Pre-Collision Assist Not Available: Causes & Solutions

Modern vehicles remain incredibly dependent on advanced driver-assistance systems (ADAS) to enhance their safety features. Pre-collision assist is one of the most critical components in this system.

However, having a “Pre-Collision Assist Not Available” warning on the dashboard is extremely annoying, and when left long, it could lead to more hazardous experiences.

In this guide, we will cover the listed causes, along with their solutions and preventive measures, to help ensure your system functions properly.

What Is Pre-Collision Assist?

It is a feature that uses sensors to detect anything in front of the car. If the driver doesn’t brake in time, the system will automatically apply the brakes.

Common Warning Message: “Pre-Collision Assist Not Available”

This message usually lights up the dashboard when the system becomes incapable of doing its job. It may be intermittent or constant and generally also turns off automatic emergency braking (AEB).

Main Causes of “Pre-Collision Assist Not Available”

1. Sensor Blockage or Obstruction

The most common reason for this error is blocked radar or camera sensors.

• Front bumper radar and windshield-mounted cameras can be blocked by:
  • Dirt, snow, or ice
  • Fog or heavy rain
  • Aftermarket accessories like bumper stickers or bull bars

Solution: Clean the front grille and windshield. Remove any external accessories blocking the sensors.

2. Misaligned Sensors After Repair or Collision

After servicing or accidents, the sensors might become misaligned or disoriented.

• This is the cause of the radar’s inability to detect and follow objects accurately.
• It may also trigger other ADAS-related errors like “Front Camera Not Calibrated.”

Solution: Get the system recalibrated at a dealership or certified auto repair shop with ADAS tools.

3. Low Battery Voltage or Battery Issues

A weak or failing battery can impact system performance.

• Low voltage can turn off specific modules to conserve power.
• It may occur in cold climates or after the car has been idle for long periods.

Solution: Test the battery voltage and replace it if the voltage is below 12.4V or the battery is more than 3–5 years old.

4. Software Glitches or Corrupt Firmware

Outdated or corrupted software can cause communication failures between the camera and radar modules.

Solution:

• Perform a system reset via the infotainment menu.
• Visit the dealership to update the PCM (Powertrain Control Module) or BCM (Body Control Module) firmware.

5. Windshield Replacement Without Recalibration

Modern windshields house forward-facing cameras. If replaced, they must be recalibrated.

Failure to recalibrate after replacement causes this alert.

Solution: Schedule a dynamic or static calibration with an ADAS-certified technician.

6. Faulty Radar or Camera Module

Over time, electronic modules may fail due to:

• Moisture ingress
• Manufacturing defects
• Electrical shorts

Solution:

• Run a diagnostic scan using OBD-II tools.
• Replace the faulty module (camera or radar).

7. Wiring Harness or Connector Damage

Damaged wiring harnesses, especially in the front bumper area, can cut communication between the modules.

Common causes:

• Rodent damage
• Collision impact
• Corrosion

Solution: Inspect and repair or replace damaged wiring and connectors.

8. Extreme Weather Conditions

Heavy rain, fog, or snow can sometimes interfere with the functioning of the sensors.

Solution:

• Wait until the weather improves.
• Keep sensors clean.
• Don’t rely solely on ADAS in adverse weather.

9. Towing or Off-Road Driving Mode

Some vehicles disable pre-collision assist when in tow mode or off-road mode.

Solution: Switch back to normal driving mode in your settings.

How to Diagnose Pre-Collision Assist Malfunction

Step-by-Step Diagnostic Guide:

1. Check the dashboard message for any related alerts (brake assist, lane keeping, etc.).
2. Perform a visual inspection of the front bumper and windshield areas.
3. Use an OBD-II scanner to obtain DTCs (Diagnostic Trouble Codes). Check battery health with a multimeter.
4. For calibration, ask your service provider if you have recently changed your windshield or made repairs.

Vehicles Most Affected by This Error

This issue is frequently reported in:

• Ford Models: Fusion, Escape, F-150, Edge, Explorer
• Toyota Models: Camry, Corolla, RAV4
• Honda Models: Accord, CR-V
• Mazda, Hyundai, and Kia also report occasional system faults

How to Fix Pre-Collision Assist Issues: 7 Practical Steps

The Pre-Collision Assist system is meant to enhance driver awareness, help prevent accidents, and reduce the impact of any that should occur. But, like every other technology, it, too, can fail. In such a case, if your vehicle’s system reads “Pre-Collision Assist Not Available,” here are the seven troubleshooting steps you will have to follow to bring it back online:

1. Restart Your Vehicle

A simple restart may do the trick. If it does not respond, turn the vehicle off and restart it; this could mean a temporary glitch or software hiccup has been cleared. Usually, that resolves the issue. Always run a diagnostic scan after resetting (see Step 5) to verify that everything is on track.

2. Check for Obstructions

The camera and sensors require thorough cleaning, especially on the windshield, the grille area, and near the rearview mirror. Dust or leaves can check the system’s line of sight. Clean off any debris from around the sensor.

3. Verify Sensor Alignment

Your sensors might be misaligned even though even if everything looks clean. Minor bumps, car washes, or repairs may cause misalignments. Misalignment can often produce a false warning or cause the system to cease to work. So, if in doubt, please get a technician to check the sensors and calibrate them.

4. Update the Software

Keep your vehicle software up to date. Manufacturers often roll out updates that enhance systems, including Pre-Collision Assist. If it has been a while since your last update, this could be your answer. Updates fix bugs and help the system run at its best.

5. Run a Diagnostic Scan

Have a diagnostic tool check the Pre-Collision Assist system for error codes, or have your mechanic do that. The scan will show if there is an issue with the module, sensors, fuses, or any other components. It’s one of the best methods of determining what could be going wrong.

6. Reset the System

If the Pre-Collision Assist system continues to malfunction, you should reset it. This may clear lingering issues like false alerts or problems with adaptive cruise control. Some makes and models allow you to do this through the settings onboard; another option may be to use a scan tool, while others may need a dealership visit.

7. Schedule Professional Service

If none of the solutions above have worked for you, take your car to a professional technician or a dealership. There could be more serious internal electrical or module issues needing professional expertise.

How to Reset Pre-Collision Assist System

In some cases, a manual reset might resolve the issue.

Hard Reset Method:

1. Turn the ignition off.
2. Disconnect the negative battery terminal for 15 minutes.
3. Reconnect and start the vehicle.
4. Drive forward for a few minutes to allow system re-initialization.

Note: This method doesn’t solve hardware or calibration issues.

Preventive Measures to Avoid Future Alerts

• Clean sensors regularly, especially in winter.
• Avoid using aftermarket bumper attachments.
• Ensure proper calibration after repairs or replacements.
• Keep battery voltage healthy.
• Use genuine replacement parts if modules need replacing.

When to Visit a Dealership

If the warning persists after cleaning and basic troubleshooting, or if you’re unable to reset it using an OBD-II tool, it’s time to visit a dealership.

Certified technicians can perform:

• ADAS recalibration
• Module firmware updates
• Wiring repairs
• Complete sensor diagnostics

Can You Drive With Pre-Collision Assist Not Available?

Contrary to popular belief, sensors and cameras are not always covered under the standard or extended warranty; these are usually cases in which accidental damage or aftermarket modification does not apply.

Is Pre-Collision Assist Covered Under Warranty?

Yes, components such as sensors and cameras are mostly covered under warranty and even extended warranties. Damage due to accidents or aftermarket modifications may not be.

Cost to Repair or Replace Pre-Collision Assist Components

Related Article: Is Car Insurance Worth It?

Conclusion

This alert ensures that the pre-collision assist is disabled, and it’s a nuisance since it’s a key safety feature that is meant to prevent accidents.

From sensor cleaning to system recalibration and running the software update, every step mentioned above ensures that you are always safe on the road. Regular checks and swift actions can save you very costly repairs and dangerous situations.