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Honda Odyssey Won’t Start – What Could Be Wrong?

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The Honda Odyssey is a go-to van for taking the family from point A to B. However, it won't start then it makes it challenging to get you and your crew to where you need to go, so what could be wrong? Not to worry, in this article, we lay out the possible culprits to this problem!

If your Honda Odyssey doesn't start, it could be due to the following:

  • Dead/Faulty Battery
  • Corroded Battery Terminals
  • Loose Battery Cables
  • Dead Key Fob Battery
  • Faulty Alternator
  • Blown Fuses
  • Bad Starter Motor
  • Bad Starter Solenoid
  • Failing Starter Relay
  • Faulty Fuel Pump
  • Bad Spark Plugs
  • Malfunctioning Immobilizer System
  • Clogged Fuel Filter
  • Clogged Air Filter

As you can see, there are several reasons as to why your Honda Odyssey won't start. However, there are ways to troubleshoot each of these common issues.

This article will discuss each of these mechanical components and why they would keep your Honda Odyssey from starting. In addition, we will take a look at how to know if your car has an anti-theft system, so read on!

A white colored Honda Odyssey parked under a bridge, Honda Odyssey Won't Start - What Could Be Wrong?

Honda Odyssey Won't Start - What Could Be Wrong?

Some of the cons of why your Honda Odyssey won't start are that this could get expensive. Another con is that one of these issues may not necessarily be easy to fix. So the next time it may happen, it could just turn out to be another issue altogether.

However, if you can identify the issue and take care of it, your Honda Odyssey should start right up without any problems! So, let's take a look at some of the more common issues that may prevent your van from starting.

A dark green colored Honda Odyssey displayed at a car show

Dead/Faulty Battery

The battery is one of the most common culprits in why cars won't start. When it is dead or faulty, your car will not be able to turn over, no matter how many times you try.

To test if the battery is the issue, try jumpstarting your car. If it starts up after being jumped, the battery is most likely the problem. However, if it still doesn't start, then it could be one of the other issues on this list.

Corroded Battery Terminals

If your battery terminals are corroded, it will not allow a good connection between the battery and the car. This will prevent your car from starting.

Remove the battery cables and clean them with a wire brush to test if this is the issue. Make sure to remove any corrosion before reconnecting the cables. If this doesn't help, it may be time for a new battery.

Loose Battery Cables

To check if your battery cables are loose, locate them underneath your van's hood and make sure they are tight on the terminals. If one of your cables is loose, tighten it until you hear a click. This will ensure the cables are tightly fastened, which will prevent your car from not starting.

Dead Key Fob Battery

If the battery in your key fob is low or dead, then it won't send a signal to start your car. If this happens, try placing the key fob close to the ignition and see if it will start. If it doesn't, you may need to replace the battery in your key fob.

Faulty Alternator

If the alternator is bad, it will not produce enough electricity to start your car. To test if this is the problem, have a mechanic check the voltage of your battery. For example, if the battery is only putting out 10-12 volts, this may mean your alternator is bad.

Blown Fuses

If you have one or numerous blown fuses in your Honda Odyssey, it will cause issues when starting the car.

To check for this problem, locate your fuse box under the hood of your van. Then, check each fuse to see if it is blown. If so, replace the fuse with a new one of the same rating.

Bad Starter Motor

If the starter motor is bad, it will not start your car. To test if this is the issue, you will need to listen for a clicking noise when starting your car. In addition, the starter may make a grinding noise.

Faulty Starter Solenoid

If the solenoid is bad, it will not allow your car to start. The solenoid is responsible for sending power to the starter motor from the battery.

If you turn over the starter and hear nothing at all (not even a clicking sound), the starter solenoid could be the issue.

Failing Starter Relay

The starter relay is in charge of sending a signal from the ignition switch to the starter. So if you try to start the van and it won't start, but the starter is still making noise, it could be the starter relay.

Sometimes, the starter will still make a noise even after the key is out because the relay is trying to signal the starter from the battery.

Faulty Fuel Pump

If the fuel pump is bad, it will not supply gasoline to the engine. This will cause your car not to start.

To test if the fuel pump is bad, you can manually pump gas into the engine. After doing this, the fuel pump is most likely the problem if it starts up. In addition, the fuel pump will make a whining noise coming from the gas tank itself when its fails.

Bad Spark Plugs

If the spark plugs are bad, they will not create a spark necessary for the car to start.

To test if the spark plugs are bad, remove them and check the electrodes. If they are black and oily, this indicates that the plugs need to be replaced.

Malfunctioning Immobilizer System

If you notice that your car won't lock and unlock in addition to the Honda Odyssey not starting, it could be due to an issue with the immobilizer system. In addition, if you have a security light on the dash, it signals that the immobilizer is acting up.

Clogged Fuel Filter

If the fuel filter is clogged, it will not allow gasoline to flow through it, which will cause your car not to start.

To test if the fuel filter is clogged, remove it and check if there is any debris inside it. If there is, the fuel filter needs to be cleaned or replaced.

Clogged Air Filter

A car's air filter is responsible for trapping dirt, dust, and other debris before entering the engine. If the air filter is clogged, it will not allow the engine to get the proper amount of air which will cause the car not to start. If there is dirt inside of it, then you need to replace or clean it.

What does the green key light mean on a Honda Odyssey?

A green light key is a signal from the immobilizer. For example, if the green light key is on but flashing, it means that the immobilizer is functioning as intended. In addition, a green key light also signals that your car's security system is working correctly.

What is an immobilizer in Honda Odyssey?

The immobilizer is a security system that prevents your car from being stolen. It does this by emitting a signal to the vehicle, enabling it to start.

If a key is used to open the door or used to try and start the vehicle, then the immobilizer security system will detect it, keeping the van from starting.

A black colored Honda Odyssey moving fast on the highway

How do I bypass the Honda immobilizer?

What Honda you have will determine how to bypass the immobilizer system. For example, you will have to remove the immobilizer from the key socket itself on some Honda's. In other vehicles, you can perform a sequence of steps to disable the immobilizer.

For example, you can disconnect the negative battery terminal and reconnect it. This can reset the Honda's computer, returning it to factory settings. In addition, you can attempt to bypass the system by putting the driver key in the driver's door, unlocking it, locking it, and then unlocking it again.

The best thing to do is to call a Honda dealership and give them the VIN of your vehicle. They will do a system check on your vehicle and give you the next steps over the phone. 

How do you know if your car is in anti-theft mode?

You will know if your car has an anti-theft mode if there is a flashing security light when you try to start the vehicle. In addition, if there is a green key light on then, this typically means that your car is in anti-theft mode.

How do you reset the anti-theft system on a Honda Odyssey?

One of the most common methods to reset the anti-theft system is disconnecting the battery. Disconnecting the battery and then reconnecting it will reset the Odyssey's computer.

Another way to reset the anti-theft system is by using a computer program to clear the ECU. If you have one or can get to an automotive shop, this is a good option.

Lastly, locate the fuse box under the car's hood (black box). Once located, look at the diagram and remove the ECU fuse and "Back-up" fuse with pliers. Then wait 10 minutes or more before reinstalling the fuses.

Final Thoughts

A white colored Honda Odyssey parked under a bridge

It's not a fun situation to be in when your van doesn't start. However, you can diagnose some issues on your own by starting with simple components such as the battery and the battery cables. Once you feel overwhelmed, it is time to contact a certified mechanic that you trust for help.

If you like this article, then check out our other Honda Odyssey articles:

Honda Odyssey Won't Accelerate – What Could Be Wrong?

Honda Odyssey Not Recognizing Key – What To Do?

Honda Odyssey Door Not Closing: What To Do?