Changed battery car won’t start

Help! I took the battery out of my car. I put it back, all connections are tight. Keyless start wouldn't work. Used the key. Turned it on and some of the lights on the dash were flashing. The drivers side window rolled down but no auto function. Passenger side wouldn't work at all. Turned the car off and tried to turn it back on and now it won't start

My car has 84000 miles.

Experienced mechanics share their insights in answering this question :
See if any diagnostic trouble codes were set via the OBD-II on board diagnostics. Prior to performing diagnostics be sure you have a fully, 100% charged battery. 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. If the warning light is on, to temporarily override the immobilizer system, see these instructions. 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 to the starter motor. If there is no power, then the electrical circuit supplying the motor has a fault (or, somehow the immobilizer system is on). That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition 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 doesn’t work, then the starter is condemned and replaced. Note that starters can and sometimes do develop intermittent faults due to bad spots on the armature. The bottom line is if there is battery voltage to the starter (and no excessive voltage drop) and yet the starter doesn’t work, it’s dead. If you desire that a certified mechanic resolve this, please request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Please let us know if you have further concerns or questions 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 :

A dead battery is often the most common reason your car won`t start. Batteries age out, so if it`s been some time since it was replaced, you should visit us.
The most common reasons a Mazda CX-9 won`t start are a dead battery, an alternator problem, or failed starter.
The most common reasons a Mazda CX-7 key won`t turn are a binding steering column/lock, an ignition switch issue, or a problem with the ignition key. Search our network of RepairPal Certified shops near you to speak with a technician about your issue.
The security indicator light in the instrument cluster flashes every 2 seconds until the system is disarmed. The system is disarmed when the ignition is switched ON with the correct programmed key. The security indicator light illuminates for about 3 seconds and then turns off.
Why won`t my car start but I have power? If you attempt to start up your car but the engine won`t turn over and the dashboard lights up, then you most likely have an issue with your battery. You could have a damaged or corroded battery terminal, which is stopping the engine from starting up when you fully turn the key.
If the car cranks when you turn the key, but the engine won`t start, it could be because fuel isn`t getting to the engine. One potential reason for this could be dirty fuel injectors. Over time, the fuel injector nozzles can become clogged with rust, corrosion or debris.
To disarm the system and start your engine, use the correct, programmed key that came with your Mazda3. The security light will illuminate for three seconds and then turn off.
The issue with the anti-theft system will prevent the car from starting. Until the issue is fixed, you won`t be able to get the car to start again.
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.

The battery can be fully charged but still not be able to start the vehicle if it is failing or has a dead cell. Other likely issues are the fuel pump, ignition switch, battery cables, starter, or a clogged fuel filter.
It is possible that the problems that you have been experiencing with the bad alternators have damaged the battery causing it to be weak. This would make the Battery Light come on. It is also possible that there is a problem with the fusible link or the alternator fuse for the charging system.
Park in a well-ventilated area and turn off the ignition. Look for the negative battery terminal with a black cap and a negative (-) symbol. Loosen the negative terminal bolt and pull the negative cable from the battery. Hold the cable away from the battery for between 30 to 60 seconds.
If your key fob still isn`t functioning after you`ve replaced the batteries, the problem may be with the internal contacts, such as the buttons or the battery connector terminals. It`s also possible that your car and remote unpaired from each other after you took the batteries out.
Do I need to reprogram the key fob after changing the battery? Typically, you do not need to reprogram the key fob after changing the battery. However, if you`ve replaced not just the batteries but also some of the internal wiring and electronics, you may need to reprogram it by pairing it with your vehicle once again.
If your key fob isn`t working after replacing the batteries, you may need to reprogram it or check for loose buttons and broken battery terminals. If your remote key fob isn`t working and you`ve already replaced the battery, you may need to reprogram the key.
This usually happens because of low batteries, but shock can also cause the fob to lose its pairing. Most remotes can be reset, so check your car`s user manual for the resetting sequence. If resetting fails to solve the problem, the fob will need to be reprogrammed.
If your ECU controls the anti-theft system, disconnecting the battery may lock you out of your car. Like desktop computers and most other electronics, disconnecting the battery cable for a short period will not fully reset your ECU due to the residual power remaining in the circuits.
Turn the key backward two places to the Lock position, then wait three more minutes. When that has elapsed, try to start the car. There`s often a fuse associated with the immobilizer, and like all fuses, it can blow. Check the owner`s manual to locate the fuse and assess its condition.
If you lose a key, an Authorised Mazda Repairer will reset the electronic codes of your remaining keys and immobilizer system. Bring all the remaining keys to an Authorised Mazda Repairer to reset. Starting the vehicle with a key that has not been reset is not possible.
If the engine is shut off while the indicator light is flashing, you will not be able to restart it. Because the electronic codes are reset when the immobilizer system is repaired, the keys are needed. Make sure to bring all the keys to an Authorized Mazda Dealer so that they can be programmed.
This blinking red light can be referred to as the anti-theft or immobilization light. The anti-theft light indicates that you need your key to start the vehicle, and it also alerts any car thief that this vehicle has an anti-theft system.
Some Security Systems for Cars Will Drain the Battery

The wiring to the alarm on these systems goes directly to the battery, and they will slowly take away energy from the battery. Eventually, this can lead to the failure of the battery. It generally happens later in the life of a battery.

Battery Current Sensor Problems

Dirt and Debris: Dirt, debris, or corrosion on car batteries can penetrate into the sensor causing malfunctioning. This failure can lead to a number of electrical problems including no-start.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

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.

2005 Chrysler 300C changed battery and alternator. Car started, ran, and then battery light came on. Shut car off and wouldn’t start.
ANSWER : Hi. There is a couple of things that could be wrong here. The battery or alternator that was just installed could be defective. Theses parts need to be tested for proper operation. There also could be a fuse, fusible link, or wiring for the battery or charging system that is blown or broken causing the battery light to come on.

The codes that you have will cause the car to shut down, run rough, or not start at all. The crankshaft sensor and camshaft sensor should be replaced. I suggest having a certified technician from YourMechanic come diagnose the charging system and check engine codes to help you proceed with correct repairs.

My car will not start Intermittently. I purchased a new battery 2 weeks ago and yesterday the car wouldn’t start. Got a jump and
ANSWER : The issue you are having is probably due to an intermittent fault in the starter motor itself or a deficiency in the starter electrical circuit, for example a large voltage drop due to a poor ground or a high resistance connection. These issues can be readily diagnosed and resolved on a mobile basis if you request a hard starting diagnostic. If you request that diagnostic, the responding certified mechanic will get this resolved for you promptly. Based on Toyota’s Factory Service Manual, the battery should not be disconnected if the vehicle engine is running. The battery acts as a large resistive voltage sink and consequently taking the battery out of the circuit, while the alternator is still running, can create a voltage spike on the car’s electrical system which is not good for voltage sensitive components such as the engine computer. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Water was spilled in the trunk which soaked the car battery. Car won’t start now. Does water destroy a car battery?
ANSWER : Hi, thanks for writing in about the concern with the BMW 320i. If the battery was submerged in water then it’s completely possible for the battery to short out and die. Your friend will need to have the battery replaced. Also be sure to get all of the water out of the trunk. Have a certified technician, like one from YourMechanic, help you guys out if you need assistance with replacing the battery. Good luck.

New battery & fuel pump. Hours later car starts and shuts down 3X in a row. Finally it starts, 48 hours later, won’t start at all
ANSWER : Checking all the fuses was a good move. I would also want to put a scan tool on it and check for diagnostic trouble codes (DTCs) as well as seeing the data that the computer is seeing.

A fuel pressure test would be a good idea to verify correct pressure and so that you’d be able to eliminate that possibility. It should be 58psi on your Magnum.

I also recommend getting your battery tested (I know, it’s new, have it tested anyway) and be sure it’s charged to at least 75%. And yes, loose battery cable connections can result in electrical problems.

If you need some assistance with this, consider enlisting a certified mechanic who can perform the checks I’ve mentioned and diagnose your starting issue firsthand. The mechanic can then perform the necessary repairs once the problem has been isolated. Good luck.

Map sensor car won’t start up good ?
ANSWER : Your MAP sensor is an important input for your computer. It helps determine the load on the engine to calculate the correct amount of fuel to inject. It sometimes takes a few seconds for the vehicle to realize that the sensor is not producing a good signal.

At that point, it will use other methods to determine the fuel rate, such as pre-programmed fuel maps, throttle position, etc. I would suggest replacing the MAP sensor and retesting. If you would like to have it checked first, a certified technician from YourMechanic will be able to scan your vehicle and test components to determine the root cause of your starting issue before making a repair.

The car crank but won’t start
ANSWER : Hi there. This does sound like an issue with the wiring. If the check engine light is coming on every now and then this means that when it does not come on there is no power to the computer. This can be the wiring harness issue or an ignition switch problem. I would have to test for voltage to the computer when the problem is occurring to be able to find where the issue lies. If you need assistance, a certified YourMechanic technician can be dispatched to your location to inspect your vehicle’s non-start issue and suggest any necessary repairs.

I have changed battery. I think I put non compatible battery initially and it’s start car alarm loud not turned off with remote ac
ANSWER : As long as the nominal voltage of the battery is 12 volts, it’s compatible. Of course, you need sufficient energy storage capacity, too, which in your case is probably around 850 cold cranking amps. As long as you did not reverse the positive and negative terminals (reverse polarity) when you installed the first battery, the battery is not incompatible. When new batteries are installed, inasmuch as any computer settings are lost, there can appear to be electrical problems, but such are not a fault of the battery. If, for example, you are having problems with the engine immobilizer system (security system) you may see a security warning light on the dash. If the warning light is on, to temporarily override the immobilizer system, see these instructions.

If you are experiencing electrical problems with other components, please simply request an electrical system diagnostic 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.