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Performing leak diagnostics on a Chevrolet Cruze

In Automotive Diagnostics, Vehicle Fluids by HomeTowne Auto Repair & Tire

We don’t always know what we’re walking into when it comes to car leaks. 

Sometimes, leak diagnostics are cut and dry. At other moments, they can take automotive professionals down unexpected twists and turns.

It might appear as though one culprit is behind a leak, but further testing shows that it’s just a part of the problem or not involved at all.

What causes oil in a coolant reservoir?

The driver of a Chevrolet Cruze saw coolant leaking from the coolant reservoir.

We found oil in the coolant reservoir. Oil in a coolant reservoir could indicate an internal engine issue, such as a head gasket problem or a similar failure. 

When we added coolant to the reservoir, bubbling occurred. That would suggest that air or combustion gases were entering the cooling system, further hinting at gasket problems. 

The car passed the cylinder leak-down test and the combustion leak test. A combustion test can determine if there are exhaust gases in the coolant, which would confirm that the engine seals are failing or there are gasket breaches.

The reservoir cap was replaced, because we thought the old one wasn’t holding pressure and caused the coolant to overflow. However, the problem continued after the new cap was put in.

Is it a head gasket or oil cooler problem?

We left the cooling system pressurized at 18 PSI overnight. By morning, the pressure had dropped to 10 PSI.

When we took the Chevrolet Cruze for a test drive, it didn’t overheat and the fan operated as it should.

We ruled out problems with the head gasket and started looking into the engine oil cooler. It was determined that the oil cooler might be damaged, allowing oil to mix with the coolant and forcing pressure into the reservoir.

If there is an internal rupture, the pressure of the engine is higher than the pressure for the cooling system. That’s why there was oil in the reservoir.

After the oil cooler and exhaust gasket were replaced, the coolant temperature went up but the radiator hoses were cold. Coolant wasn’t circulating in the system.

The technicians installed a new water pump, cleaned the radiator hoses and thermostat housing, and performed multiple coolant fluid exchanges.

How do we diagnose oil leaks?

Not all leak diagnostics are this complex. However, tracking down the cause can involve multiple steps.

Our process is determined by the type of leak a vehicle has. 

When looking into oil leaks, we degrease and clean everything off. Then, we add ultraviolet dye to trace the leak.

Performing a block test on a Chevrolet Cruze.
Performing a block test on a Chevrolet Cruze

How do we perform leak diagnostics on the cooling system

The avenues we go down for coolant leaks depend on whether the leak is external or if coolant is going into other systems.

Our technicians begin with a visual inspection. Then, they conduct a pressure test, which encourages any external leaks to appear.

If there is a loss of coolant but no external leak, we perform tests, such as the block test.

A block test (also known as a “hydrocarbon test”) is a way to see if the cylinder head has been compromised. What we’re looking for is combustion fumes in the cooling system that would indicate a cracked block or leaking head gasket.

Based on what we learn from the tests performed, we should be able to identify which parts need to be replaced.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dumfries, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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How did an AC compressor problem cause a car to shut off?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Did you know that problems with your air conditioning system could impact how your car operates?

We saw this occur with a Nissan Rogue. The SUV was brought to our shop because it experienced a number of issues all at once.

When the driver was at a stoplight, they heard a crackling noise. Then, lights started coming on the dash and the vehicle cut off.

Why did a Nissan Rogue shut off at a stoplight?

Through diagnostic testing, one of our technicians learned that the air conditioning compressor was locking up, causing the engine to stall.

Why did this happen? Well, sometimes, when something is wrong with one component, it can have a domino effect.

On certain vehicles, the drive belt (also known as a serpentine belt), wraps around and runs the compressor. It also surrounds other parts, such as the alternator and water pump.

A compressor that locks up can create an additional load, which impacts the engine’s ability to operate at idle.

We recommended a new compressor, an air conditioning condenser with a dryer, and an expansion valve. While replacing these components, the technician installed a new belt and tensioners. The a/c lines were flushed, as well.

A/C Condenser and Receiver Drier Assembly.
A/C Condenser and Receiver Drier Assembly.

What is a compressor in a car?

The a/c compressor is one of several items in a car’s air conditioning system. The compressor is responsible for creating pressure.

How do I tell if my car AC compressor is bad?

If you have a bad compressor, the a/c wouldn’t work. You’ll still feel air blowing, but it won’t be cold.

The compressor can either electrically break down or experience an internal mechanical failure.

To confirm that the air conditioning compressor is bad, we test it to see if it’s working. Our technicians would send power and ground to make sure it’s getting power. 

A bad compressor won’t turn on and the clutch won’t engage.

How to tell if a compressor is locked up?

When a compressor locks up, you would hear a noise and either the belt breaks or it doesn’t. 

A locked up compressor will affect everything else that is on that assembly, such as the water pump and power steering (if the vehicle has hydraulic power steering). 

The cooling system can be impacted, too. If it’s bad enough, the vehicle could start to overheat, especially if the belt wasn’t on.

A car’s alternator might also experience problems, resulting in the battery light turning on.

If the belt breaks, drivers may notice a rubber smell.

Can you drive a car with a locked up AC compressor?

You might be able to drive your vehicle if the AC compressor locks up, but it depends on the setup. 

For some cars, the compressor is driven by an air conditioning belt. In this case, you just wouldn’t turn on the a/c system. You don’t have to have an AC belt on to drive a car. As long as nothing else is relying on that belt to turn, then it’s fine.

However, if the compressor locks up and it’s driven by the drive belt, eventually it will probably throw the belt.

In the case of the Nissan Rogue, the driver tried to start the vehicle at the light, but it kept stalling. So, there wasn’t any time for the belt to break.

If you believe your a/c compressor has locked up and aren’t sure if it’s driven by an AC belt or drive belt, reach out to an automotive expert.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dale City, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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EVAP system problems: Why won’t my car let me fill it with gas?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Are you having trouble at the gas pump?

In rare cases, a car won’t let their driver fill it with gas.

Why is my Ford Fusion’s gas tank not filling up all the way?

We don’t often run across a car that won’t fill up with gas. However, this uncommon problem did occur on a Ford Fusion. Every once in a while, the driver couldn’t fill the tank up – whether it was close to empty or at half a tank.

Our technician didn’t find any codes in the scan tool. He confirmed the purge valve and vent valve were functioning and made sure the EVAP hoses and fuel filler neck weren’t clogged.

Using artificial vapor and a smoke machine, we are able to check for flow or a lack of it.

The fuel vapor canister was a little clogged. When we cleared it, it became unstuck.

We recommended filling the Ford Fusion with gas again to see if the issue continued. If it did, we would want to start by replacing the canister.

Fuel vapor canister on Ford Fusion.
Fuel vapor canister on Ford Fusion

What are reasons why a car won’t fill up with gas?

These are some items that could be behind a car to not fill up with gas:

  • Fuel vapor canister
  • Gas pump
  • Purge valve 
  • Vent valve

The purge valve and the vent valve all play a role. However, there is a filter inside the canister that gets clogged. The pressures of the vapor that are supposed to come up may not. 

On older cars, sometimes the flap won’t open up where the gas goes into the tank. The fuel pump has a big part to play, too. 

How do we figure out why a gas tank isn’t filling up?

Evaporative Emission Control (EVAP) systems are tricky. They aren’t always as cut and dry as other car problems, such as engine misfires.

We start our diagnostics process by collecting some background information from the driver.

One question we ask customers when they say the gas tank won’t fill all the way up is, “Have you tried another gas pump?” Because pumps have regulating factors in them to shut themselves off. So, the gas pump and the car work together to measure pressure.

If a driver says, “I tried two different pumps and it did the same thing,” we verify that the access to the tank is free. 

Then, we confirm that all of the vapor canister components are working correctly. There are two or three different things that can play a factor in the gas tank not filling up.

What are common EVAP system problems?

A car not letting you fill it with gas isn’t the only issue you may experience.

Some common EVAP system problems include the smell of gas, any EVAP leaks in the plumbing, and the purge of pressure.

Certain symptoms can appear when there’s something wrong with the EVAP system, such as the check engine light coming on and a vehicle running rough at idle.

If you are experiencing any EVAP system problems – the car not filling up with gas, performance problems, warning lights, or abnormal smells – you will want to bring it to a trustworthy auto repair shop for diagnostic testing.

They will be able to have the knowledge and tools to track down what’s causing the issue.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dumfries, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Why do I hear a roaring noise while driving?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Your vehicle can produce a variety of sounds. 

They may be noticed in different scenarios – like when you’re turning, braking, going over bumps, or driving at a certain speed.

A roaring noise is one sound drivers might notice.

Why does my car make a roaring noise?

There are few possible reasons why a car is making a roaring noise:

  • Hub bearing going bad
  • Tire wear
  • Brake problems
  • Worn differential bearing or transmission bearing

A roaring sound may be heard if it’s time to replace a hub bearing. Occasionally, the symptom could indicate that a bearing from the transmission or differential is worn.

Tires can create a roaring if there is cupping, feathering or any irregularity in the tread.

You might notice a roaring noise if there’s rust on the brake rotor surface.

What caused a roaring noise on an Acura?

Noise diagnostics was performed on an Acura RDX.

The driver could hear a loud sound coming from the wheels or tires at low speeds.

Our technician noticed a roaring noise and realized it was coming from a hub bearing. He recommended replacing the bearing as well as the rim, which was bent and wobbling.

What does a hub bearing do?

If you haven’t worked on vehicles or aren’t familiar with how they are set up, you may be wondering, “What is a hub bearing?”

Hub bearings – sometimes called wheel bearings – can be found in the steering system.

A bearing goes into the hub, which is connected to the steering knuckle.

The anti-lock braking system (ABS), in many cases, is a part of the bearings. Using data from the ABS, the computer is able to learn the wheel speeds.

There are hub assemblies that consist of multiple parts, and hubs and bearings that come as separate pieces.

How do I know if I need a new hub bearing?

How do you know if you have a bad hub bearing? A bearing problem can cause several symptoms, such as:

ABS engaging: Every once in a while, there will be something wrong with the tone ring that’s found in the bearing. Injuries to the tone ring may cause the anti-lock braking system (ABS) to kick in.   

Roaring noise or growling sound: As we’ve already mentioned, you might hear a roaring noise when the hub bearing should be replaced. A hub bearing problem could also come across as a growling sound. 

Traction Control Light or ABS Light: It’s possible that the Traction Control Light and ABS Light will turn on, because the tone ring and ABS wheel speed sensor are in many newer bearings.

Vibration: A vibration could be associated with a bearing, too. Vibration would occur if a wheel is shaking due to a loose hub bearing.

Hub bearing replacement on Acura.
Hub bearing replacement on Acura

How long do bearings last?

There is no set amount of time that hub bearings last. Generally, bearings go bad after 100,000 miles, unless influenced otherwise. We’ve also seen vehicles with 400,000 miles that haven’t needed to replace them.

Hard driving, impacts and driving conditions can expedite the wear process. Salt and sand that’s spread on the road may cause corrosion to build up on car parts, including bearings.

How do you maintain hub bearings?

On older vehicles you used to be able to service hub bearings by greasing them. You can’t service the bearings for newer cars, because they’re sealed.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Engine misfire on a Mini Cooper

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

If your car isn’t performing like it usually does, it could be the victim of an engine misfire.

When a vehicle doesn’t have the correct amount of air and fuel, it can result in a misfire.

Some misfire symptoms include a car running rough or struggling to accelerate. You might notice the check engine light turn on, too.

Many culprits can lie behind engine misfires.

To name a few possibilities, there could be something wrong with a valve, a sensor problem, or parts that have become worn out.

The reason may not be discovered through a visual inspection. Sometimes, a little detective work is needed to find the cause.

What caused an engine misfire on a Mini Cooper?

A Mini Cooper was brought into our auto repair shop because the check engine light turned on and it felt as though it was misfiring.

When one of our technicians checked the spark plug on cylinder 3, it was wet with gas. 

Wet spark plug on Mini Cooper.
Wet spark plug on Mini Cooper

An engine misfire was found on cylinders 1 and 3, and we moved the ignition coils from cylinder 3 to cylinder 4 and from cylinder 1 to cylinder 2. The misfire went to cylinder 4 and stayed on cylinder 3. The spark plug on cylinder 3 was wet again.

We performed a compression test on all four cylinders, and they were around 170 pounds per square inch (PSI).

Using a camera to look into the cylinders, we saw that cylinders 3 and 4 were wet. The fuel injector wasn’t spraying properly, which was causing the misfire.

To solve the problem, we replaced the spark plugs, ignition coils and fuel injectors.

How do you fix a misfire?

If you think your car is misfiring, you will want to bring it to a trustworthy mechanic or autoshop for diagnostic testing.

How we fix misfires depends on the diagnostic. You have several components that can cause a car to misfire.

Codes are a starting point and will determine what we do to diagnose the vehicle.

A variety of tools may be used during this process, including scan tools and cameras.

If the problem is internal, cameras allow us to take a look at the pistons.

With multimeters, we can check for poor voltage to and from the computer and to and from the secondary ignition. This tool is also used to look into the fuel injectors.

Occasionally, we will use a node light that lights up when the ignition coil is working.

On rare occasions, we might need to focus on the mechanical side and look at the timing.

Is it OK to drive with a misfire?

No, you should not drive a vehicle that has an engine misfiring. 

If the problem is ignored, it may lead to additional repairs and unsafe driving situations. 

Engine misfires could cause damage to the internals of the motor and the catalytic converter. 

You also run the risk of your car stalling. Poor performance on the highway can be dangerous for drivers, their passengers, and others on the road.

When you’re not sure if it’s OK to drive a vehicle, pull over and contact an autoshop to see what they recommend.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Lake Ridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Engine diagnostics training held for HomeTowne Auto Repair

In Automotive Diagnostics, News by HomeTowne Auto Repair & Tire

Tracking down engine problems was covered in a recent class.

HomeTowne Auto Repair and Tire participated in an Advanced Engine Diagnostics training that was run by NAPA AutoTech.

Data is one of the topics discussed during the training.

The NAPA AutoTech representative showed what a compression stroke and the wave form for a good crankshaft sensor look like.

Engine diagnostics training.
Engine diagnostics training

The engine diagnostics process

Information from the engine diagnostics training can be helpful for both service advisors and technicians.

When talking to customers, front counter personnel are able to better explain next steps in the diagnostic process.

One of our Service Advisors learned about other ways to diagnose cars that might save time in the future.

Misfires and mass airflow sensors

This course showed newer technicians that there is a lot more to learn. 

One of the Apprentice Technicians found the topic of emissions and engine misfires interesting.

The discussion about mass air flow sensors also stood out to him. At this point, he doesn’t typically run into mass airflow sensor problems, but it helped point him in the right direction when he works on them in the future

For more experienced technicians, the engine diagnostics training reaffirmed details they were aware of.

With regular training, our goal is to provide team members at all levels the support and knowledge they need.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Lake Ridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Is my AC compressor clutch going bad?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Some of our technicians have been working in the automotive industry for many years, and they still encounter new problems.

A unique issue was discovered on a GMC Terrain. Our customer brought the SUV in because they could hear a screeching noise while driving. This sound was coming from the passenger side and would get progressively louder as they were changing gears.

So began the diagnostic testing process.

How did we find the source of the screeching noise?

The noise was very noticeable when our technician started working on the GMC Terrain.

When the serpentine belt was taken off, the sound went away. So, he knew the problem had something to do with the air conditioning compressor.

The compressor creates pressure in the air conditioning system, compressing the refrigerant.

After removing the belt, the technician realized the clutch on the AC compressor was damaged and determined that it had failed.

We replaced the compressor and the serpentine belt. This belt wraps around your accessories, such as the alternator, compressor and – if the car has hydraulic power steering – the power steering pump. It’s a good idea to replace it while we’re there.

Diagnostic testing will look differently for each car. It can include visual inspections, test drives, receiving assistance from tools, and using the process of elimination to track down the culprit.

AC compressor replacement on GMC Terrain.
AC compressor replacement on GMC Terrain

What AC compressor problems can occur?

The problem we saw on the GMC Terrain isn’t a common one. In fact, our technician hasn’t seen it happen before. 

AC compressor clutches engage the pulley to the compressor. 

They could go bad, but normally because they wear out. The clutch coil may burn out, keeping it from engaging or unengaging.

An internal compressor problem is also possible. The compressor can get dragged down or locked up, or it might become worn enough that it doesn’t compress enough pressure.

How do I know if my AC compressor clutch is bad?

Like the GMC Terrain owner, drivers might notice symptoms when there’s a problem with the AC compressor or compressor clutch.

If the clutch coil is wearing out, it could engage or unengage sporadically. 

You can listen for noises, too. Sometimes, the air conditioning compressor or AC compressor clutch will start chattering. 

Air conditioning problems may also indicate that something is wrong with the compressor or clutch. (Keep in mind that a compressor going bad is just one of many possible causes behind car AC problems.)

If you’re hearing a sound you don’t recognize or a system isn’t working how it’s supposed to, it’s worth having the problem checked out. There may be an issue that worsens or impacts you later on. 

In the case of the GMC Terrain, our customer can now enjoy a quieter ride and expect to have a working air conditioning system come summertime.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dumfries, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Reasons behind windshield wiper problems

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

We have noticed a lot of vehicles coming in with windshield wiper problems.

A wide range of issues can affect this area – from windshield wipers that need to be replaced to deeper concerns.

To maintain visibility, it’s important to have these concerns addressed early on – especially with the long nights of winter and the inclement weather this season may bring.

What can cause windshield wiper problems?

Many items can be culprits behind windshield wiper problems. These components include:

  • Windshield washer fluid
  • Windshield wipers
  • Fuses
  • Windshield wiper arm
  • Windshield washer nozzles
  • Switch control
  • Windshield washer pump
  • Control module
  • Windshield wiper motor
  • Hoses
  • Windshield wiper transmission

Why aren’t the windshield wipers clearing my windshield?

When driving along one day, you might go to clear the windshield of smudges but little or no windshield washer fluid comes out. Maybe the reservoir needs to be refilled, or there could be a leak.

Another factor to keep in mind is the temperature protection level of the fluid. If it doesn’t have a good temperature protection level, the windshield washer fluid can freeze in the reservoir and pump.

Torn windshield wipers on Honda CR-V.
Torn windshield wipers on Honda CR-V

Are your windshield wipers leaving streaks when they swipe across the windshield? Has an auto repair shop told you that one or multiple wiper blades are torn? It’s probably time for new windshield wipers.

When the wiper blades become worn, it may lead to squeaking or chattering sounds.

A chattering noise could also indicate that the windshield wiper arms aren’t using the right kind of pressure.

Why isn’t windshield washer fluid spraying out?

If no washer fluid is being released and you know there’s plenty of fluid in the system, the problem may lie with the windshield washer nozzles. They can get clogged or break.

A bad windshield washer pump is another potential reason why the windshield washer fluid might not be making it to the windshield. 

We recommended a new pump for a Hyundai Santa Fe. The washers weren’t working and the technician couldn’t hear the motor running.

Why aren’t my windshield wipers working?

Broken wiper motor.
Broken wiper motor

Sometimes, there’s a problem with the windshield wiper motor. This could prevent the windshield wipers from moving when you turn them on or spray washer fluid. 

The motor broke on a Mitsubishi Eclipse and needed to be replaced.

It’s also possible that something is wrong with the windshield wiper transmission or multiple parts. 

This was the case with a Lincoln Town Car, where the wipers only worked for one cycle, and a Chevrolet Malibu that had inoperable windshield wipers. After making sure the fuses and relays were working on the Malibu, we found that the transmission had fallen off of the motor. 

Both the Lincoln Town Car and Chevrolet Malibu needed a new wiper transmission and wiper motor.

If you’re hearing a clunking when the wipers are moving, it could be the wiper transmission linkage assembly.

How do we solve windshield wiper problems?

Diagnostic testing for windshield wiper problems begins with checking the signal from the switch to the motor. 

If the function of the switch works, we will make sure we’re getting continuity from the fuse panel. Our technicians also confirm that no fuses are blown. 

From there, we will test to the motor. Once we get to the motor, we can test voltage, amperage and basic linkage.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dale City, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Signs of sensor problems

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Are you sensing an issue with your car? The cause may be rooted in components that can be found in several systems – sensors.

Sensor problems are a common occurrence that impact all kinds of vehicles.

Your auto repair shop might recommend replacing a sensor when you bring your car in for maintenance or have someone look into a problem.

What do sensors do?

Sensors play their own special part in how cars operate.

Simply put – sensors are your readers. Vehicles are made up of many sensors, which pass on information to computers.

They can be found in the Tire Pressure Monitoring System (TPMS), fuel system, cooling system, anti-lock braking system (ABS), steering system, engine and other places. 

Certain cars come with brake pad wear sensors or cam sensors. Those that use Advanced Driver Assistance Systems (ADAS) may have back up sensors.

Sensors can provide you with a variety of feedback, including telling you if your tires are low, detecting objects that are behind a vehicle, sharing how quickly a wheel spins, and noting if a seat has an occupant. 

What can cause sensor problems?

Like other components, sensors can go bad and need to be replaced. 

This could be the result of normal wear and tear. However, there may be other problems at play.

They include fluids as well as connector problems. Broken or chafed wires and corrosion buildup are other possibilities.

ABS wheel speed sensors sit in the knuckle. Sometimes, you’ll think a sensor is bad when really corrosion is collecting on the wheel speed sensor, causing it to move away from the tone ring.

What are signs of a bad sensor?

How can you tell when you have a bad sensor? The short answer is warning lights.

Check engine light on a GMC Sierra
Check engine light on a GMC Sierra.

A lot of times, when sensors go bad, they trigger dashboard lights, such as:

  • ABS light
  • Airbag light
  • Check engine light
  • TPMS light
  • Traction control light

Most drivers will notice these lights. However, depending on the system and sensor, there are going to be different signs.

For example, crankshaft sensors might cause your car to stall or not start.

If something is wrong with a wheel speed sensor, the ABS light could turn on or the system may feel funny.

A bad occupant sensor is a possible culprit behind the airbag light.

The check engine light may appear if there are oxygen sensor issues. These sensors can throw off the fuel trim, as well.

Meanwhile, TPMS sensors with a bad battery or circuit board may prompt a TPMS light.

How do we diagnose sensor problems?

How do we figure out if there’s a sensor problem? Through diagnostic testing.

If a customer notices a light or that their vehicle doesn’t seem to be running right, we perform diagnostics to determine the cause.

We start with any observations a driver has noticed, like a dashboard light turning on or an abnormal driving condition.

This process includes a visual inspection and checking for any codes. Our technicians also complete test drives and use information provided by the driver to narrow down their search.

The exact steps we take when conducting diagnostic testing will differ among the warning lights and which road manners appear. 

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dumfries, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.

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Airbag light: Reasons why it turns on

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Your vehicle’s dashboard houses many warning lights. 

Some may be more familiar to drivers, like the check engine light or tire pressure monitoring system (TPMS) light. 

Others – such as the airbag light – might not appear as often. However, they are still worth paying attention to.

The airbag system is an important safety measure for motorists and those riding with them. If the airbag light illuminates, it can indicate that something isn’t optimal. 

Airbag light causes

How is the airbag system set up?

You have your airbag computer module and each airbag that deploys is called a module. The system is also made up of connectors, seat sensors, and seat belt buckles.

The good thing about airbag restraint systems is that the smallest flaw will trigger the airbag light.

Here are some hidden problems that can prompt the light to appear:

  • Bad occupant sensor
  • Problems with the airbag module
  • Airbag clock spring failing
  • A wire is broken
  • Seat belt buckle resistor going bad
  • Auxiliary battery
  • Connector issues
Nissan Murano airbag light flashing.
Nissan Murano airbag light flashing

The airbag light may show up if a sensor is malfunctioning. One of them is the occupant sensor, which caused the airbag light to start flashing on a Nissan Murano. This sensor was built into the lower cushion and seat control assembly.

It’s also possible that the seat belt buckle’s resistor has failed.

Another reason why the warning light turns on is that your vehicle needs a new airbag module due to water damage.

Problems might occur with the airbag clock spring, as well. This component connects the steering wheel and airbag. Sometimes, it can go bad.

Broken wires and the auxiliary battery on European vehicles are other culprits that may prompt the airbag light to come on.

The symbol doesn’t always mean that an item needs to be replaced. Even something getting underneath the seats could mess up a connector, and we just need to go in and clean it up.

Diagnosing airbag lights

If your airbag light appears, have an automotive professional make sure that all parts of this safety feature are working correctly.

What does this look like? Our airbag light diagnostic process begins with a code scan. 

The next step is making sure the battery, contacts and charging system are in good working order. If the airbag system notices that the voltage is bad or below what it should be, it’s going to trigger a problem because it doesn’t have the proper voltage to operate the system.

Depending on where the code leads us, we would go to that airbag component and check the power and ground at the connector. There is going to be a spec for ohms of resistance on the part. 

An airbag simulator can be plugged into that component if it’s accessible. If you plug the part into where the fault is and it goes away, then you’ve isolated the problem.

Diagnostics could mean a return visit for drivers. Sometimes, before going down the diagnostic testing trail we will clear the light and send customers on their way to see if it reappears.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Lake Ridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.