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P0384 is a diagnostic trouble code (DTC) for "Glow Plug Control Module Control Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $79.99. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0384 code is stored when the PCM detects a malfunction in the voltage reading of the glow plug heater circuit – specifically, a reading that is too high. This will often be accompanied by other glow plug circuit codes.
The glow plug system provides the heat that the engine needs to begin combustion in cold temperatures. Glow plugs heat before, during, and after cranking, and the temperature and voltage of the glow plugs is monitored by the ECM. If the voltage reading detected by the ECM is more than 10% higher than the reading recommended by the manufacturer, the PCM will store the P0384 code.
Most of the time, a faulty glow plug is to blame for the P0384 code. However, there could be quite a few other causes, including:
Most vehicle owners will observe a slow start, and possibly even white smoke from the exhaust when the vehicle does start. The engine may be exceedingly loud, and the glow plug indicator lamp may stay on constantly. The code will be stored in the PCM, and the Check Engine lamp will illuminate.
After an OBD-II scanner detects the P0384 code, a technician should begin with a visual inspection of all the wiring and connectors related to the glow plug heater circuit. Any damaged elements should be replaced, reconnected, or repaired as necessary. They should then clear the code and perform a test drive, checking that the Check Engine light does not reappear.
If the light does reappear, the mechanic can then move on to checking each of the individual glow plug connectors for the proper voltage and ground signals. As the mechanic moves through each potential repair to find the issue, they should be sure to clear the code from the PCM and retest the system after each step. This will ensure that they do not waste time or money repairing things when the issue has already been fixed.
Most often, the wiring, connectors, and/or the glow plug itself are to blame. However, many technicians report that the glow plug timers and glow plug relays are often replaced when they don’t need to be. Mechanics should be sure to check wiring and commonly at-fault parts before replacing anything.
If the P0384 code is stored in the PCM, the vehicle should be repaired right away – especially if the weather is cold. This issue can cause major issues with the start up and operation of a vehicle.
There are many ways that a technician can address a P0384 code detection. They include:
While attempting to diagnose and repair the issue behind the P0384 code, it is important to be careful and wear the proper safety gear. Glow plugs get very hot very quickly; within a few seconds, a properly-functioning glow plug will be orange from the heat.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.