### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Worn catalytic converter [1]
– Recommended Fixes:
Replace catalytic converter https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Faulty MAF sensor
– Troubleshooting Process:
Inspect injectors [1][7]
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## Vehicle Service Vocabulary
### Skid Prevention Technology
– Function: Enables safe braking [7]
### Engine Management Unit
– Responsibility: Controls ignition timing [7]
### Drivetrain Components
– Includes: Differential [7]
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## Mechanical Fixing Workflow
1. **Initial Diagnosis**:
Scan DTCs
2. **System Verification**:
Test continuity
3. **Component Installation**:
Follow torque specs
4. **Final Quality Check**:
Confirm warning light reset
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## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | BlueDriver | Retrieve DTCs |
| Mechanical Tools | Smoke machine | Electrical testing |
—
## Service Information References
### Auto Repair Source
– Capabilities:
TSB access [8]
Factory repair procedures
### Mobile Applications
– Vehicle Service App:
ECU pinouts [5]
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## Affordable Maintenance Advice
– Routine checkups prevents major failures
– Understand DTC meanings to avoid unnecessary repairs
– Select certified components when OEM prices prohibitive [7]