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Mazda Millenia: All Most Common Problems

What kind of problems does a Mazda Millenia normally have? In this blog we’ve outlined all the most important things you should keep an eye out for when you’re in the market for an Millenia. However, let’s first start of with a quick answer:

Most commonly the Mazda Millenia has rust problems at the rear of the car. Engine problems are also common and can be cause by a variety of parts including the fuel pump, sensors or fuel injectors. The supercharger has a short life span an can develop oil leaks. Finally, the electronics can malfunction and develop several issues.

However, that doesn’t tell the whole story. In the rest of the article we’ll discuss every single problem into detail. Furthermore, we’ll tell you how to identify it, how to fix it and how much it costs to fix. Read on!

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Also read: The Complete Cost Of Maintaining A Mazda

Exterior Problems

The Rear Of The Car Tends To Accumulate Rust

The rear side notoriously gets rusted, and it’s prominent across all the model years. The shape of the car contributes to the retention of moisture, especially when mud gets stuck around the side panels, and under the vehicle.

The rust can be removed DIY. The process includes:

  • cleaning the dirt and grease
  • grinding the rust
  • Spray primer on the exposed surface
  • Spray the paint of your choice
  • Protect the surface by spraying fluid film or WD-40

This procedure works great for the components under the vehicle, but the body panels outside will be mismatched because of the spray paint. However, the underside components can be painted black without a hitch. If you are okay with the mismatched paint on the outside then you are good to go.

Professional rust removal costs around $500, which can be even more depending on the overall condition of the vehicle. If you can do it DIY, you will be able to save a lot of money.

The Trunk Wouldn’t Open With The Button

One commonly occurring problem is with the trunk lid switch, it would fail to open with the press of a button and would require you to open the trunk manually. The problem lies behind the glove box compartment, inside the fuse box. A blown-up fuse there causes this problem with the trunk.

After changing the failed fuse, you will have the automatic trunk back in action. The fuse costs around $5. You just have to find it on the diagram given on the lid of the fuse box or use a voltmeter to know which one has died. 

Interior Problems

The seats are normally super comfortable, coupled with the smooth suspension. If you find the seats to be uncomfortable while the suspension doesn’t have any squeaking noises then you have to spend some money on reupholstering the seats as the seats do tend to flat out after some years of usage.

The cost of reupholstering varies a lot ($17.5-$250 per piece) and sometimes it might be even more than a new set of aftermarket seats, so make sure to find a good deal around you. But you can also go for some used ones in good condition.

Engine Problems

2001 is the worst year for engine problems. Make sure to listen to any weird noise coming from the engine. Note that clunking noises aren’t normal, if you hear any, then there is an issue. 

Cranks But Won’t Start

There are 7 main reasons why we experience this issue:

Fuel pump (most common): To check if you are having a fuel pump issue, you can try to hear the sound when the fuel pump initiates when you turn on the key all the way in but not giving a crank to the engine.

If you go to the rear side of the vehicle near the tire, you will hear that machine-like sound that indicates that the fuel pump is fine. If you don’t hear that sound then it means the fuel pump is the culprit. You can find a fuel pump for around $40.

Fuel pump fuse: Located in the fuse box inside the engine bay, top right corner. Open the plastic lid and you will see a separate section with elongated fuses having two screws. You can check if they are working by using a voltmeter. These fuses cost around $15

Fuel Pump Relay: If the fuel pump sound is heard then it clearly means that the relay is working fine. If the fuel pump sound is not heard then it will either be a relay problem or the fuel pump itself might be the problem. The price for this relay is around $5.

Fuel Injectors: Another fuel pump for pressure injecting the fuel. Check the connectors and the fuel injectors if they are properly connected and are in working condition. These injectors cost around $200 in the aftermarket. The factory ones are ridiculously expensive. You can have them replaced for around $400 including labor.

Fuel Injectors’ Relay: The fuel injector relay might also be the problem in which we have a crank but no ignition. Again this relay is located in the fuse box of the engine bay. The two big, similar components together are the relays, you can check them with your voltmeter. Costs around $5.

Fuel pressure sensor: If this sensor fails then we face the same issue of the crank but no start. It is priced at about $15.

Fuse for ignition coil/ignition key/ECM/ECT: This fuse might also blow up causing the problem in hand. You can have it replaced for about $5.

“A good fuse, when connected to both of the wires of the voltmeter, will show a zero reading, which means that this fuse works. If the voltmeter shows no connection, then we have a blown fuse. The diagram on the fuse box cover will also give you an insight into all the components.” 

EGR Valve Often Gets Clogged And Causes Poor Idle

If you are having a rough ride, one of the first things that might cause this problem is the clogged up EGR valve. These valves often accumulate carbon debris causing the poor flow of the gases inside the system. The cleaning of the EGR valve can cost around $150.

This phenomenon can impact the air and fuel ratio causing:

  • poor idle
  • poor acceleration
  • increased emissions
  • affecting the sensors
  • decreasing the fuel economy
  • Increased combustion temperature

SuperCharger Problems

The fuel consumption is a lot in these cars, even more with the supercharger attached. A new supercharger costs around $1200.

Life Span

Yes, you heard that right, this plain-looking car had a supercharger in its lineup. And consequently came related problems. This car is reliable indeed, but the supercharger might need replacement sometime soon after you buy it these days. They last (give and take) 10 years or so. You must include the price of the supercharger if it hasn’t been changed yet.

Oil Leaks

Because of the supercharger, we also experience some oil issues as well. These superchargers are known to have plenty of spills, and everyone knows, to get rid of these oil issues you just have to paint the engine in black, and no more oil leaks.

But that’s just a temporary fix, a permanent fix is to change the gaskets frequently, but they are super expensive to replace so If you are experiencing a lot of oil leaks then it is better to have a catch can. After installing, it can balance out the extra pressure and keep your oil clean, catching all the gunk from the system.

There are also some other ways to prevent the head gasket from leaking i.e using some block seal. Look it up, it will cost you a lot of bucks.

Rattling Noises Coming From The Supercharger

Any rattle coming from the supercharger is abnormal. It indicates that there is a problem with the supercharger. If you go for a rebuild, it will only last a little while then break down again. Only the signature supercharger sound is what you should hear. Any rattles or clunks are unacceptable.

Suspension Problems

They are very comfortable, if you feel that the ride is rough then you are definitely having some suspension failure. There can be a lot of different types of issues with the suspension if there are any.

Clunking Noise Is Heard When Going Over A Bump

While going over potholes, if you are hearing a clunking noise then it’s the consequence of either a ball joint failure or some worn-out mounts. It’s advised to check under the vehicle as well to ensure that everything is in working condition. Having the vehicle on a forklift is a must to thoroughly inspect the suspension components.

You can have the ball joints replaced for about $200.

Extremely Bumpy Ride

If you are experiencing a very rough ride that continuously makes the car vibrate while driving then you are having a strut/shock failure. With this failure, you would have to spend about $800-$900.

Tilting Too Much While Cornering

If the car feels as if it will roll over during turn then it means the sway bars are out and needs replacement. It will cost you about $100.

Electronics Problems


It’s a “Random misfire” code that causes rough idle. There could be several reasons why this could happen. First, pull the plugs out and see if they are worn out, orange current means it’s time to replace these ($80). After changing the plugs if the misfire issue persists then the ignition coils ($400-$500) are the culprit. Cylinders 6 and 3 are known to have misfiring issues.

Changing the Ignition coils will greatly increase the smoothness of your ride. If the problem still persists then the most likely cause is somewhere else.

The power steering can cause this poor idle, yes you heard that right. After some detective work, it seems that the cable from the power steering breaks and gets stuck between the camshaft and crankshaft, and we would face this timing jump phenomenon and experience the symptoms. It happens due to the way it’s designed and manufactured. 

Camshaft timing is the biggest problem; the timing belt and new tensioner can eradicate the problem at hand. But the cost is mind-boggling, more than $1000.

O2 Sensors Go Out A Lot

As discussed below, the O2 sensors fail due to carbon build-up in the exhaust manifold rendering the sensors incapable. The ECU consequently wouldn’t get the right reading and the air-fuel mixture will be improper, causing the system to run rich by throwing more air into the mixture and causing more carbon to build up.

The cost to replace these is $400 on average. The part itself only costs about $50, 2 of these will be around $100, the rest of the cost is the labor.

Engine Bogs Down And Loses Power

The most probable diagnosis would be the TCS (traction control system). But the actual problem lies somewhere else. The traction control module is affected as an aftermath of something else which is the root cause, and changing the TCS sensor wouldn’t make the light disappear and the engine would still cut off power.

The real problem is the vacuum hose leaking somewhere and should be diagnosed properly to find where the leak is. After replacing the affected hose, the engine bogging down and losing power will no longer happen again. It’s because of this vacuum leak, the ECU gets confused and the traction control gets affected and the power gets cut off.

The code that you might see during this particular issue is P1250.

Pesky Check Engine Light

The O2 sensors often get carbon debris that makes them incapable of giving the right information to the ECU, so the emissions standards are not met, the worst-case scenario, the mileage numbers drop as well with poor idle and misfires. The issue is caused mainly due to superchargers forcing more and more fuel to go into the system.

With more air comes more fuel covering the O2 sensors with a carbon coat and rendering them useless. So the check engine lights come to haunt you. There is an easy fix for this rather than going for the expensive and not necessary fix. Because even if you add a new convertor, the issue will not be resolved.

The downstream O2 sensors are known to get affected by this problem but instead of getting rid of the symptoms why not get rid of the cause?

The Actual Cause

On higher RPMs the oil seals of the engine and the pistons leak blow-by gases that enter into the exhaust manifold, blow-by is normal but in this case, it’s a lot, causing the sensitive O2 sensors to fail, and consequently, the check engine light illuminates your eyes.

So before getting a rebuild, it’s better to add “Sea Foam” into a full tank which will help clean the residue material off of the sensors and other essential components, just like giving your car a wash – but from the inside. The check engine light will go away. And it won’t harm your engine, it’s a highly refined petroleum that lubricates your entire fuel system.

For regular use, you can add one ounce per gallon and for cleaning purposes add more, the more the better. When the seafoam is added into a near-empty tank, the cleaning will be extraordinary. But it’s recommended to use lower amounts regularly, if a large chunk of debris is loosened up because of adding large amounts of seafoam, it may clog the fueling system.

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