What Does P1684 Mean?
P1684 is a manufacturer-specific diagnostic trouble code used exclusively by Chrysler vehicles (including Dodge, Jeep, and RAM brands). This code is set when the vehicle’s onboard diagnostic system detects that either the diagnostic trouble codes have been cleared (erased) or the battery has been disconnected and reconnected.
Unlike most OBD-II codes that indicate a malfunction, P1684 is purely informational. It’s the computer’s way of noting that a reset event has occurred. This code is particularly useful for technicians and vehicle owners because it provides a timestamp of when the system was last cleared, which can help diagnose intermittent issues or verify that service work was completed.
Common Symptoms
- Check Engine Light (CEL) illuminated on the dashboard
- No drivability issues or performance problems
- Vehicle operates normally despite the warning light
- Code appears in diagnostic scanner after battery disconnect or code clearing
- May appear alongside other diagnostic codes if other faults exist
Possible Causes
- Battery Disconnection (Most Common) – The battery was disconnected for service, replacement, or troubleshooting purposes. This is the primary trigger for P1684 on Chrysler vehicles.
- Diagnostic Codes Cleared – A technician or vehicle owner used a diagnostic scanner to clear existing trouble codes from the system.
- Battery Replacement – Installation of a new battery naturally triggers this code as the system re-initializes.
- Loose Battery Terminal – A corroded or loose battery cable connection that was recently cleaned or tightened can trigger this code.
- Battery Voltage Drop – Severe voltage fluctuations or a dying battery that was replaced can set this code.
- Electrical Service Work – Any work involving the electrical system that required battery disconnection.
Diagnostic Steps
- Scan for Additional Codes – Use a diagnostic scanner to check if other trouble codes are present. P1684 alone is informational, but other codes may indicate actual problems.
- Review Service History – Check recent service records or ask the vehicle owner if battery work, electrical service, or code clearing was performed recently.
- Inspect Battery and Terminals – Visually inspect the battery, battery cables, and terminals for corrosion, looseness, or damage. Clean corroded terminals with a wire brush if necessary.
- Test Battery Voltage – Use a multimeter to verify the battery is holding proper voltage (typically 12.6V when the engine is off, 13.5-14.5V when running).
- Check for Parasitic Drain – If the battery is weak, perform a parasitic draw test to ensure no components are draining power when the vehicle is off.
- Clear the Code – Once you’ve confirmed no other issues exist, clear P1684 using a diagnostic scanner. The code should not return unless the battery is disconnected again.
- Test Drive – Drive the vehicle for 10-15 minutes to allow the system to complete its initialization cycle and verify no other codes appear.
Repair Cost Estimates
- No Repair Needed (Most Cases) – $0. If P1684 is the only code and the vehicle operates normally, no repair is required.
- Battery Terminal Cleaning – $0-$50 (DIY) or $50-$100 (shop labor) if corrosion is found and cleaned.
- Battery Replacement – $100-$300 depending on battery type and vehicle model (if the battery is failing).
- Diagnostic Scan – $50-$150 if a professional scan is needed to verify no other codes are present.
Can I Still Drive?
Yes, it is safe to drive. P1684 is a low-severity, informational code that does not indicate a malfunction or safety issue. Your vehicle will operate normally, and the Check Engine Light is simply notifying you that a reset event was detected.
Important caveat: If P1684 appears alongside other trouble codes, those additional codes may indicate actual problems that require diagnosis and repair. Always scan for all codes present before assuming the vehicle is safe to drive.
You can safely drive to a repair facility to have the code cleared and verified, but it’s recommended to address this promptly to ensure the diagnostic system is functioning properly and to rule out any underlying issues.
Frequently Asked Questions
What’s the difference between P1684 and other check engine codes?
P1684 is unique because it’s not a fault code—it’s a system notification. While most OBD-II codes indicate a malfunction (like a faulty sensor or emission system problem), P1684 simply records that the diagnostic system was reset. It’s more of a “heads up” than an error.
Will P1684 go away on its own?
No, P1684 will not clear automatically. Once set, it remains in the vehicle’s memory until it’s manually cleared using a diagnostic scanner. However, if you don’t clear it, it will eventually age out after several drive cycles (typically 40-80 cycles depending on the vehicle), but it’s better to clear it promptly.
Can I clear P1684 myself?
Yes, if you have access to an OBD-II diagnostic scanner. Many auto parts stores offer free code reading and clearing services. However, if you’re unsure whether other codes are present, it’s recommended to have a professional scan performed first to ensure no actual faults are being masked.
Why does P1684 keep coming back after I clear it?
If P1684 reappears immediately after clearing, it indicates the battery is being disconnected repeatedly or there’s a chronic electrical issue. Check for loose battery terminals, a failing battery, or electrical work that’s still in progress. If the code returns after several drive cycles without any battery work, there may be an underlying electrical problem requiring professional diagnosis.