### P0420 Emissions Control Malfunction
– Frequent Reasons:
Faulty oxygen sensor [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 Fuel Mixture Imbalance
– Potential Issues:
Fuel delivery problems
– Diagnostic Steps:
Smoke test intake [1][7]
—
## Auto Repair Terminology
### ABS (Anti-Lock Brake System)
– Function: Maintains steering control [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Controls ignition timing [7]
### Transmission System Parts
– Contains: Differential [7]
—
## Mechanical Fixing Workflow
1. **Problem Identification**:
Scan DTCs
2. **Component Testing**:
Check voltage
3. **Parts Replacement**:
Clear error codes
4. **Final Quality Check**:
Test drive vehicle
—
## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Autel | Live data streaming |
| Mechanical Tools | Torque wrench | Component repair |
—
## Repair Documentation Sources
### Mechanical Information System
– Features:
Component locations [8]
Factory repair procedures
### Smartphone Tools
– Vehicle Service App:
Component testing guides [5]
—
## Cost-Saving Tips
– Preventative service prevents major failures
– Master code scanning to prevent mechanic overselling
– Use aftermarket parts when budget constrained [7]