### P0420 Catalyst System Efficiency Below Threshold
– Common Causes:
Worn catalytic converter [1]
– Common Solutions:
Diagnose fuel trim https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Fuel delivery problems
– Diagnostic Steps:
Smoke test intake [1][7]
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## Auto Repair Terminology
### Electronic Braking System
– Purpose: Prevents wheel lockup [7]
### Engine Management Unit
– Responsibility: Monitors sensors [7]
### Drivetrain Components
– Contains: Transmission [7]
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## Repair Process Steps
1. **Problem Identification**:
Scan DTCs
2. **System Verification**:
Measure resistance
3. **Component Installation**:
Use OEM parts
4. **Final Quality Check**:
Confirm warning light reset
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## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Diagnostic Scanner | Autel | Retrieve DTCs |
| Physical Equipment | Multimeter | Electrical testing |
—
## Technical Data Resources
### Auto Repair Source
– Features:
Component locations [8]
Factory repair procedures
### Digital Assistants
– Auto Repair Documents:
Component testing guides [5]
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## Cost-Saving Tips
– Regular maintenance prevents major failures
– Understand DTC meanings to prevent mechanic overselling
– Select certified components when budget constrained [7]
