What is condition-based maintenance? How it works, tools and how to start

Fleet managers know that picking the optimal time to service a vehicle is crucial to successful operations. Traditional time-based maintenance schedules can lead to unnecessary work or missed problems, increasing the risk of breakdowns. Condition-based maintenance (CBM) is a more strategic approach, using real-time data to trigger service when components truly need it. 

This guide explains what condition-based maintenance is, how it works and why it matters for commercial fleets. You will also learn practical monitoring techniques, why you should move away from reactive fleet maintenance and how to build a CBM program that fits your fleet's needs. 

What is condition-based maintenance?

Condition-based maintenance is a maintenance strategy that monitors the actual condition of vehicles and equipment to determine when service is needed. Instead of servicing assets on a fixed schedule — such as every 5,000 miles or six months — CBM uses data from sensors to identify when components are worn out. 

The methodology here is simple: Perform maintenance only when it is needed. This reduces unnecessary service intervals and breakdowns. In fleet management, CBM might involve monitoring engine fault codes and oil life indicators, or using vibration analysis, thermal imaging or fluid testing to assess component lifespan. 

Condition-based maintenance vs. predictive maintenance

Though condition-based monitoring and predictive maintenance are often used interchangeably, they represent different levels of sophistication in maintenance strategy. Understanding the distinction can help fleet managers pick the best approach for their needs. 

The main difference between condition-based maintenance and predictive maintenance is their approach to equipment monitoring. CBM will tell you when something is currently wrong, while predictive maintenance forecasts when something will probably go wrong in the future. Most fleets start with CBM and move toward predictive capabilities as their data and analytics grow. 

Typical tech stack for CBM

Implementing condition-based maintenance does not require a big technology investment upfront. Most fleets start with basic fault code monitoring and expand their tracking over time. 

A typical CBM tech stack includes: 

• Telematics devices and vehicle data access: This is hardware that connects to the vehicle's onboard diagnostics port and captures engine data, fault codes, odometer readings and operating conditions. 
• Sensors: This includes OEM-installed or aftermarket sensors for tire pressure, brake wear, fluid levels, temperature and vibration. 
• Condition-based maintenance software or CMMS: Fleets may use either a dedicated condition-based maintenance program or CMMS to log service history, schedule work orders and track asset performance over time. 
• Alerting and reporting layer: This includes tools that trigger notifications when thresholds are crossed and provide dashboards for fleet management reporting. 
• Data governance basics: These processes ensure asset IDs, odometer integrity and consistent fault code mapping. 

How condition-based maintenance works 

Condition-based maintenance operates as a conditional loop: 

• Data flows from vehicles
• Rules evaluate that data against thresholds
• Alerts trigger maintenance actions 
• Feedback from completed work refines future decisions

Understanding each step in this process helps fleets effectively implement CBM. 

Step 1: Capture vehicle condition data  

Reliable, real-time fleet data is the foundation of any CBM program. Vehicles generate a wealth of information through onboard diagnostics, telematics devices and sensors, including: 

• Battery voltage
• Oil life percentage
• Tire pressure
• Coolant temperature

Step 2: Set thresholds and rules  

Raw data alone will not tell you when to act. Fleets must define thresholds and rules that translate condition signals into maintenance triggers. These thresholds should be set based on manufacturer recommendations, historical failure patterns and operational priorities.

For example, a rule might state: "Generate an alert when oil life drops below 10%" or "Flag a vehicle when engine temperatures exceed 220°F for more than five minutes."

Step 3: Trigger maintenance actions  

When a threshold is crossed, the system generates an alert and initiates a maintenance action. This might look like: 

• A notification for a fleet manager
• An automatic work order in a maintenance system 
• A driver alert to schedule service at the next available opportunity 

Alerts should include enough context — vehicle ID, fault code, current condition, recommended action — to help technicians diagnose and address the situation effectively. 

Step 4: Close the loop 

The final step is to capture what was done and feed that information back into the system. Doing this supports root cause analysis and warranty recovery. Make sure to record: 

• Completed maintenance
• Parts replaced
• Labor hours
• Any additional findings 

Over time, this feedback helps you refine thresholds, identify recurring issues and validate that your CBM rules are working as intended. 

Condition-based maintenance examples

Fleets use a variety of monitoring techniques to implement CBM. The right mix depends on vehicle type, operating conditions and the systems that drive the most downtime. Below are some common condition-based maintenance examples.

OBD and engine fault codes

On-board diagnostics (OBD) is a standard system built into most modern vehicles that generates and stores diagnostic trouble codes (DTCs). Fleet software and telematics tools can pull and log these codes to determine when any of these systems operate outside normal parameters, including: 

• Engine
• Transmission
• Emissions
• Other systems

Monitoring this information in real time allows fleets to address issues before they escalate into breakdowns.

Telematics-based usage signals

Telematics devices provide insight beyond fault codes, pulling data like: 

• Engine hours
• Idle time
• Harsh braking events
• Rapid acceleration
• Power take-off (PTO) usage

These signals help fleet managers identify vehicles that experience heavier use and might need more frequent servicing.

Oil analysis

Fleets often send oil samples to labs at regular intervals or use telematics data to flag abnormal engine behavior. Results can reveal bearing wear, coolant leaks or fuel dilution. Consider testing for: 

• Viscosity
• Wear metals
• Contamination 

Coolant analysis

Similar to oil analysis, coolant testing checks for additive depletion, pH levels and contamination. Because degraded coolant loses its ability to protect against corrosion and overheating, these tests act as engine-critical health exams. 

Vibration monitoring 

Accelerometers and vibration sensors detect abnormal movement in rotating equipment like driveshafts, wheel bearings and auxiliary components. Increased vibration often signals: 

• Misalignment
• Imbalance
• Bearing wear

Thermal monitoring 

Temperature sensors keep tabs on overheating patterns in the brakes, wheel ends and engine. Sustained high temperatures can indicate: 

• Dragging brakes
• Failing bearings
• Cooling system problems

Early detection is key to preventing damage and reducing the risk of fires or wheel-off events. 

Brake wear indicators and lining thickness checks

Electronic brake wear sensors or manual thickness measurements offer direct insight into brake condition. Monitoring brake health supports safety compliance and helps fleets avoid costly violations.

Tire pressure and temperature monitoring

Tire pressure monitoring systems (TPMS) alert fleets when tires are underinflated or overheated. This lowers the risk of a blowout and extends tire life. Maintaining proper pressure also improves fuel efficiency and reduces uneven wear. 

Battery health

Prevent no-start events by monitoring these battery health metrics: 

• Battery voltage
• Cranking performance
• Charge cycles

For electric vehicles, battery health monitoring tracks cell degradation, charge cycles and thermal management to optimize range and lifespan.

Visual inspections with standardized checklists 

Though not sensor-based, digital checklists and Driver Vehicle Inspection Reports (DVIRs) can also help capture condition data that feeds into CBM programs. Consistent, structured inspections provide early warning signs that sensors might miss — like fluid leaks, worn tire tread or body damage — so it is important that your drivers keep an eye out. 

Advantages of condition-based maintenance 

By servicing vehicles based on actual need instead of a fixed schedule, fleets can optimize maintenance spending and minimize disruptions caused by unplanned repairs. Other advantages of condition-based maintenance include: 

• Less unplanned downtime and fewer roadside events: CBM catches problems early — before they escalate into breakdowns — which also makes it much easier to schedule off-road equipment maintenance.
• Better parts planning and labor scheduling: When you know which components are approaching failure, you can order parts in advance and schedule technician time more efficiently. 
• Longer component life when appropriate: Time-based maintenance often replaces still-functioning parts, while CBM allows components to run longer when conditions prove they are performing well. 
• Improved compliance and inspection readiness: Fleets subject to DOT inspections or other regulatory oversights are better positioned to pass inspections and avoid costly violations or out-of-service orders. 
• Stronger warranty recovery and root cause tracking: Detailed condition data and service records make it easier to identify root causes of component failures and substantiate warranty claims. 
• More accurate maintenance budgeting: CBM provides visibility into fleet health trends, enabling finance teams to  forecast maintenance costs more reliably. 

How to get started with condition-based maintenance 

Building a condition-based maintenance program does not require replacing your entire maintenance system overnight. Start small, focus on high-impact systems and expand as you gain experience and data. 

Identify high-impact vehicle systems 

Not every component has to have conditional monitoring. Start with systems that drive the most cost, safety risks or downtime. For many fleets, that means prioritizing the components often associated with the most breakdowns or compliance issues, such as:  

• Engines
• Transmissions
• Brakes
• Tires

Once you identify the vehicle systems that need the most attention, review historical maintenance data to find: 

• Systems with the highest repair frequency or cost
• Components that cause the most unplanned downtime
• Safety-critical systems subject to regulatory inspection

Focusing on high-impact systems ensures your early CBM efforts deliver the greatest impact and measurable value — which gets you more support for broader implementation.

Audit your current data and processes 

Before you set up conditional monitoring, assess the data you have already captured and consider how maintenance decisions are being made. Review whether you have: 

• Telematics devices installed
• Fault codes logged
• Centralized maintenance history 

Look for gaps in data quality, asset tracking and work order documentation. If your odometer readings are unreliable or fault codes are not mapped to service actions, you will need to address those issues first to avoid building on a poor base. A CBM program is only as good as the data feeding it. 

Define rules and thresholds  

The next step is working with your technicians and equipment suppliers to establish thresholds and rules for each monitored system. Start conservatively using manufacturer recommendations, then adjust accordingly as you get real-world data. 

Document each step of your rules carefully. Clear documentation keeps everything consistent and makes it easier to train new staff or scale the program. 

Important questions to ask yourself include: 

• What condition triggers an alert? 
• What action should occur when the threshold is crossed? 
• Who is responsible for responding to the alert? 
• How quickly must action be taken? 

Align maintenance workflows  

Condition-based maintenance only functions properly if your workflow can respond to real-time alerts. Integrate your condition monitoring platform with your maintenance management system so alerts automatically generate work orders, assign tasks and track completion. 

Technicians should also have access to the original condition data that triggered each alert so they can diagnose and repair efficiently. 

If your current processes are manual or paper-based, consider investing in vehicle maintenance software that connects data capture, alerting and work order management in a single platform. 

Pilot before scaling  

Test your CBM program with a small subset of vehicles or a single high-priority system before rolling it out fleetwide. A pilot allows you to refine thresholds, troubleshoot and demonstrate stakeholder value without disrupting your entire system. 

Key metrics to track during the pilot include: 

• Number of alerts generated versus alerts that resulted in a service
• Reduction in unplanned downtime or roadside events
• Cost per vehicle compared to baseline
• Technician feedback on alert quality and actionability 

Use pilot results to adjust your approach, secure a budget for expansion and build a roadmap for fleetwide implementation. 

Turn vehicle data into smarter maintenance decisions

The real power of condition-based maintenance is its ability to turn raw vehicle data into actionable insights. As fleets mature their CBM programs, they often add capabilities like trend analysis, fleetwide benchmarking and integration with parts inventory systems for even greater optimization. 

Condition-based maintenance also delivers insights beyond component health, including opportunities for route optimization, driver coaching and vehicle replacement planning. This data is key to helping fleets transition from reactive repairs to a cost-effective maintenance strategy. 

Ready to implement condition-based maintenance in your fleet? Geotab's fleet maintenance solutions connect vehicle data, alerting and workflows in a single platform to support smarter decision-making.