## Frequent Vehicle Error Codes

### P0420 Catalyst System Efficiency Below Threshold

– Typical Sources:

Faulty oxygen sensor [1]

– Suggested Repairs:

Diagnose fuel trim https://carautorepair.site/

### P0171 Air-Fuel Ratio Error

– Possible Defects:

Fuel delivery problems

– Diagnostic Steps:

Smoke test intake [1][7]

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## Vehicle Service Vocabulary

### ABS (Anti-Lock Brake System)

– Function: Enables safe braking [7]

### Vehicle Computer System

– Responsibility: Controls ignition timing [7]

### Powertrain Elements

– Includes: Transmission [7]

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## Service Procedure Stages

1. **Initial Diagnosis**:

Perform visual inspection

2. **Component Testing**:

Check voltage

3. **Parts Replacement**:

Clear error codes

4. **Final Quality Check**:

Confirm warning light reset

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## Essential Tools

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

|—|—|—|

| OBD-II Tool | Autel | Live data streaming |

| Hand Instruments | Multimeter | Component repair |

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## Repair Documentation Sources

### Vehicle Service Database

– Capabilities:

Component locations [8]

Factory repair procedures

### Smartphone Tools

– Vehicle Service App:

Component testing guides [5]

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## Affordable Maintenance Advice

– Preventative service extends vehicle life

– Master code scanning to prevent mechanic overselling

– Use aftermarket parts when OEM prices prohibitive [7]