### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Faulty oxygen sensor [1]
– Suggested Repairs:
Replace catalytic converter https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Vacuum leaks
– Testing Procedure:
Check fuel pressure [1][7]
—
## Vehicle Service Vocabulary
### ABS (Anti-Lock Brake System)
– Function: Prevents wheel lockup [7]
### Engine Management Unit
– Responsibility: Controls ignition timing [7]
### Transmission System Parts
– Contains: Drive axles [7]
—
## Service Procedure Stages
1. **Problem Identification**:
Conduct road test
2. **Component Testing**:
Measure resistance
3. **Parts Replacement**:
Follow torque specs
4. **Final Quality Check**:
Ensure proper operation
—
## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | BlueDriver | Retrieve DTCs |
| Hand Instruments | Smoke machine | Component repair |
—
## Repair Documentation Sources
### Auto Repair Source
– Capabilities:
Component locations [8]
Technical illustrations
### Mobile Applications
– Vehicle Service App:
ECU pinouts [5]
—
## Cost-Saving Tips
– Routine checkups prevents major failures
– Understand DTC meanings to prevent mechanic overselling
– Install quality alternatives when OEM prices prohibitive [7]
