### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Worn catalytic converter [1]
– Common Solutions:
Diagnose fuel trim https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Vacuum leaks
– Troubleshooting Process:
Smoke test intake [1][7]
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## Vehicle Service Vocabulary
### Skid Prevention Technology
– Function: Maintains steering control [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Controls ignition timing [7]
### Powertrain Elements
– Contains: Transmission [7]
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## Mechanical Fixing Workflow
1. **Symptom Assessment**:
Conduct road test
2. **Component Testing**:
Measure resistance
3. **Defective Unit Swap**:
Clear error codes
4. **Post-Repair Verification**:
Confirm warning light reset
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Diagnostic Scanner | BlueDriver | Retrieve DTCs |
| Physical Equipment | Smoke machine | Electrical testing |
—
## Repair Documentation Sources
### Mechanical Information System
– Features:
Component locations [8]
Factory repair procedures
### Smartphone Tools
– Auto Repair Documents:
Component testing guides [5]
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## Affordable Maintenance Advice
– Regular maintenance extends vehicle life
– Master code scanning to avoid unnecessary repairs
– Use aftermarket parts when OEM prices prohibitive [7]