### P0420 Catalyst System Efficiency Below Threshold
– Common Causes:
Faulty oxygen sensor [1]
– Common Solutions:
Repair exhaust system https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Possible Defects:
Faulty MAF sensor
– Diagnostic Steps:
Check fuel pressure [1][7]
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## Vehicle Service Vocabulary
### ABS (Anti-Lock Brake System)
– Purpose: Enables safe braking [7]
### Vehicle Computer System
– Responsibility: Monitors sensors [7]
### Powertrain Elements
– Includes: Drive axles [7]
—
## Mechanical Fixing Workflow
1. **Problem Identification**:
Conduct road test
2. **Part Evaluation**:
Test continuity
3. **Parts Replacement**:
Use OEM parts
4. **Post-Repair Verification**:
Ensure proper operation
—
## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Diagnostic Scanner | Innova | Live data streaming |
| Hand Instruments | Smoke machine | Electrical testing |
—
## Repair Documentation Sources
### Auto Repair Source
– Features:
TSB access [8]
Technical illustrations
### Digital Assistants
– Auto Repair Documents:
ECU pinouts [5]
—
## Budget Repair Strategies
– Regular maintenance extends vehicle life
– Learn basic diagnostics to prevent mechanic overselling
– Use aftermarket parts when budget constrained [7]
