### P0420 Catalyst System Efficiency Below Threshold
– Frequent Reasons:
Worn catalytic converter [1]
– Suggested Repairs:
Replace catalytic converter https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Vacuum leaks
– Troubleshooting Process:
Inspect injectors [1][7]
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## Auto Repair Terminology
### ABS (Anti-Lock Brake System)
– Purpose: Enables safe braking [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Manages fuel injection [7]
### Powertrain Elements
– Contains: Drive axles [7]
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## Service Procedure Stages
1. **Symptom Assessment**:
Scan DTCs
2. **Component Testing**:
Check voltage
3. **Defective Unit Swap**:
Follow torque specs
4. **Final Quality Check**:
Test drive vehicle
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## Necessary Equipment
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | BlueDriver | Retrieve DTCs |
| Hand Instruments | Multimeter | Component repair |
—
## Repair Documentation Sources
### Vehicle Service Database
– Capabilities:
TSB access [8]
Technical illustrations
### Mobile Applications
– Vehicle Service App:
Electrical diagrams [5]
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## Budget Repair Strategies
– Routine checkups prevents major failures
– Understand DTC meanings to prevent mechanic overselling
– Use aftermarket parts when OEM prices prohibitive [7]
