Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2004 Mercury MontereyFACTORY OEM SERVICE PROCEDURE
Navigation System Module C4209
WARNING: This page is about a different car, the 2004 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
NAVIGATION SYSTEM MODULE C4209 PINS DESCRIPTION
| Pin Number(s) | Circuit Designation/Description | Normal Condition/Measurement |
|---|---|---|
| 4 | 4-EG17 (GY/BK) SCP communication circuit | Less than 5 ohms between the navigation system module and the DLC. Greater than 10,000 ohms to ground with all network modules disconnected. |
| 16 | 5-EG17 (BU/YE) SCP communication circuit | Less than 5 ohms between the navigation system module and the DLC. Greater than 10,000 ohms to ground with all network modules disconnected. |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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