### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Exhaust leaks [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 Fuel Mixture Imbalance
– Likely Problems:
Vacuum leaks
– Testing Procedure:
Check fuel pressure [1][7]
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## Car Maintenance Terms
### Electronic Braking System
– Purpose: Maintains steering control [7]
### ECM/ECU (Engine Control Module)
– Role: Manages fuel injection [7]
### Powertrain Elements
– Contains: Transmission [7]
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## Service Procedure Stages
1. **Initial Diagnosis**:
Scan DTCs
2. **System Verification**:
Check voltage
3. **Parts Replacement**:
Follow torque specs
4. **Final Quality Check**:
Confirm warning light reset
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## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | BlueDriver | Retrieve DTCs |
| Physical Equipment | Smoke machine | Component repair |
—
## Repair Documentation Sources
### Mechanical Information System
– Capabilities:
Wiring diagrams [8]
Factory repair procedures
### Digital Assistants
– Vehicle Service App:
Electrical diagrams [5]
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## Cost-Saving Tips
– Routine checkups avoids costly repairs
– Learn basic diagnostics to prevent mechanic overselling
– Install quality alternatives when budget constrained [7]
