### P0420 Catalyst System Efficiency Below Threshold

– Frequent Reasons:

Faulty oxygen sensor [1]

– Suggested Repairs:

Repair exhaust system https://carautorepair.site/

### P0171 System Too Lean

– Potential Issues:

Fuel delivery problems

– Diagnostic Steps:

Smoke test intake [1][7]

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## Auto Repair Terminology

### ABS (Anti-Lock Brake System)

– Purpose: Enables safe braking [7]

### Vehicle Computer System

– Responsibility: Controls ignition timing [7]

### Powertrain Elements

– Includes: Differential [7]

—

## Repair Process Steps

1. **Problem Identification**:

Scan DTCs

2. **System Verification**:

Test continuity

3. **Parts Replacement**:

Follow torque specs

4. **Final Quality Check**:

Test drive vehicle

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## Necessary Equipment

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

|—|—|—|

| Code Reader | Autel | Live data streaming |

| Mechanical Tools | Smoke machine | Component repair |

—

## Repair Documentation Sources

### Vehicle Service Database

– Capabilities:

Component locations [8]

Factory repair procedures

### Smartphone Tools

– Auto Repair Documents:

Component testing guides [5]

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## Affordable Maintenance Advice

– Regular maintenance avoids costly repairs

– Understand DTC meanings to prevent mechanic overselling

– Install quality alternatives when budget constrained [7]