P0621
Critical Severity (Level 5)Generator Lamp/L Terminal Circuit
OBD-II diagnostic trouble code P0621indicates a fault detected by the vehicle's onboard computer. This code applies to all OBD-II compliant vehicles and should be addressed promptly to avoid potential engine or emissions system damage.
Severity Level 5 — Critical
This code indicates a critical issue that may cause severe engine damage or complete engine failure. Stop driving immediately and have the vehicle towed to a repair shop. Continuing to drive could result in catastrophic engine damage and costly repairs.
Common Symptoms
- Check engine light on
- Reduced fuel economy
- Possible rough idle or hesitation
Possible Causes
- Generator Lamp/L Terminal Circuit
- Manufacturer-specific condition
- Fault in related component or circuit
Common Fixes
- Diagnose with professional OBD2 scan tool
- Check manufacturer TSBs
- Inspect related components per service manual
Estimated Repair Cost
$500 – $2000(typical range; varies by vehicle make and model)
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Explore Repair Costs
Worried about repair costs?
Get transparent estimates and verify your mechanic's quote before authorizing repairs.
Related Discussions
See what other car owners are saying about this code and related repairs.
View P0621 discussions in the community