Possible causes of P1684 include:
* Faulty PCM: While less common than other causes, the PCM itself could be failing.
* Blown fuse: Check the fuses related to the PCM and ignition system. Your owner's manual will show the fuse box layout.
* Damaged wiring: Look for broken, frayed, or corroded wires in the PCM's power supply circuit. This often occurs near the PCM connector.
* Bad PCM relay: Some Intrepids have a relay specifically for the PCM. This relay could be faulty.
* Ignition switch problems: A failing ignition switch can interrupt power to the PCM.
* Battery or alternator issues: A weak battery or failing alternator can lead to insufficient voltage for the PCM.
Troubleshooting Steps:
1. Check the fuses: This is the easiest and most common first step. Replace any blown fuses.
2. Inspect the wiring: Carefully examine the wiring harness leading to and from the PCM. Look for any signs of damage.
3. Check the battery and alternator: Ensure the battery has a good charge and the alternator is functioning correctly. Have this tested at an auto parts store.
4. Test the PCM relay (if applicable): If your Intrepid uses a PCM relay, check its functionality. This might require a multimeter.
5. Professional Diagnosis: If you're not comfortable with electrical diagnostics, take your Intrepid to a qualified mechanic. They have the tools and expertise to pinpoint the exact cause and perform the necessary repairs. This code usually requires a scan tool beyond a basic code reader to fully understand the situation.
Ignoring this code can lead to serious drivability problems, including a complete engine shutdown. Don't drive the car extensively until the problem is diagnosed and fixed.
