> ## Documentation Index
> Fetch the complete documentation index at: https://docs.steerai.autos/llms.txt
> Use this file to discover all available pages before exploring further.
# Mechanical Diagnostics API
> OBD-II integration and comprehensive mechanical health analysis
## POST /v1/inspections/mechanical
Perform comprehensive mechanical diagnostics using OBD-II data, sensor readings, and AI-powered analysis. Detect engine issues, transmission problems, brake wear, and more.
### Request
```bash theme={null}
curl -X POST "https://api.steerai.autos/v1/inspections/mechanical" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"vehicle_id": "veh_1234567890abcdef",
"obd_data": {
"dtcs": ["P0420", "P0171"],
"live_data": {
"engine_rpm": 850,
"coolant_temp": 92,
"intake_temp": 25,
"maf_rate": 3.2,
"throttle_position": 0,
"fuel_pressure": 380,
"o2_sensor_voltage": 0.45,
"timing_advance": 15
},
"freeze_frame": {
"P0420": {
"engine_rpm": 2800,
"vehicle_speed": 65,
"coolant_temp": 95
}
}
},
"test_results": {
"battery_voltage": 12.6,
"alternator_output": 14.2,
"brake_fluid_level": "ok",
"engine_oil_level": "ok",
"coolant_level": "ok",
"transmission_fluid": "ok"
},
"options": {
"include_recommendations": true,
"severity_threshold": "minor"
}
}'
```
### Request Body
| Field | Type | Required | Description |
| --------------------------------- | ------- | -------- | ---------------------------------------------------------------------------- |
| `vehicle_id` | string | Yes | Vehicle identifier |
| `obd_data` | object | Yes | OBD-II diagnostic data |
| `obd_data.dtcs` | array | No | Diagnostic trouble codes |
| `obd_data.live_data` | object | Yes | Real-time sensor readings |
| `test_results` | object | No | Manual inspection results |
| `options.include_recommendations` | boolean | No | Include repair recommendations (default: true) |
| `options.severity_threshold` | string | No | Minimum severity to report: `minor`, `moderate`, `severe` (default: `minor`) |
### Live Data Parameters
| Parameter | Unit | Description |
| ------------------- | ---- | ----------------------------- |
| `engine_rpm` | RPM | Engine revolutions per minute |
| `coolant_temp` | °C | Engine coolant temperature |
| `intake_temp` | °C | Intake air temperature |
| `maf_rate` | g/s | Mass air flow rate |
| `throttle_position` | % | Throttle position (0-100) |
| `fuel_pressure` | kPa | Fuel rail pressure |
| `o2_sensor_voltage` | V | Oxygen sensor voltage |
| `timing_advance` | ° | Ignition timing advance |
| `vehicle_speed` | km/h | Vehicle speed |
| `engine_load` | % | Calculated engine load |
### Response
```json theme={null}
{
"status": "success",
"data": {
"diagnostic_id": "mech_1234567890abcdef",
"vehicle_id": "veh_1234567890abcdef",
"status": "completed",
"created_at": "2024-01-15T11:00:00Z",
"completed_at": "2024-01-15T11:00:15Z",
"results": {
"overall_health": "fair",
"health_score": 6.8,
"confidence": 0.91,
"systems": [
{
"system": "engine",
"status": "needs_attention",
"health_score": 7.0,
"issues": [
{
"issue_id": "eng_cat_efficiency",
"component": "catalytic_converter",
"severity": "moderate",
"status": "active",
"description": "Catalytic converter efficiency below threshold",
"dtc": "P0420",
"confidence": 0.94,
"symptoms": [
"Reduced fuel efficiency",
"Failed emissions test possible",
"Check engine light on"
],
"recommended_action": "Replace catalytic converter",
"urgency": "medium",
"estimated_repair": {
"min": 800,
"max": 1500,
"currency": "USD",
"labor_hours": 2.5
}
},
{
"issue_id": "eng_fuel_trim",
"component": "fuel_system",
"severity": "minor",
"status": "active",
"description": "System running lean (Bank 1)",
"dtc": "P0171",
"confidence": 0.88,
"symptoms": [
"Rough idle",
"Slight hesitation on acceleration",
"Decreased fuel efficiency"
],
"possible_causes": [
"Vacuum leak",
"Dirty MAF sensor",
"Fuel filter restriction",
"Weak fuel pump"
],
"recommended_action": "Inspect for vacuum leaks, clean MAF sensor",
"urgency": "low",
"estimated_repair": {
"min": 150,
"max": 400,
"currency": "USD",
"labor_hours": 1.5
}
}
]
},
{
"system": "transmission",
"status": "good",
"health_score": 8.5,
"issues": []
},
{
"system": "brakes",
"status": "good",
"health_score": 8.2,
"issues": []
},
{
"system": "electrical",
"status": "good",
"health_score": 9.0,
"issues": [],
"notes": "Battery voltage and alternator output within normal range"
},
{
"system": "cooling",
"status": "good",
"health_score": 8.8,
"issues": []
},
{
"system": "emissions",
"status": "needs_attention",
"health_score": 6.5,
"issues": [
{
"issue_id": "emis_cat_001",
"component": "catalytic_converter",
"severity": "moderate",
"status": "active",
"description": "Emissions system efficiency degraded",
"recommended_action": "Replace catalytic converter to meet emissions standards"
}
]
}
],
"maintenance_schedule": {
"overdue": [],
"due_soon": [
{
"service": "engine_oil_change",
"miles_remaining": 1200,
"recommended_date": "2024-02-15"
}
],
"upcoming": [
{
"service": "tire_rotation",
"miles_remaining": 3500,
"recommended_date": "2024-04-01"
}
]
},
"summary": {
"total_issues": 2,
"by_severity": {
"minor": 1,
"moderate": 1,
"severe": 0,
"critical": 0
},
"by_urgency": {
"immediate": 0,
"high": 0,
"medium": 1,
"low": 1
},
"total_estimated_repair": {
"min": 950,
"max": 1900,
"currency": "USD"
},
"systems_affected": ["engine", "emissions"]
}
},
"reports": {
"pdf_url": "https://reports.steerai.autos/mech_1234567890abcdef.pdf",
"json_url": "https://api.steerai.autos/v1/inspections/mechanical/mech_1234567890abcdef/report"
}
},
"meta": {
"request_id": "req_mech_xyz789",
"processing_time": 15.123,
"diagnostic_protocols": ["OBD-II", "CAN", "AI_Analysis"]
}
}
```
### Response Fields
| Field | Type | Description |
| ------------------------ | ------ | ----------------------------------------------- |
| `diagnostic_id` | string | Unique diagnostic inspection identifier |
| `results.overall_health` | string | `excellent`, `good`, `fair`, `poor`, `critical` |
| `results.health_score` | float | Overall health score (0-10) |
| `systems[].system` | string | Vehicle system name |
| `systems[].status` | string | `good`, `needs_attention`, `critical` |
| `issues[].severity` | string | `minor`, `moderate`, `severe`, `critical` |
| `issues[].urgency` | string | `immediate`, `high`, `medium`, `low` |
| `issues[].dtc` | string | OBD-II diagnostic trouble code |
### Vehicle Systems
**Components Analyzed:**
• Engine performance and efficiency
• Fuel system and injectors
• Air intake and MAF sensor
• Ignition system and timing
• Oil pressure and condition
• Compression and cylinder health
**Components Analyzed:**
• Shifting performance
• Transmission fluid condition
• Clutch wear (manual)
• Torque converter (automatic)
• Gear ratios and synchronizers
• Electronic controls
**Components Analyzed:**
• Brake pad/shoe thickness
• Rotor/drum condition
• Brake fluid level and quality
• ABS functionality
• Brake pressure and response
• Electronic stability control
**Components Analyzed:**
• Battery voltage and health
• Alternator output
• Starter motor function
• Lighting systems
• Electronic control modules
• Sensor diagnostics
**Components Analyzed:**
• Coolant level and condition
• Radiator and hoses
• Water pump operation
• Thermostat function
• Cooling fan operation
• Temperature regulation
**Components Analyzed:**
• Catalytic converter efficiency
• Oxygen sensors
• EVAP system integrity
• EGR valve function
• PCV system
• Emissions compliance
### Common DTCs (Diagnostic Trouble Codes)
| Code | System | Description | Typical Cause |
| ----- | --------- | ----------------------------------- | -------------------------- |
| P0420 | Emissions | Catalyst efficiency below threshold | Failed catalytic converter |
| P0171 | Engine | System too lean (Bank 1) | Vacuum leak, dirty MAF |
| P0300 | Engine | Random/multiple cylinder misfire | Spark plugs, coils, fuel |
| P0401 | Emissions | EGR flow insufficient | Clogged EGR valve |
| P0456 | Emissions | EVAP small leak detected | Loose gas cap, leak |
| P0442 | Emissions | EVAP medium leak detected | Cracked hoses, purge valve |
### Error Responses
#### 400 Bad Request
```json theme={null}
{
"status": "error",
"error": {
"code": "INVALID_OBD_DATA",
"message": "OBD data format is invalid or incomplete",
"type": "validation_error",
"field": "obd_data.live_data"
}
}
```
#### 422 Unprocessable Entity
```json theme={null}
{
"status": "error",
"error": {
"code": "VEHICLE_NOT_OBD_COMPATIBLE",
"message": "Vehicle does not support OBD-II diagnostics (pre-1996 model)",
"type": "validation_error",
"details": {
"vehicle_year": 1994,
"minimum_year": 1996
}
}
}
```
### Integration with Hardware
**Compatible Devices**
• Bluetooth OBD-II adapters
• WiFi OBD-II adapters
• USB OBD-II readers
• Professional scan tools
• Mobile diagnostic apps
**Supported Protocols**
• ISO 15765-4 (CAN)
• ISO 14230-4 (KWP2000)
• ISO 9141-2
• SAE J1850 PWM
• SAE J1850 VPW
### DeepDiag Integration
For advanced diagnostics beyond OBD-II, integrate with **DeepDiag**, our comprehensive diagnostic platform:
```bash theme={null}
curl -X POST "https://api.steerai.autos/v1/inspections/deepdiag" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"vehicle_id": "veh_1234567890abcdef",
"diagnostic_level": "comprehensive",
"include_mechanical": true
}'
```
**Pro Tip:** Combine mechanical diagnostics with visual inspection for a complete vehicle assessment. Bundle both API calls for discounted pricing.
### Webhooks
```json theme={null}
{
"event": "mechanical_diagnostic.completed",
"timestamp": "2024-01-15T11:00:15Z",
"data": {
"diagnostic_id": "mech_1234567890abcdef",
"vehicle_id": "veh_1234567890abcdef",
"overall_health": "fair",
"health_score": 6.8,
"issues_found": 2,
"critical_issues": 0,
"report_url": "https://reports.steerai.autos/mech_1234567890abcdef.pdf"
}
}
```
### Best Practices
**Data Privacy:** OBD-II data may contain sensitive vehicle information. Ensure you have proper authorization before collecting and transmitting diagnostic data.
1. **Regular Diagnostics:** Run diagnostics every 3,000-5,000 miles for optimal monitoring
2. **Multiple Data Points:** Collect data under various conditions (idle, acceleration, highway)
3. **Baseline Establishment:** Create baseline readings for healthy vehicles
4. **Trend Analysis:** Monitor changes over time to predict failures
5. **Combine with Visual:** Use both mechanical and visual inspections for complete assessment