Need a P0684 diagnosis? Trust our experts.
Oops! We got lost!
Your location cannot be detected. Please enter your zipcode for nearby shops.
P0684 Severity
Identifying an OBD code is just the start of a complete diagnostic routine. Most trouble codes are caused by a sensor reporting a value that is out of range. Just replacing a sensor may not fix underlying issues. Be sure to understand the code, the part or system in your car that the code refers to, and the risks of delaying professional repair.
Proper diagnosis will save you time and money on unnecessary repairs.
Urgent codes indicate immediate action is necessary. These are urgent and significant malfunctions that can cause severe damage to the vehicle or harm the driver and passengers.
The Glow Plug Module controls the glow plugs used on diesel engines to preheat the cylinder before the engine is started. If the engine control module (PCM) cannot communicate with the Glow Plug Module, the PCM will set code P0684.
RepairPal Car Genius™ is a free resource for vehicle owners seeking advice on maintenance, auto repair, shop inquiries, estimates, and finding a trustworthy repair shop in your area.
Call us at 877-913-1554
Available 9am – 6pm ET Monday through Friday
OBD-II Code Hard or no start in cold weather is defined as a Glow Plug Control Module to PCM Communication Circuit
The Glow Plug Module controls the glow plugs used on diesel engines to preheat the cylinder before the engine is started. If the engine control module (PCM) cannot communicate with the Glow Plug Module, the PCM will set code P0684.