### P0420 Catalyst System Efficiency Below Threshold
– Common Causes:
Faulty oxygen sensor [1]
– Recommended Fixes:
Replace catalytic converter https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Potential Issues:
Faulty MAF sensor
– Diagnostic Steps:
Check fuel pressure [1][7]
—
## Vehicle Service Vocabulary
### Skid Prevention Technology
– Purpose: Maintains steering control [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Manages fuel injection [7]
### Transmission System Parts
– Contains: Drive axles [7]
—
## Service Procedure Stages
1. **Initial Diagnosis**:
Conduct road test
2. **System Verification**:
Check voltage
3. **Parts Replacement**:
Follow torque specs
4. **System Validation**:
Test drive vehicle
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## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | Innova | Live data streaming |
| Mechanical Tools | Smoke machine | Electrical testing |
—
## Repair Documentation Sources
### Mechanical Information System
– Capabilities:
TSB access [8]
OEM specifications
### Mobile Applications
– Auto Repair Documents:
Component testing guides [5]
—
## Cost-Saving Tips
– Routine checkups extends vehicle life
– Understand DTC meanings to prevent mechanic overselling
– Select certified components when budget constrained [7]
