### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Exhaust leaks [1]
– Suggested Repairs:
Repair exhaust system https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Likely Problems:
Faulty MAF sensor
– Testing Procedure:
Smoke test intake [1][7]
—
## Vehicle Service Vocabulary
### Electronic Braking System
– Function: Maintains steering control [7]
### Vehicle Computer System
– Role: Manages fuel injection [7]
### Drivetrain Components
– Contains: Drive axles [7]
—
## Service Procedure Stages
1. **Initial Diagnosis**:
Perform visual inspection
2. **Component Testing**:
Test continuity
3. **Defective Unit Swap**:
Clear error codes
4. **Post-Repair Verification**:
Test drive vehicle
—
## Essential Tools
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | Autel | Retrieve DTCs |
| Hand Instruments | Multimeter | Component repair |
—
## Service Information References
### Auto Repair Source
– Features:
Wiring diagrams [8]
Technical illustrations
### Digital Assistants
– Auto Repair Documents:
Electrical diagrams [5]
—
## Budget Repair Strategies
– Preventative service prevents major failures
– Learn basic diagnostics to prevent mechanic overselling
– Select certified components when OEM prices prohibitive [7]
