### P0420 Emissions Control Malfunction

– Typical Sources:

Worn catalytic converter [1]

– Common Solutions:

Diagnose fuel trim https://carautorepair.site/

### P0171 Air-Fuel Ratio Error

– Potential Issues:

Faulty MAF sensor

– Testing Procedure:

Smoke test intake [1][7]

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## Auto Repair Terminology

### ABS (Anti-Lock Brake System)

– Purpose: Prevents wheel lockup [7]

### Engine Management Unit

– Role: Monitors sensors [7]

### Powertrain Elements

– Includes: Differential [7]

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## Service Procedure Stages

1. **Symptom Assessment**:

Perform visual inspection

2. **Part Evaluation**:

Test continuity

3. **Component Installation**:

Follow torque specs

4. **Final Quality Check**:

Confirm warning light reset

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## Critical Instruments

| **Tool Type** | **Examples** | **Purpose** |

|—|—|—|

| OBD-II Tool | Autel | Retrieve DTCs |

| Physical Equipment | Torque wrench | Component repair |

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## Technical Data Resources

### Auto Repair Source

– Features:

Component locations [8]

OEM specifications

### Smartphone Tools

– Auto Repair Documents:

Component testing guides [5]

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## Budget Repair Strategies

– Preventative service extends vehicle life

– Master code scanning to avoid unnecessary repairs

– Select certified components when OEM prices prohibitive [7]