### P0420 Catalyst System Efficiency Below Threshold
– Typical Sources:
Faulty oxygen sensor [1]
– Suggested Repairs:
Diagnose fuel trim https://carautorepair.site/
### P0171 System Too Lean
– Likely Problems:
Fuel delivery problems
– Testing Procedure:
Check fuel pressure [1][7]
—
## Car Maintenance Terms
### Skid Prevention Technology
– Function: Maintains steering control [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Manages fuel injection [7]
### Transmission System Parts
– Contains: Drive axles [7]
—
## Repair Process Steps
1. **Initial Diagnosis**:
Scan DTCs
2. **Component Testing**:
Check voltage
3. **Parts Replacement**:
Clear error codes
4. **Final Quality Check**:
Confirm warning light reset
—
## Necessary Equipment
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| OBD-II Tool | Innova | Retrieve DTCs |
| Physical Equipment | Multimeter | Electrical testing |
—
## Technical Data Resources
### Vehicle Service Database
– Capabilities:
TSB access [8]
Factory repair procedures
### Smartphone Tools
– Auto Repair Documents:
ECU pinouts [5]
—
## Cost-Saving Tips
– Regular maintenance extends vehicle life
– Learn basic diagnostics to avoid unnecessary repairs
– Use aftermarket parts when budget constrained [7]
