Having problems with your 2004 Mercury Grand Marquis ?
Resetting check engine light on 2004 grand marquis
Requires a code reader.
Repair Help & Product Troubleshooting for 2004 Mercury Grand Marquis
Tips for a great answer:- Provide details, support with references or personal experience .
- If you need clarification, ask it in the comment box .
- It's 100% free, no registration required.