a fully charged battery in the vehicle. NOTE: For most cars, one minute cycle will be enough for the vehicle to learn the new password. Perform all 3 cycles if the car will not start after 1 cycle.
Most trucks will require all 3 cycles for learning the password. The Passkey III anti-theft system uses a transponder inside the head of the ignition key. The exciter inside the ignition lock cylinder energizes this transponder when the ignition switch is turned on. The transponder transmits a unique signature to the theft deterrent control module. If the key signature transmitted is acceptable to the theft deterrent control module, the theft deterrent control module will transmit fuel enable password to the PCM.
If the fuel enable password is correct, the PCM will start the vehicle. To perform a relearn on a Passkey III system, make sure there is a fully charged battery in the vehicle.
When performing this relearn, all previously learned keys will be erased. Additional keys may be relearned immediately after the first key has been learned by inserting the additional key and turning the ignition switch to on within 10 seconds of removing the previously learned key. How to tell which system you have — Look at the keys. The Crankshaft Position Sensor Relearn procedure requires the use.
The scan tool will walk the installer through the procedure. Some of the steps to be expected are:. These are example steps, and not in any order. This information can also be found in ProTech Skip to content info ModuleExperts. GM Security Relearn Procedure. Do not attempt to start the engine.
The security light will be steady on or flashing for the minute period. Passlock — coded lock cylinder The Passlock anti-theft system requires the presence of a key in the lock cylinder to enable starting.The car prior to them being changed ran fine. The check engine light went on for a minute about 3 days ago,then went off. It never came back on,but i had the comp scanned and thats how i found out the air charge temp sensor was bad. After the 2 parts were changed,i drove the car.
It ran like new. But as soon as a slowed down to a stop,it would stumble a little for 10 seconds,clear up,and be fine.
It drove ok,at all speeds,until i came to a stop. So basically,it runs good until i stop,and then it stumbles. I took it back to the mechanic ,he scanned it again,and all was ok. He said the computer needs to relearn again. He told me to drive it on the freeway a bit.
It should not take more than a couple of short drives, say 5 miles each or so. The Air charge temp sensor on this vehicle is part of the air flow sensor and he may have used a re-manufactured, which is okay but sometime they can cause strange problems like this. He may need to try another. The mechanic is right that when he disconnected the battery the computer lost its memory, the problem is you have a dirty throttle body and the computer was compensating for the gradual difference as the throttle body got dirty.
The best thing to do now is to clean the throttle body. The computer will eventually learn but will take awhile because it will not make drastic changes all at once. Remove the plastic hose from the throttle body, take a rag and spray with carb cleaner gloves are recommendedopen the throttle plate with one hand and wipe the bore and the plate until clean. So drive it around and mix it up A descent scanner tool will tell you if the car has met every requirement, or if it's still testing the car.
I did do that,but only about 10 miles. It still did it. He disconnected the battery when he replaced the parts too? How long does it take for the computer to relearn? He said the cars so old that the computer has to kick in with the new sensor? Is this true? I dont know too much about this particular cars computer. Answer Save. Eyeswideopen Lv 6. Jim4wild Lv 4. Though frankly, the problem sounds like it could also be a fuel pressure issue Still have questions?
Get your answers by asking now.When taking out an old throttle body and putting a new one in does the computer reset itself to normal idling and functions as it was before the the system went down? Hi there. After replacing the throttle body to your engine, if the engine light was on and has a pending code, the code will go away. If the code was a hard permanent code, then the ECM computer would need a hard reset.
Remove the negative battery cable - and keep it off for about 13 minutes, then hook up the battery cable and make sure it is tight. The engine light will go out and clear all codes as it goes into a learn cycle. If the problem was addressed then the check engine light will remain off, but if something is still not working, then after 10 starts or driving 3 days will make the check engine light come back on, unless it is causing multiple sensors to activate codes.
If you need further assistance with resetting the ECM, then seek out a professional, such as one from Your Mechanic, to help you. Q: After installation of a new throttle body does everything reset to normal function on the car? My car has miles. My car has an automatic transmission. Marvin Sunderland Automotive Mechanic.
Thank Marvin. Was this answer helpful? Thank you for your feedback! Sorry about that. Why wasn't this information helpful? The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details. Related Questions. Car overheated and rattling by Gabrielle C. Would a rack a pinion cause popping when I turn? Battery light is on by Anna V.
The brake locks on me and won't let me start my car. Car clicking and not starting by Christopher A. Home Questions. Year I don't know. What others are asking My PT Cruiser speedometer quit working and when I drive it it only drives in first gear I can shift it but it only drives in Hi Chevy.
How it Works: The Computer Inside Your Car
Thanks for contacting us today. What is likely is that your PT Cruiser is stuck in limp mode; which occurs when the ECU and sensors detect a mechanical or electrical fault with the transmission or other driveline systems Read more. P As you may already know, this may be related to a faulty or leaking gas cap, however this can also be related to several other factors such as the following: A non-conforming gas cap i.
Gauges fluctuate wildly then car turns off. Though there are a lot of common issues that can cause this, the most common is a voltage issue. Low voltage will cause each of these symptoms and codes you are getting. I usually start by testing the ignition Related articles.
Cyl2 specifies that the issue is likely taking place in engine cylinder number 2. What the P code means This code indicates there Browse other content.We plan to reopen Monday, April 13,unless the situation changes again.
Servicing TPMS equipped vehicles profitably can be a challenge without the knowledge, the right parts and the right tools. In spite of all the training programs and technical articles on the subject, there is still a lot of misunderstanding about TPMS, and the confusion between vehicle relearn and sensor programming tops the list.
Unfortunately, some shops overlook the necessary relearn step mistakenly believing the sensor programming did the trick. This misconception can lead to service comebacks and customer complaints. With the exception of some Chrysler and Mazda models that may be relearned to the vehicle via a driving procedure, a TPMS scan tool is required to complete the vehicle relearn procedure.
In addition to this extra step, technicians may also need to invest in additional specialized tools, training and software to complete the process. And even if a shop has the specialized programming tool, it may need to be updated to provide the latest application or software changes in order to meet the specifications of a particular vehicle. These multi-application sensors can help reduce lost service time, eliminate unnecessary expenses and training and cut down on customer complaints and comebacks.
It is pre-programmed and ready for the vehicle relearn procedure as soon as the technician takes it out of the box and installs it in the tire. For more information, visit: www. Subscribe to our email list and receive product news, promotions and product updates delivered right to your inbox. Learn more about our closing here. Vehicle relearn and sensor programming are completely different procedures. Protect your customers and increase profits with TPMS service.