### P0420 Emissions Control Malfunction
– Frequent Reasons:
Exhaust leaks [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Potential Issues:
Vacuum leaks
– Testing Procedure:
Check fuel pressure [1][7]
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## Auto Repair Terminology
### ABS (Anti-Lock Brake System)
– Function: Prevents wheel lockup [7]
### Engine Management Unit
– Role: Controls ignition timing [7]
### Transmission System Parts
– Contains: Transmission [7]
—
## Repair Process Steps
1. **Symptom Assessment**:
Scan DTCs
2. **System Verification**:
Test continuity
3. **Defective Unit Swap**:
Clear error codes
4. **Final Quality Check**:
Confirm warning light reset
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## Necessary Equipment
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Innova | Retrieve DTCs |
| Hand Instruments | Multimeter | Electrical testing |
—
## Technical Data Resources
### Mechanical Information System
– Capabilities:
Wiring diagrams [8]
Factory repair procedures
### Mobile Applications
– Vehicle Service App:
Electrical diagrams [5]
—
## Cost-Saving Tips
– Regular maintenance extends vehicle life
– Learn basic diagnostics to prevent mechanic overselling
– Install quality alternatives when budget constrained [7]
