P0382
Glow Plug/Heater Circuit B
Encountering the engine check light code P0382 signifies an explicit mechanical or electrical operational breakdown categorized as "Glow Plug/Heater Circuit B". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
Storing code P0382 is your car's way of telling you something is wrong with the glow plug/heater circuit b. You may notice extended crank time when cold, rough idle on cold start, all of which are direct consequences of this malfunction. Short trips are generally acceptable, but avoid high-load driving and get this inspected soon.
Symptoms
Extended crank time when cold, rough idle on cold start
Common Causes
- Failed glow plugs on Bank 2
- Faulty secondary glow plug relay
- Damaged wiring circuit B
- Poor ground connection
How to Fix
- 1 Replace glow plugs on affected bank
- 2 Test and replace glow plug relay
- 3 Repair damaged wiring
- 4 Clean ground terminals
Technical Explanation
To set P0382, the PCM samples the affected circuit multiple times per second, comparing live readings against manufacturer-programmed operating windows. Misfire rate is counted per cylinder over rolling windows and compared against two thresholds: a catalyst-damaging rate (triggers flashing MIL) and an emissions-exceeding rate (triggers solid MIL). The PCM logs which cylinder is misfiring based on crankshaft position at the time of each detected event. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
Code P0382 allows for cautious short-distance driving, but the underlying cause — most likely failed glow plugs on bank 2 — will worsen with time. Fuel economy suffers, and ignoring the fault for weeks can turn a $100 fix into a much larger repair bill.
Mechanic's Pro Tip
Before replacing any component on P0382, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Glow plugs and labor: $150 - $400