### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Worn catalytic converter [1]
– Common Solutions:
Repair exhaust system https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Possible Defects:
Vacuum leaks
– Diagnostic Steps:
Inspect injectors [1][7]
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## Auto Repair Terminology
### Skid Prevention Technology
– Function: Enables safe braking [7]
### ECM/ECU (Engine Control Module)
– Role: Controls ignition timing [7]
### Powertrain Elements
– Contains: Drive axles [7]
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## Mechanical Fixing Workflow
1. **Symptom Assessment**:
Scan DTCs
2. **Component Testing**:
Check voltage
3. **Parts Replacement**:
Clear error codes
4. **Final Quality Check**:
Test drive vehicle
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Diagnostic Scanner | Autel | Live data streaming |
| Mechanical Tools | Smoke machine | Component repair |
—
## Service Information References
### Auto Repair Source
– Features:
Component locations [8]
Factory repair procedures
### Digital Assistants
– Vehicle Service App:
ECU pinouts [5]
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## Affordable Maintenance Advice
– Routine checkups avoids costly repairs
– Master code scanning to prevent mechanic overselling
– Install quality alternatives when OEM prices prohibitive [7]
