How Much Does Car Diagnostic Test Cost?
Updated for 2026 — national average costs with state-by-state breakdowns
What Does Car Diagnostic Test Include?
A car diagnostic test uses a computer scanner to read trouble codes from your vehicle's onboard computer (OBD-II). It helps identify why your check engine light is on and what systems or components need attention.
The national average cost for car diagnostic test is $100 per diagnostic. Most homeowners pay between $50 and $200, though costs can vary significantly based on your location, the scope of work, and other factors outlined below.
What Affects the Price?
Level
Basic code read: $0-$50 (free at parts stores). Standard diagnostic: $50-$120. Advanced/dealer diagnostic: $100-$250
Shop Type
Parts store (free code read): $0. Independent: $50-$100. Dealership: $100-$200. Specialist shop: $75-$150
Complexity
Simple code (O2 sensor, gas cap): $50-$75. Electrical/intermittent issue: $100-$200. Multiple system diagnosis: $150-$250
Key Cost Factors
- ✓Shop type
- ✓Diagnostic depth (basic code read vs full analysis)
- ✓Vehicle make and model
- ✓Number of systems tested
- ✓Whether diagnostic fee is applied to repairs
💡 Tips to Save Money
- 1.AutoZone, O'Reilly, and Advance Auto Parts read check engine codes for free
- 2.Buy your own OBD-II scanner ($20-$50) for basic code reading
- 3.Many shops waive the diagnostic fee if you have the repair done there
- 4.Independent shops charge $50-$100 vs $100-$200 at dealerships for the same scan
📈 Car Diagnostic Test Cost Trends (2020–2024)
Prices have increased +19.0% over the last 5 years
| Year | National Avg | YoY Change |
|---|---|---|
| 2020 | $84 | — |
| 2021 | $88 | +4.8% |
| 2022 | $94 | +6.8% |
| 2023 | $97 | +3.2% |
| 2024 | $100 | +3.1% |
Based on national averages adjusted for annual inflation. Actual costs vary by location and project scope.
Car Diagnostic Test Cost by State
Costs vary significantly by state due to labor rates, cost of living, and local market conditions. Click any state for a detailed breakdown.
| State | Low | Average | High |
|---|---|---|---|
| Alabama | $41 | $82 | $164 |
| Alaska | $64 | $128 | $256 |
| Arizona | $48 | $95 | $190 |
| Arkansas | $40 | $80 | $160 |
| California | $68 | $135 | $270 |
| Colorado | $54 | $108 | $216 |
| Connecticut | $61 | $122 | $244 |
| Delaware | $53 | $105 | $210 |
| Florida | $49 | $98 | $196 |
| Georgia | $45 | $90 | $180 |
| Hawaii | $71 | $142 | $284 |
| Idaho | $46 | $92 | $184 |
| Illinois | $53 | $105 | $210 |
| Indiana | $44 | $88 | $176 |
| Iowa | $43 | $86 | $172 |
| Kansas | $43 | $85 | $170 |
| Kentucky | $42 | $84 | $168 |
| Louisiana | $44 | $87 | $174 |
| Maine | $51 | $102 | $204 |
| Maryland | $57 | $115 | $230 |
| Massachusetts | $65 | $130 | $260 |
| Michigan | $46 | $92 | $184 |
| Minnesota | $51 | $102 | $204 |
| Mississippi | $39 | $78 | $156 |
| Missouri | $44 | $87 | $174 |
| Montana | $48 | $95 | $190 |
| Nebraska | $44 | $88 | $176 |
| Nevada | $51 | $102 | $204 |
| New Hampshire | $56 | $112 | $224 |
| New Jersey | $63 | $125 | $250 |
| New Mexico | $45 | $90 | $180 |
| New York | $66 | $132 | $264 |
| North Carolina | $45 | $90 | $180 |
| North Dakota | $45 | $90 | $180 |
| Ohio | $45 | $90 | $180 |
| Oklahoma | $42 | $83 | $166 |
| Oregon | $55 | $110 | $220 |
| Pennsylvania | $51 | $102 | $204 |
| Rhode Island | $57 | $115 | $230 |
| South Carolina | $44 | $87 | $174 |
| South Dakota | $43 | $85 | $170 |
| Tennessee | $43 | $86 | $172 |
| Texas | $47 | $93 | $186 |
| Utah | $48 | $95 | $190 |
| Vermont | $54 | $108 | $216 |
| Virginia | $53 | $105 | $210 |
| Washington | $57 | $115 | $230 |
| West Virginia | $40 | $80 | $160 |
| Wisconsin | $47 | $94 | $188 |
| Wyoming | $46 | $92 | $184 |
Frequently Asked Questions
Is a check engine light urgent?
A steady check engine light means there's an issue that needs attention but isn't immediately dangerous. A flashing check engine light indicates a serious problem (usually engine misfire) — reduce speed and get it diagnosed immediately to prevent catalytic converter damage.
What's the difference between a code read and a diagnostic?
A code read ($0-$50) tells you WHAT code is stored (e.g., P0420). A proper diagnostic ($50-$200) tells you WHY — the technician tests specific components to identify the root cause. A code is a starting point, not a diagnosis.
🏙️ Car Diagnostic Test Cost by City
Compare car diagnostic test costs in the most popular US cities:
View all 219 cities →
Related Cost Guides
💬 What Did You Pay?
Real costs reported by homeowners for Car Diagnostic Test
Recent Reports
📐 Car Diagnostic Test Cost Calculator
Get a personalized estimate based on your project details
Get a Free Estimate
Compare costs and connect with providers in your area.
🔍 Get Auto Repair Estimates
Compare prices from trusted mechanics near you. See fair price ranges before you go.
* CostWhale may earn a commission. This doesn't affect our pricing data or recommendations.
💰 Get Weekly Cost-Saving Tips
Join 10,000+ smart homeowners. Unsubscribe anytime.