### P0420 Catalyst System Efficiency Below Threshold
– Frequent Reasons:
Worn catalytic converter [1]
– Suggested Repairs:
Repair exhaust system https://carautorepair.site/
### P0171 System Too Lean
– Potential Issues:
Fuel delivery problems
– Testing Procedure:
Inspect injectors [1][7]
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## Vehicle Service Vocabulary
### Electronic Braking System
– Function: Prevents wheel lockup [7]
### Engine Management Unit
– Role: Manages fuel injection [7]
### Transmission System Parts
– Contains: Transmission [7]
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## Service Procedure Stages
1. **Symptom Assessment**:
Perform visual inspection
2. **Component Testing**:
Check voltage
3. **Parts Replacement**:
Clear error codes
4. **System Validation**:
Confirm warning light reset
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## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Autel | Retrieve DTCs |
| Mechanical Tools | Torque wrench | Component repair |
—
## Repair Documentation Sources
### Vehicle Service Database
– Features:
TSB access [8]
Technical illustrations
### Smartphone Tools
– Auto Repair Documents:
Component testing guides [5]
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## Cost-Saving Tips
– Preventative service prevents major failures
– Master code scanning to prevent mechanic overselling
– Use aftermarket parts when budget constrained [7]