### P0420 Emissions Control Malfunction
– Common Causes:
Faulty oxygen sensor [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 Fuel Mixture Imbalance
– Possible Defects:
Faulty MAF sensor
– Testing Procedure:
Smoke test intake [1][7]
—
## Auto Repair Terminology
### Skid Prevention Technology
– Function: Maintains steering control [7]
### Engine Management Unit
– Responsibility: Manages fuel injection [7]
### Drivetrain Components
– Includes: Transmission [7]
—
## Service Procedure Stages
1. **Initial Diagnosis**:
Scan DTCs
2. **Component Testing**:
Test continuity
3. **Defective Unit Swap**:
Clear error codes
4. **Final Quality Check**:
Confirm warning light reset
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | BlueDriver | Live data streaming |
| Hand Instruments | Torque wrench | Electrical testing |
—
## Technical Data Resources
### Auto Repair Source
– Capabilities:
TSB access [8]
OEM specifications
### Mobile Applications
– Vehicle Service App:
ECU pinouts [5]
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## Cost-Saving Tips
– Regular maintenance prevents major failures
– Master code scanning to prevent mechanic overselling
– Select certified components when OEM prices prohibitive [7]
