### P0420 Catalyst System Efficiency Below Threshold
– Frequent Reasons:
Exhaust leaks [1]
– Recommended Fixes:
Replace catalytic converter https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Vacuum leaks
– Diagnostic Steps:
Inspect injectors [1][7]
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## Vehicle Service Vocabulary
### ABS (Anti-Lock Brake System)
– Purpose: Enables safe braking [7]
### Vehicle Computer System
– Responsibility: Manages fuel injection [7]
### Powertrain Elements
– Includes: Transmission [7]
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## Service Procedure Stages
1. **Symptom Assessment**:
Conduct road test
2. **Part Evaluation**:
Test continuity
3. **Defective Unit Swap**:
Use OEM parts
4. **System Validation**:
Test drive vehicle
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Innova | Retrieve DTCs |
| Physical Equipment | Multimeter | Component repair |
—
## Service Information References
### Auto Repair Source
– Features:
TSB access [8]
Technical illustrations
### Digital Assistants
– Auto Repair Documents:
Electrical diagrams [5]
—
## Affordable Maintenance Advice
– Preventative service avoids costly repairs
– Understand DTC meanings to avoid unnecessary repairs
– Install quality alternatives when budget constrained [7]