Fault code P0382 is called “Glow Plug/Heater Circuit “B” Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0382
OBD-II Trouble Code P0382 is a general code that is defined as “Glow plug “B” heater circuit failure”. It is set when the Powertrain Control Module (PCM) detects a general fault or failure. Which has occurred in the glow plug control circuit on the diesel engine.
Glow plugs are used on diesel engines to provide an intense heat source. Which is necessary to provide better combustion of the fuel-air mixture when the engine is cold or the temperature is below the minimum threshold.
At low ambient temperatures, it is very difficult to ignite the diesel mixture because it may not be compressed enough to initiate combustion. Diesel engines use electrically heated glow plugs to eliminate these problems. To create a heat source in the precombustion chamber of each cylinder, to ignite the fuel-air mixture at the peak of compression.
Regardless of the ambient temperature, the glow plug control circuit will not be activated. If the engine coolant temperature exceeds a predetermined minimum threshold.
This is necessary both to extend the service life of the glow plugs and to prevent premature detonation of the fuel-air mixture.
Glow plugs are critical components of a diesel engine. Because if they fail, there is a high probability that a cold engine will not start or will start with great difficulty.
Consequently, if the glow plug control circuit fails, the PCM or other control module will set code P0382. A special light on the control panel may also come on.
Note that vehicle manufacturers do not always number circuits or parts of circuits the same way. Therefore, it is necessary to look in the technical manual to see which part of the glow plug control circuit is marked with a “B”.
Symptoms of vehicle malfunctions
The main signal that an error P0382 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
- The glow plug start standby light is on longer than usual (may be permanently on).
- The engine may crank but not start (especially in cold weather).
- Possible white smoke from the exhaust pipe due to insufficient heating of fuel before combustion.
Depending on the symptoms, the error P0382 may be minor or serious. However, the problem should not be ignored, as the appearance of this error may cause problems with the engine.
Factors that can cause this error code
The error code P0382 can mean that one or more of the following problems have occurred:
- One or more glow plugs are defective.
- Faulty glow plug wiring.
- Blown fuse or fusible link.
- Faulty glow plug relay.
- Faulty ignition switch is faulty.
- Glow plug control module.
- Glow plug timer defective.
- The engine coolant temperature sensor may have failed.
- Sometimes the cause is a defective PCM module.
How to fix or reset OBD-2 code P0382
Some suggested steps for troubleshooting and fix the error code P0382:
- Read all stored data and error codes with a standard OBD-II scan tool.
- Clear the error codes from the computer memory and recheck the system to see if error P0382 appears again.
- If the error code disappears, then the problem is intermittent and there is nothing wrong with the glow plug circuit.
- If the code appears again, visually inspect the electrical wires and connectors as well as the fuses.
- Then check the glow plugs as well as the control relay.
- Replace defective components if necessary.
Diagnose and repair of problems
It is best to start diagnostics with the Technical Service Bulletins (TSB), your problem P0382 is probably known and described in them. Then you should check the appropriate fuses, replace them if they are blown. Next, you should test the glow plug relays.
Visually inspect the glow plugs, wiring, and connectors for corrosion, bent, and loose wire contacts. Look for loose screws or nuts on the wiring connections. If necessary all defects should be repaired.
Check the connectors of the wiring harness for resistance using a digital voltmeter and compare with the manufacturer’s specifications. Do the same with the wires going to the glow plugs.
To check the glow plug itself, you must remove it, apply 12 V voltage to it, and ground the body for 2-3 seconds. If the glow plug is red hot, it is working, if it is dull red or not red at all, it must be replaced.
On which vehicles does this problem occur most frequently
Fault code P0382 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Citroen (Jumper)
- Dodge
- Fiat (Ducato)
- Great Wall
- Hover
- Hyundai (Ducato)
- Peugeot (206, Boxer)
Fault code P0382 can sometimes be found with other errors. The most common are the following: P0380, P0381, P0383, P0384, P0670, P0671, P0672, P0673, P0674, P0675, P0676, P0677, P0678, P0679, P0680, P0681, P0682, P0683, P0684.
