P0380 DTC Glow Plug/Heater Circuit “A” Malfunction

Trouble Code P0380 OBD-II Datasheet

Glow plug / heater circuit "A"

What does this mean?

This code is a generic transmission code. It is considered universal as it applies to all makes and models of vehicles (1996 and newer), although the specific repair steps may differ slightly depending on the model.

The description of GM vehicles is slightly different: Glow plug operating conditions.

The glow plug fires when starting a cold diesel engine (the PCM uses the coolant temperature when the ignition is turned on to determine this). The glow plug is heated to red hot for a short period of time to raise the cylinder temperature, allowing the diesel fuel to ignite more easily. This DTC sets if the glow plug or circuit breaks.

On some diesel engines, the PCM will turn on the glow plugs for a period of time after starting the engine to reduce white smoke and engine noise.

Typical Diesel Engine Glow Plug:

Basically, a P0380 code means the PCM has detected a malfunction in the "A" glow plug / heater circuit.

Note. This DTC is very similar to P0382 on circuit B. If you have multiple DTCs, fix them in the order they appear.

Doing a quick search on the internet reveals that DTC P0380 appears to be more common on Volkswagen, GMC, Chevrolet and Ford diesel vehicles, however it is possible on any diesel powered vehicle (Saab, Citroen, etc.)

Symptoms of a P0380 trouble code may include:

When a P0380 trouble code is triggered, it will likely be accompanied by a Check Engine light as well as a Globe Plug warning light. The vehicle may also have trouble starting, may be excessively noisy during startup, and may produce white exhaust smoke.

Symptoms of a P0380 trouble code may include:

• Malfunction Indicator Lamp (MIL) Illumination
• Glow plug / Start-up standby light stays on longer than usual (may remain on)
• The condition is difficult to start, especially in cold weather

Possible reasons

Possible causes of this DTC may include:

• Malfunction in the glow plug wiring (open circuit, short to ground, etc.)
• Glow plug defective
• Open fuse
• Defective glow plug relay
• Glow plug module defective
• Faulty wiring and electrical connections, e.g. B. Corroded connectors or exposed cables

Diagnostic steps and possible solutions

• If you have a GM truck or any other vehicle, check for known issues such as TSB (technical service bulletins) that refer to this code.
• Check appropriate fuses, replace if blown. If possible, check the glow plug relay.
• Visually inspect glow plugs, wiring and connectors for corrosion, bent / loose wire pins, loose screws / nuts on wiring connections, and a burnt appearance. Repair if necessary.
• Test the harness connectors for resistance using a digital volt ohm meter (DVOM). Compare with manufacturer specifications.
• Disconnect glow plug wires, measure resistance with DVOM, compare with specification.
• Use the DVOM to verify that the glow plug wiring connector is receiving power and ground.
• When replacing a glow plug, be sure to manually insert it into the threads first, as if you were replacing a spark plug.
• If you really want to check the glow plugs, you can always remove them, apply 12V to the terminal, and ground the case for 2-3 seconds. If it's red hot, that's good; if it's dull red or not red, that's not good.
• If you have access to the advanced scan tool, you can use the functions related to the electrical circuit of the glow plug on it.

Other Glow Plug DTCs: P0381, P0382, P0383, P0384, P0670, P0671, P0672, P0673, P0674, P0675, P0676, P0677, P0678, P0679, P0680, P0681, P0682. P0683. P0684.

COMMON ERRORS WHEN DIAGNOSING CODE P0380

The most common error when diagnosing code P0380 is due to not following the OBD-II DTC diagnostic protocol correctly. Mechanics must always follow the correct protocol in order, which includes clearing numerous trouble codes in the order they appear.

Failure to follow proper protocol can also result in the replacement of the glow plug or relay if the real problem is the wires, connectors or fuses.

HOW SERIOUS CODE P0380 IS?

A detected P0380 code is unlikely to make the car run, but it will prevent the engine from working properly.

WHAT REPAIRS CAN FIX CODE P0380?

The most common repair for a P0380 DTC includes:

• Replacing the Glow Plug or Glow Plug Relay
• Replacement of heating wires, plugs and fuses
• Replacing the timer or glow plug module

ADDITIONAL COMMENTS REGARDING CODE P0380 CONSIDERATION

Although blown fuses in the glow plug heater circuit are usually associated with a P0380 code, they are usually the result of a larger problem. If a blown fuse is found, it should be replaced, but should not be assumed to be the only problem or cause of DTC P0380.

How to Fix P0380 Engine Code in 3 Minutes [2 DIY Methods / Only $9.29]

Need more help with your p0380 code?

If you still need help with DTC P0380, post a question in the comments below this article.

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