### P0420 Emissions Control Malfunction
– Frequent Reasons:
Faulty oxygen sensor [1]
– Common Solutions:
Diagnose fuel trim https://carautorepair.site/
### P0171 Air-Fuel Ratio Error
– Potential Issues:
Vacuum leaks
– Diagnostic Steps:
Check fuel pressure [1][7]
—
## Vehicle Service Vocabulary
### Skid Prevention Technology
– Function: Prevents wheel lockup [7]
### Engine Management Unit
– Role: Monitors sensors [7]
### Transmission System Parts
– Contains: Transmission [7]
—
## Mechanical Fixing Workflow
1. **Problem Identification**:
Scan DTCs
2. **Part Evaluation**:
Test continuity
3. **Parts Replacement**:
Clear error codes
4. **Post-Repair Verification**:
Ensure proper operation
—
## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | Innova | Live data streaming |
| Physical Equipment | Multimeter | Electrical testing |
—
## Service Information References
### Mechanical Information System
– Capabilities:
Wiring diagrams [8]
Technical illustrations
### Digital Assistants
– Vehicle Service App:
Component testing guides [5]
—
## Budget Repair Strategies
– Preventative service avoids costly repairs
– Master code scanning to prevent mechanic overselling
– Select certified components when OEM prices prohibitive [7]