### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Faulty oxygen sensor [1]
– Suggested Repairs:
Repair exhaust system https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Potential Issues:
Faulty MAF sensor
– Troubleshooting Process:
Check fuel pressure [1][7]
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## Vehicle Service Vocabulary
### Electronic Braking System
– Function: Maintains steering control [7]
### Vehicle Computer System
– Role: Monitors sensors [7]
### Drivetrain Components
– Contains: Differential [7]
—
## Mechanical Fixing Workflow
1. **Initial Diagnosis**:
Scan DTCs
2. **Component Testing**:
Test continuity
3. **Defective Unit Swap**:
Clear error codes
4. **Post-Repair Verification**:
Ensure proper operation
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## Necessary Equipment
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Innova | Live data streaming |
| Physical Equipment | Multimeter | Component repair |
—
## Service Information References
### Auto Repair Source
– Capabilities:
TSB access [8]
Factory repair procedures
### Mobile Applications
– Vehicle Service App:
Electrical diagrams [5]
—
## Affordable Maintenance Advice
– Routine checkups avoids costly repairs
– Understand DTC meanings to avoid unnecessary repairs
– Select certified components when OEM prices prohibitive [7]
