### P0420 Catalyst System Efficiency Below Threshold
– Common Causes:
Faulty oxygen sensor [1]
– Recommended Fixes:
Repair exhaust system https://carautorepair.site/
### P0171 System Too Lean
– Likely Problems:
Fuel delivery problems
– Diagnostic Steps:
Inspect injectors [1][7]
—
## Car Maintenance Terms
### Skid Prevention Technology
– Function: Prevents wheel lockup [7]
### ECM/ECU (Engine Control Module)
– Responsibility: Controls ignition timing [7]
### Powertrain Elements
– Includes: Drive axles [7]
—
## Mechanical Fixing Workflow
1. **Symptom Assessment**:
Conduct road test
2. **System Verification**:
Check voltage
3. **Defective Unit Swap**:
Follow torque specs
4. **Post-Repair Verification**:
Test drive vehicle
—
## Critical Instruments
| **Tool Type** | **Examples** | **Purpose** |
|—|—|—|
| Code Reader | BlueDriver | Live data streaming |
| Hand Instruments | Torque wrench | Component repair |
—
## Technical Data Resources
### Auto Repair Source
– Capabilities:
Component locations [8]
Technical illustrations
### Digital Assistants
– Vehicle Service App:
Component testing guides [5]
—
## Cost-Saving Tips
– Routine checkups prevents major failures
– Master code scanning to prevent mechanic overselling
– Use aftermarket parts when OEM prices prohibitive [7]
