FreightViking is reader-supported. We may earn commissions if you buy through our links. Also, as an Amazon Associate we earn from qualifying purchases.

Volvo Truck Sensor Problems: 5 Common Faults & Fixes!

The sensors serve an essential function in trucks and semi-trucks. It helps you quickly monitor and detect several problems in your vehicle, such as temperature, pressure, vibrations, and more.

This way, you can detect issues and conduct immediate maintenance when necessary.

Volvo trucks are equipped with all the essential sensors for a safe drive. But these sensors may also need repairs for them to provide you with accurate readings.

This article discusses common Volvo Truck sensor problems and how to fix them.

A short summary of Common Volvo Truck Sensor Problems to Expect:

The most common Volvo truck sensor problems encountered are faulty instrument clusters, speed sensors, throttle position sensors, NOx sensors, and VEC sensors. These sensors monitor the truck’s status and health and must be fixed immediately when they are found to be defective.

Volvo Truck Instrument Cluster Problems

The instrument cluster is where you can find the essential displays and indicators when driving. 

It has several gauges: the speedometer, fuel gauge, oil pressure gauge, odometer, tachometer, and warning lights for system malfunctions.

Here are the symptoms you may notice if you have a broken instrument cluster on your Volvo truck:

  • Blinking lights
  • Defective turn signal indicators
  • Dim lights
  • Failure of the warning signals to turn off when you open the door and you have the key inserted in the ignition
  • Inaccurate gauge reading
  • Intermittent gauge failure

If you continue driving even with these signs, you risk your safety and the safety of other motorists you will also encounter on the road.

One way to determine if the instrument cluster is indeed failing is to diagnose it. Here’s how:

  1. Open the hood of your truck and find the fuse box.
  2. Check if each fuse is correctly connected with the instrument cluster.
  3. Search for possible damages such as broken wires or the soot in the fuse.
  4. If you see a broken fuse, you must replace it.
  5. If you still encounter problems, it is probably not the fuse but the wirings connected to the cluster. If similar issues persist, you can conclude that the instrument cluster is indeed the problem.

Volvo Truck Instrument Cluster Programming

Programming the instrument cluster of your Volvo truck may be the key to making it work properly.

Volvo now features Driver Display Activation on their vehicle’s remote programming system. 

With this, it is easier to tell when the next update will be. An icon will flash on the instrument cluster screen, telling you to conduct the update as soon as possible.

Software updates on your instrument cluster will enhance your truck’s uptime and performance. It will also allow you to lessen operation disruptions and change parameters on your vehicle.

Volvo Truck Dashboard Gauges Meaning

Dashboard gauges show the essential data you need to keep you aware of how your truck and its parts function.

The most common dashboard gauge you will find in a Volvo truck and also in other tracks are:

  • Air pressure: It measures the PSI of your truck reservoir. If you see that the air pressure in your truck is going below 90, there may be a leak in the air brake system. You should immediately pull over if driving when it happens to prevent a possible accident.
  • Engine oil pressure: It monitors your vehicle’s oil pressure. A truck’s average oil pressure is between 30 to 70 pounds per square inch (PSI). You should maintain the oil pressure level in this amount to prevent engine damage.
  • Fuel gauge: It tells you if you still have plenty of diesel in your tank and if it will last to reach your destination.
  • The odometer shows your truck’s total mileage and your route’s data. By checking the odometer, you will know if your vehicle may need an oil change and other necessary maintenance related to mileage.
  • Speedometer: It shows you the current speed you use while driving. Most of the time, it comes together with the odometer.
  • Tachometer: It measures your truck engine’s revolution speed per minute 9RPM). Most diesel engines nowadays have lower RPMs and maximum peak torque.
  • Temperature gauges: You will see many temperature-related gauges on your truck’s dashboard. It includes the coolantengine oilpyrometerrear and forward axles, and transmission. Maintaining the appropriate temperature for each will ensure the best performance of your Volvo truck.
  • Voltmeter: It shows the battery charge status. It changes color to red to let you know the battery needs charging.

Aside from the gauges, you will also notice different dash lights or warning lights prompting your truck’s dashboard. It alerts you on the current status or condition of your vehicle. 

Volvo Truck Speedometer Not Working

While in the middle of a drive, you may notice that the speedometer rests at zero even though you accelerate.

Some of the most common reasons why the speedometer of your Volvo truck stops working are a faulty speed sensor, broken gear, damaged wiring, or a faulty engine control unit.

Since the speedometer and odometer are usually together, the odometer may also not work.

If the cause is a faulty speed sensor, it is beyond repair. The best option is to discard the broken speed sensor and replace it with a new one.

Volvo Truck Dash Lights Not Working

You should refrain from driving if you notice that some of the dash lights of your Volvo truck are not working.

The most common reason for faulty dash lights issues is a lousy alternator, blown a fuse, burned-out bulb, or dimmer switch.

Here’s how you can fix the dash lights:

  1. Check the wiring diagram of your Volvo truck and look for fuse #35. If it has 10 amps, the problem may fall into the dimmer switch, rheostat, or the wiring.
  2. Pry the fog switch and dimmer. Switch it out using a small screwdriver.
  3. Unplug the dimmer connector. 
  4. With a multimeter, check the correct electrical functions at the connector pins.
  5. Turn on the dash lights. If it turns on with the ignition to ACC or RUN, the dimmer switch is the culprit. Thus, you need to look for a replacement.

Volvo Truck Speed Sensor Problems

If you experience problems with your truck’s speed sensor, you cannot get an accurate reading of your speed and mileage.

Aside from erratic speedometer readings, there will also be problems with the transmission, disabled cruise control, and lack of torque converter clutch application.

The leading cause of speed sensor failure is an internal electrical fault, damaged sensor, and poor vehicle maintenance.

If you think electrical wirings are at fault, you can test or diagnose it using a voltmeter or oscilloscope.

Or better yet, seek your trusted mechanic for possible problems on the VSS, and they can conduct the immediate replacement.

Cracks and damages to the speed sensor are also common reasons. The plastic portion of the speed sensor can become brittle over time, especially if there is prolonged exposure to certain elements.

The magnetic portion of the sensor also gets worn out over time. Thus, replacing it with a new one is the best option.

Regular vehicle maintenance will prevent failure of the speed sensor and prolong its parts.

Volvo Truck Throttle Position Sensor Problems

Your Volvo truck throttle position functions as the human brain’s motor cortex, It controls the truck components to keep the engine running.

If your truck’s throttle position sensor (TPS) malfunctions, it can cause severe issues.

The signs you should always take note of are acceleration issues, unstable engine idle, unusual fuel consumption, and the warning lights.

The repair and the cost will depend on your truck’s model.

If the throttle is outside, meaning it is visible and accessible, the repair will only cause you $500 for the necessary parts or replacements and the labor.

If it is inaccessible and it is hard to disassemble, you may need to double the amount of the repair cost.

Volvo Truck NOx Sensor Problems

A NOx or nitrogen oxide sensor tells you the number of nitrogen oxides your truck produces. 

If the NOx sensor fails, you will most likely encounter multiple issues on the dashboard as it is linked to the SCR system.

There would be more problems if you left the NOx sensor unfixed.

The best way to repair it is by replacing it with a new one, which costs around $500 to $1,000.

You may also find cheaper deals with the same quality as the expensive or newer ones.

However, replacing the NOx sensor may not solve the main issue immediately. That is why you can also install a NOx emulator. 

Volvo Truck VEC Sensor Fault

The Volvo Enhanced Cruise or VEC sensor warns and assists you with the interactions with vehicles in the front and side of your Volvo truck.

If it malfunctions, your truck will stop sensing the vehicles nearby or show you the “Impact Alert” that signals you to brake or take evasive action.

To fix the problem with the VEC sensor, you can check its cable connections or test VECU from a different truck that does not have a VEC sensor. Reprogramming it is also the best solution.

As you fix every sensor problem with your Volvo truck, you can always ensure a safe ride.