From the Dodge factory service manual: P0401: EGR System Failure. Required change in air/fuel ratio not detected during diagnostic test. The PCM turns the EGR off and on momentarily. The oxygen sensor signal is monitored for changes in its output signal during this test, and if no significant change, or too much change is seen, the P0401 error flag is set. There can be a number of causes of this including: EGR solenoid or the valve itself stuck open/closed, EGR solenoid control circuitry failure, EGR solenoid vacuum supply issue (vacuum leak or pinch-off), fused ignition switch ouput open, or general intermittent error or issue with the PCM. The service manual lists a 12 step diagnostic procedure in three pages. P1684: The battery has been disconnected within the last 50 starts. Further note: P1684 is only a status and indicates that the PCM memory has been cleared within the last 50 ignition cycles, and does not indicate a problem.
The P1684 code simply means that the battery has been disconnected within the last 50 starts.
Trouble code P1684 means: The battery has been disconnected within the last 50 starts
It would be very rare for a P1684 code to turn the light on.
P0135-Right rear (or just) upstream O2 sensor heater failure P1684-The battery has been disconnected within the last 50 starts
Trouble code P1684 means: The battery has been disconnected within the last 50 starts P0601 is Internal Controller Failure- Common repair is Install new PCM and program it
What does code reading P1684 means for dodge neon car when you scan the engine
From what I've found, the P1684 Code means that the ECU has lost voltage within the last 50 starts. This could be from disconnecting the battery, a loose or corroded connection, or even a weak battery from repeated or long cranking.
Trouble Code P1684 means:The battery has been disconnected within the last 50 starts
Trouble code P1684 means:The battery has been disconnected within the last 50 starts
Trouble code P1684 means: The battery has been disconnected within the last 50 starts
Trouble code P1684 means: The battery has been disconnected within the last 50 starts
P1684 - Transmission - Battery Power To Module Disconnected if battery was disconected for a while or battery replaced, it can cause to set this DTC