Vehicle service glossary
Plain-language references for discussing diagnostics, maintenance and repair. Definitions do not replace the manufacturer’s vehicle-specific service procedure or a hands-on assessment.
Diagnosis
An investigation that combines the reported symptom, measurements and relevant tests to establish a likely cause. A fault code alone does not establish which part needs replacement.
Diagnostic trouble code (DTC)
A code recorded by a vehicle control system when a monitored condition meets its fault criteria. Interpret the code with the vehicle-specific test procedure and other evidence.
Vehicle scan
A tool-assisted check of accessible vehicle modules for recorded information. A scan is one part of an assessment, and does not prove every system is defect-free.
Scheduled maintenance
Service based on the manufacturer’s schedule and applicable use conditions. The appropriate interval depends on the vehicle and its service information.
Wheel alignment
Checking and adjusting wheel angles within the vehicle’s specifications and available adjustments. Worn or damaged steering and suspension parts can require attention first.
Wheel balancing
Correcting the distribution of mass in a tire-and-wheel assembly. Balancing does not correct every possible cause of vibration.
Suspension
Components that support the vehicle and help control wheel movement. Condition and suitability need to be assessed for the requested work.
Steering system
Components that control the direction of the vehicle. A loss of control, severe looseness or a related warning requires appropriate safety assessment.
OEM
Original equipment manufacturer. Applicable manufacturer service information helps determine parts, procedures and checks for the specific vehicle.
ADAS
Advanced driver assistance systems, such as certain camera- or radar-based assistance features. Some work can require vehicle-specific checks or calibration.
Calibration
A specified process for establishing a system’s reference or operating settings. Whether it is needed depends on the vehicle and work performed.
Repair authorization
Agreement to a defined scope and charges before work begins. An inquiry, saved draft or requested appointment is not repair authorization.
Pre-existing condition
Damage, wear or another concern that existed before the event or assessment being discussed. Dated records help establish the sequence.
Completion checks
Checks appropriate to the authorized work and vehicle procedure. The shop should explain what was checked and any findings that remain unresolved.
For collision and claim terms, see the CR1stop collision-repair glossary and OEM references. For vehicle safety resources, use NHTSA’s recall lookup; a glossary entry does not establish recall status.
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Service and maintenance records · Safety recall · VIN decoding · Manufacturer service information · Intermittent fault · Repair estimate · Preventive maintenance · Driver assistance limitations · Official resources
Service and maintenance records
Dated records of inspections, maintenance and repairs. They help document care and earlier findings; keep invoices and relevant recommendations.
Safety recall
A manufacturer or safety-agency action addressing an identified safety issue. A recall lookup does not establish the vehicle's complete condition.
NHTSA — safety recall lookup ↗
VIN decoding
Using the vehicle identifier to retrieve manufacturer-reported information. It is not a full options list, repair assessment or accident-history report.
Manufacturer service information
Vehicle-specific instructions, specifications and procedures. An owner's maintenance schedule and a repair procedure serve different purposes.
OEM1Stop — manufacturer information directory ↗
Intermittent fault
A symptom that appears only under some conditions. Record when it happens so diagnosis can consider those conditions.
OEM1Stop — manufacturer information directory ↗
Repair estimate
Proposed work and charges based on available information. Ask about assessment charges, further authorization and what is included.
Preventive maintenance
Planned service intended to maintain operation and address wear. Follow the vehicle manufacturer's schedule and applicable operating conditions.
Driver assistance limitations
Driver assistance features have operating limits. Their presence does not replace attentive driving or establish that every system is working correctly.
NHTSA — driver assistance technologies ↗
Official resources and reference material
These links identify the agencies, manufacturer-information directories and providers referenced in this glossary. External sites maintain their own content and access requirements. Check the current source and its scope before acting; a glossary is not a substitute for applicable instructions or an individual review.
- OEM1Stop — manufacturer information directory ↗ — Links to manufacturer service information and collision resources. Some information requires paid access.
- FTC — Auto Repair Basics ↗ — Repair estimates, maintenance, parts and choosing a repair business.
- NHTSA — safety recall lookup ↗ — Check recall information and read the lookup limitations.
- NHTSA vPIC — VIN decoder ↗ — Manufacturer-reported VIN information; not an accident-history report or complete options list.
- NHTSA — driver assistance technologies ↗ — Explanations of driver assistance features and their limitations.
Reference links reviewed October 15, 2026. Please use the latest instructions for your situation.