P0384 OBD-II Trouble Code: Glow Plug Control Module Control Circuit High

Our certified mechanics come to you · Get a fair and transparent estimate upfront


Cost of diagnosing the P0384 code

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 $154.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $50.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate* Credit towards follow-up repair Earliest Availability
Ford $154.99 $50.0
Toyota $154.99 $50.0
BMW $164.99 $50.0

*Estimates may vary by market

SCHEDULE P0384 DIAGNOSTIC Get a fair and transparent estimate upfront

P0384 code definition

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.

What the P0384 code means

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.

What causes 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:

  • Faulty glow plug relay
  • Bad glow plug module or timer
  • Loose, corroded, or shorted glow plug circuit electrical connectors
  • Loose, shorted, or open wiring in the glow plug heater circuit
  • Blown fuses, which also indicate an underlying issue elsewhere
  • Open or shorted glow plug harness

What are the symptoms of the P0384 code?

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.

How does a mechanic diagnose the P0384 code?

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.

Common mistakes when diagnosing the P0384 code

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.

How serious is the P0384 code?

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.

What repairs can fix the P0384 code?

There are many ways that a technician can address a P0384 code detection. They include:

  • Replacing a faulty glow plug
  • Replacing a faulty glow plug relay
  • Replacing a bad glow plug module or timer
  • Repairing loose, corroded, or shorted glow plug circuit electrical connectors
  • Repairing loose, shorted, or open wiring in the glow plug heater circuit
  • Replacing blown fuses, and searching for and repairing the underlying issue that a blown fuse can indicate
  • Repairing an open or shorted glow plug harness

Additional comments for consideration regarding the P0384 code

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.

Need help with a P0384 code?

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.

Check Engine Light
trouble codes
P0383

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0384 code.

SCHEDULE P0384 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(8600)

Rating Summary
8017
273
65
46
199
8017
273
65
46
199
 at YourMechanic

Brandon

9 years of experience
133 reviews
Brandon
9 years of experience
Ford Escort L4-2.0L - Check Engine Light is on - Nashville, Tennessee
Brandon showed up ahead of schedule, was very personable and diagnosed my problems. He also scheduled my next appointments which will be with him.
 at YourMechanic

William

23 years of experience
33 reviews
William
23 years of experience
Lexus IS250 V6-2.5L - Check Engine Light is on - Mableton, Georgia
Arrived early which was great. William was courteous, and attentive to the issue. Even though it took several attempts I'm so happy he was determined to fix it and he did!
 at YourMechanic

Dan

40 years of experience
1080 reviews
Dan
40 years of experience
Plymouth Grand Voyager - Check Engine Light is on - Lawrenceville, Georgia
Mr. Dan Barber was quite patient, courteous and quite knowledgeable. From my observation, Mr. Barber appears to be quite professional.
 at YourMechanic

Christopher

9 years of experience
120 reviews
Christopher
9 years of experience
Ford Fiesta L4-1.6L - Check Engine Light is on - Smyrna, Georgia
Chris communicated with us each step of the way up until his arrival. He listened well, was knowledgeable, and was prepared. He took the time to diagnose the problem, explained the what, why and how and provided a solution. I would definitely recommend him and will use him again.


More related articles

P0465 OBD-II Trouble Code: Purge Flow Sensor Circuit Malfunction
P0465 means the purge flow sensor in the evaporative control system is malfunctioning, usually in conjunction with other failures within the system.
P2659 OBD-II Trouble Code: A Rocker Arm Actuator Ctrl Circuit High Bank2
P2659 means the Powertrain Control Module has detected a short in the rocker arm actuator control circuit which causes reduced engine performance.
P3441 OBD-II Trouble Code: Cylinder 6 Deactivation/Intake Valve Control Circuit/Open
P3441 means the PCM doesn’t receive the correct information from the MAF, MAP, and TP sensors due to clogged oil, low oil pressure, or shorts.

Related questions

Does the VIN number have to be in the ECM for the vehicle to run?
Some new ECMs will give you a certain amount of free starts before it will not start unless the VIN is added. I am not sure if this is the case with your ECM but you have a dealer telling...
I need help.
IIt looks like you have trouble codes from an import vehicle like an Audi or Mercedes Benz. I cannot decipher these codes without more information like the year make and model of the vehicle. Consider hiring an experienced technician like...
My oil pressure low light comes oil and I replaced the sensor several times but it still comes on
Hello, thank you for writing in. Particularly having the check engine light on, the vehicle will have set off diagnostic troubleshooting codes that pertain to whatever component has set off the warning lights. You will want to start by having...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (844) 997-3624 · hi@yourmechanic.com