### P0420 Catalyst System Efficiency Below Threshold
– Common Causes:
Exhaust leaks [1]
– Recommended Fixes:
Diagnose fuel trim https://carautorepair.site/
### P0171 System Too Lean
– Potential Issues:
Faulty MAF sensor
– Testing Procedure:
Check fuel pressure [1][7]
—
## Auto Repair Terminology
### ABS (Anti-Lock Brake System)
– Function: Prevents wheel lockup [7]
### Vehicle Computer System
– Role: Controls ignition timing [7]
### Drivetrain Components
– Includes: Transmission [7]
—
## Mechanical Fixing Workflow
1. **Symptom Assessment**:
Scan DTCs
2. **Component Testing**:
Measure resistance
3. **Parts Replacement**:
Follow torque specs
4. **System Validation**:
Ensure proper operation
—
## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | Innova | Retrieve DTCs |
| Physical Equipment | Smoke machine | Component repair |
—
## Technical Data Resources
### Mechanical Information System
– Features:
Component locations [8]
Technical illustrations
### Digital Assistants
– Vehicle Service App:
Electrical diagrams [5]
—
## Cost-Saving Tips
– Routine checkups avoids costly repairs
– Understand DTC meanings to avoid unnecessary repairs
– Install quality alternatives when budget constrained [7]