### P0420 Emissions Control Malfunction
– Common Causes:
Faulty oxygen sensor [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 System Too Lean
– Possible Defects:
Fuel delivery problems
– Diagnostic Steps:
Check fuel pressure [1][7]
—
## Auto Repair Terminology
### Skid Prevention Technology
– Purpose: Enables safe braking [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Monitors sensors [7]
### Powertrain Elements
– Contains: Drive axles [7]
—
## Mechanical Fixing Workflow
1. **Initial Diagnosis**:
Scan DTCs
2. **System Verification**:
Measure resistance
3. **Parts Replacement**:
Clear error codes
4. **Final Quality Check**:
Confirm warning light reset
—
## Necessary Equipment
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | Autel | Live data streaming |
| Physical Equipment | Smoke machine | Electrical testing |
—
## Technical Data Resources
### Vehicle Service Database
– Capabilities:
TSB access [8]
OEM specifications
### Smartphone Tools
– Vehicle Service App:
Component testing guides [5]
—
## Budget Repair Strategies
– Regular maintenance extends vehicle life
– Master code scanning to prevent mechanic overselling
– Select certified components when budget constrained [7]