### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Exhaust leaks [1]
– Recommended Fixes:
Diagnose fuel trim https://carautorepair.site/
### P0171 Fuel Mixture Imbalance
– Possible Defects:
Vacuum leaks
– Troubleshooting Process:
Inspect injectors [1][7]
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## Auto Repair Terminology
### Skid Prevention Technology
– Purpose: Enables safe braking [7]
### Engine Management Unit
– Role: Manages fuel injection [7]
### Powertrain Elements
– Contains: Transmission [7]
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## Repair Process Steps
1. **Problem Identification**:
Perform visual inspection
2. **Component Testing**:
Check voltage
3. **Parts Replacement**:
Use OEM parts
4. **Final Quality Check**:
Test drive vehicle
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Diagnostic Scanner | BlueDriver | Live data streaming |
| Mechanical Tools | Multimeter | Electrical testing |
—
## Service Information References
### Mechanical Information System
– Capabilities:
TSB access [8]
Technical illustrations
### Smartphone Tools
– Auto Repair Documents:
Electrical diagrams [5]
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## Budget Repair Strategies
– Preventative service prevents major failures
– Understand DTC meanings to prevent mechanic overselling
– Use aftermarket parts when OEM prices prohibitive [7]