Car won’t start key turns and lights dim when it cranks. I just don’t hear a buzzing sound from the fuel pump when turn key to on
The car headlights turn on and everything else but when I try to started they just dim and turn back on once I stop. I don't hear the buzzin sound when key is on position from the fuel pump or when car turns off I don't hear a sound that I think comes from throttle body. Put the scanner on and it throws me code U1100 and also my gas cap won't click.
Experienced mechanics share their insights in answering this question :
Code U1100 signifies a communications error which is either a module fault or a deficiency in the wiring harness between communicating modules. There’s a possibility that a dying battery is a cause of such a code (and a cause of your no start condition, as well) and so the very first thing to do is be sure you have a fully, 100% charged battery that passes a load test. Then, confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the immobilizer system is on, you may see a security warning light. To temporarily override the immobilizer system, see these instructions.
If the battery tests good after an actual load test, attempt to start the car. If there is no starter motor operation at all, that is if there is no starter operation with the key held in the "start" position, the procedure is to test for power and voltage drops to the starter motor/solenoid. If there is no power, or a large voltage drop is measured, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch, neutral start switch, and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, IF the starter motor is getting power but the starter does not work, then the starter is condemned and replaced. On the other hand, if the starter motor is NOT getting power, then the circuit is diagnosed and that diagnostic, in your circumstance, may have a tie-in to the U1100 code. That remains to be seen, of course.
If the above protocol does not identify the issue for you, please simply request a no start diagnostic and the responding certified mechanic will get this taken care of for you promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
If you suspect your battery is dying, test your headlights; they`ll be very dim, flicker or won`t turn on if the battery needs charging. No Radio / Chimes – If you put your key in the ignition and you don`t hear the usual chimes, it`s likely a battery issue.
If you don`t hear clicking when you start the engine, the problem may be a dead battery. If you hear clicking, but the engine doesn`t crank, the starter might not be getting enough electricity. Using your owner`s manual and a voltmeter, you should be able to test functionality.
The most common reason cars don`t start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire. If something`s wrong with your battery, your car engine won`t turn over.
Wrong Track: Because the starter motor uses a lot of electricity. There`s only so much to go around and so your headlights dim. Wrong Track: The car needs electrical power to start, therefore the car dumps the power going to the headlights. That`s why.
If the alternator is failing, the voltage to your headlights will drop and they will become dimmer. If your headlights seem to be even dimmer than previously, the chances are the issue is with the alternator.
Most likely, flickering dash lights are due to problems with the alternator. In addition to recharging the battery, the alternator is in control of running the electrical components in your vehicle. If the alternator is failing, it may not be able to steadily supply enough current to all the components.
Why won`t my car start but the battery is good? If your car won`t start but the battery is good, the most common cause is a faulty starter – though it could also be to do with your fuel. You may have insufficient fuel to get the car going.
If nothing happens when you turn the ignition key to the “Start” position, it means that the starter motor doesn`t turn over the engine. Most commonly this could be caused by a low battery; read above How to check the battery.
Bad Sensors
One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn`t working, the spark plugs won`t fire, keeping the engine from starting.
When your battery starts to go, all of the electrical components of your car will be affected. If your headlights dim while idling and brighten when accelerating, your battery isn`t holding a charge anymore.
What to do when the alternator warning light is on. As mentioned before, if this light is on, it means that your engine cannot produce enough power to keep itself running. Turning off all non essential accessories will help increase the distance you will be able to travel with a poorly charged battery.
An early warning sign that your alternator is going bad could be dim, flickering lights. This symptom could show up on any or all of your dashboard lights, reading lights, headlights or other lights. The alternator is supposed to provide the electricity for your car`s lights.
Replacing a Starter
The starter is the part in your car that allows the engine to fire up. The signs that indicate it may be time to invest in a new starter include: Pulsating or flickering dashboard lights.
Bad bulbs or fuses
If the car battery isn`t the reason for your flickering car lights, it may be a bad light bulb or a bad fuse. Bulbs are an easy and quick fix and present an opportunity to upgrade to new energy-efficient LED bulbs.
Faulty wiring is a common cause of flickering lights and a leading cause of electrical fires. Wiring can come loose due to incorrect installation, general wear and tear, and age.
Replacing a Starter
The starter is the part in your car that allows the engine to fire up. The signs that indicate it may be time to invest in a new starter include: Pulsating or flickering dashboard lights.
If your car won`t start, but your battery is fine, chances are you have a bad alternator. This is another charging system issue, like a dead battery, that won`t let you start your car.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Car won’t start key turns and lights dim when it cranks. I just don’t hear a buzzing sound from the fuel pump when turn key to on
ANSWER : Code U1100 signifies a communications error which is either a module fault or a deficiency in the wiring harness between communicating modules. There’s a possibility that a dying battery is a cause of such a code (and a cause of your no start condition, as well) and so the very first thing to do is be sure you have a fully, 100% charged battery that passes a load test. Then, confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the immobilizer system is on, you may see a security warning light. To temporarily override the immobilizer system, see these instructions.
If the battery tests good after an actual load test, attempt to start the car. If there is no starter motor operation at all, that is if there is no starter operation with the key held in the "start" position, the procedure is to test for power and voltage drops to the starter motor/solenoid. If there is no power, or a large voltage drop is measured, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch, neutral start switch, and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, IF the starter motor is getting power but the starter does not work, then the starter is condemned and replaced. On the other hand, if the starter motor is NOT getting power, then the circuit is diagnosed and that diagnostic, in your circumstance, may have a tie-in to the U1100 code. That remains to be seen, of course.
If the above protocol does not identify the issue for you, please simply request a no start diagnostic and the responding certified mechanic will get this taken care of for you promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Battery and oil light come on when trying to start car, take keys out try again car starts no problem and lights go away
ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.
If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Car won’t start. The check engine light, battery light, and oil change light are coming on. I tried jumping the car and nothing happened. Why won’t my car start?
ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.
Car won’t turn over. No lights come on when I turn it. Can’t even lock my doorsvor push the seat up or back.
ANSWER : Your probably correct, it sounds as though your battery is done. But it also sounds like you have charging system issues. I’m not sure that fixing your battery and charging system will solve the problem with the car shutting off, but it’s possible that it will and it’s a darned good place to start. By contacting Your Mechanic, you can have a technician come to your home or office to check out your car and help you figure out what to do next.
Car sounds like its not getting fuel cranks normal. Fuel pump is working. Fuses and relays good. crank no start. No codes
ANSWER : Hi There,
Try starting the car and if it does not start, turn the key off and then pull one of the spark plugs out to see if it is wet with fuel. If the spark plug is dry, then you know you have a fuel supply problem. If the spark plug is wet with fuel, I would suggest next checking for spark issues such as a failed ignition coil. Ignition coils are prone to randomly failing and causing the car to not start without warning as you describe. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.
When I go to crank my car the key stays in the start position and the car is constantly trying to crank itself.
ANSWER : First, let’s make sure about some terminology before I proceed. I will assume the motor is actually turning over. If the car is trying to start, the motor has to be turning over or it is not trying to start. This is an important distinction when diagnosing the starting system. As a technician, I go to different parts of the system based on this description.
If the key is stuck in the start position, this is a ignition lock cylinder issue and the reason the starter continues to turn the motor over. If the starter is turning but the motor is not, then the starter is likely the problem. Either that or the teeth on the flex plate are all gone. This would require removing the transmission to repair.
If the car runs intermittently, this can be a big challenge. And it also means the starting system is working. It will need to be diagnosed when it is failing. A working car cannot be diagnosed because there is nothing wrong. Where you park your car should not have any affect. It certainly could be a wiring problem. Wiring problems hide really well and can happen anywhere in the miles of wires that are in your car. Isolating the system that is failing is really important here. At the moment I am unsure which system is failing. Starter system, ignition lock cylinder and or ignition switch electrical or something with the engine control system.
When the car is failing, you need to check for spark and fuel pressure. If neither is present, this is a clue. Usually the crank sensor will do this. Does your car have a tachometer? If so, does it move at all when cranking. This is a clue whether or not the cam and or crank sensor is working. Is there a Check Engine Light on with the key on? If there is a Check Engine Light, the code or codes can be used for specific diagnosis.
All of these concerns will send you down a diagnostic path. Be sure not to confuse yourself by misinterpreting multiple system failures. If the key does stick in the start position, this would be the first problem to solve. After that, does the motor actually turn when the starter turns? After that, the question of "Why won’t it start?" is first answered by finding what the motor is lacking. Fuel, spark etc… Good luck.
If you need assistance with these checks, contact a certified mechanic who has the tools and experience needed to properly diagnose this starting issue with your car.
Car won’t start
ANSWER : Hello there, many faults will cause your 2003 Oldsmobile Alero to not start. You have done well in determining the battery needs replaced, when the battery begins to die it can cause strange intermittent electrical problems before it dies fully. Replacing the battery could solve the issues you are having. If it does not then other potential causes are the fuel pump, starter, ignition switch, fuel filter, battery cable, or a wiring harness fault. A qualified Technician such as one from YourMechanic will be able to diagnose your starting issues and make any repairs required.
Car will crank but no start… Fuel pump not coming on. New pump, relay, etc. Will start when hot wire runs from pump wires to bat
ANSWER : There are a couple of approaches to take here – either start from the battery and work "towards" the fuel pump, fuse box, ignition switch, fuel pump relay, and wiring connections in between. Or, as you have done, start at the pump with 12v, and move backwards towards the battery. This will require a GM service manual, or wiring diagram at least, with connection locations as well.
I would recommend having a certified technician from YourMechanic diagnose this starting issue, get an accurate assessment of damage and cost estimate for repairs. YourMechanic.com can dispatch a mobile, professional mechanic to your location for this repair.
