What does it mean?
This code is a generic powertrain group code. It is considered generic because it applies to all makes and models of vehicles (1996 and newer), although specific repair steps may vary slightly by model.
The description for GM vehicles is slightly different: glow plug performance conditions.
The glow plug operates when starting a cold diesel engine (the Powertrain Control Module PCM uses the coolant temperature when the ignition is turned on to determine this). The glow plug heats up for a short period to increase the cylinder temperature, which allows diesel fuel to ignite more easily. If there is an open in the glow plug or circuit, this DTC will be set.
On some diesel engines, the PCM will activate the glow plugs for a period after the engine is running to reduce white smoke and engine noise.
A typical diesel engine glow plug:
Basically, code P0382 means that the PCM has detected a fault in the glow plug/heater circuit “B”.
Note: This DTC is very similar to P0380, which refers to circuit “A”. If you have multiple DTC codes, correct them in the order they appear.
Symptoms
Symptoms of a P0382 trouble code may include:
Malfunction Indicator Lamp (MIL) illumination
Glow plug/Wait To Start indicator stays on longer than normal (may be continuously lit)
Hard starting condition, especially in cold weather
Potential Causes
Causes
Potential causes of this DTC may include:
Fault in glow plug wiring (open, short to ground, etc.)
Faulty glow plug
Blown fuse
Faulty glow plug relay
Faulty glow plug module
Diagnostic Steps
and Possible Solutions
If you have a GM truck or really any vehicle for that matter, check for known issues such as TSBs (Technical Service Bulletins) related to this code.
Check associated fuses, replace them if blown. Test the glow plug relay if possible.
Visually inspect glow plugs, wiring, and connectors for corrosion, bent/loose wiring pins, loose screws/nuts on wiring connections, burnt appearance. Repair as necessary.
Check the resistance of the harness connectors using a digital volt ohmmeter (DVOM). Compare to manufacturer specifications.
Disconnect the glow plug wires, measure resistance using the DVOM, compare to specifications.
Use a DVOM to check that the glow plug wiring connector is powered and grounded.
If replacing a glow plug, be sure to start it in the threads by hand, just as you would with a spark plug.
If you really want to test the glow plug, you can always remove them, apply 12V to the terminal and ground the body for 2-3 seconds. If it glows red, it’s good; if it’s dull red or not red, it’s no good.
If you have access to an advanced scan tool, there may be functions you can use on it related to the glow plug wiring circuit.
Other DTCs related to glow plugs: P0380, P0381, P0383, P0384, P0670, P0671, P0672, P0673, P0674, P0675, P0676, P0677, P0678, P0679, P0680, P0681, P0682, P068.