AutoFixDB - Free OBD-II diagnostic trouble code lookup. Find causes, symptoms, diagnostic steps and repair solutions.

Overview

P0382 indicates a malfunction in the diesel engine glow plug or heater circuit B detected by the powertrain control module.

Common Symptoms

Hard or prolonged engine starting, particularly in cold temperatures
Illuminated check engine or glow plug warning light
Rough idling until engine reaches operating temperature

Most Common Causes

Open or high resistance in glow plug circuit B wiring high

Damaged, corroded harness or loose connectors raising resistance beyond acceptable range

Failed glow plug heater element(s) high

Internal breakage or burnout leads to open-circuit reading

Faulty glow plug relay or control module medium

Relay or module driving the circuit may fail or not supply correct voltage

Blown fuse in glow plug circuit medium

Fuse protecting the circuit may interrupt power flow

PCM/ECM driver circuit internal failure low

Less common but possible; PCM may falsely detect circuit fault due to internal driver issues

Diagnostic Steps

Retrieve and confirm P0382 code with an OBD-II scanner

Expected: P0382 appears stored in PCM memory

Interpretation: Confirms circuit B fault present
Visually inspect glow plug wiring harness, connectors, and related fuses

Expected: No corrosion, broken wires, or loose connections

Interpretation: Issues here may indicate wiring repair needed
Measure resistance of glow plug heater elements in circuit B using multimeter

Expected: Resistance within manufacturer specification (low ohms)

Interpretation: Open or high resistance indicates faulty glow plug
Test voltage supply to glow plug circuit with ignition on

Expected: Battery voltage present at connector

Interpretation: No voltage suggests fuse, relay, or wiring issue
Test glow plug relay/module operation and output under command

Expected: Proper switching and voltage output

Interpretation: Failure here suggests relay or control module replacement

Repair Solutions

Repair or replace damaged wiring harness/connectors medium

Estimated Cost: $80 - $250

Costs vary by vehicle model and extent of wiring work

Replace faulty glow plug heater element(s) medium

Estimated Cost: $150 - $500

Depends on number of plugs and labor involved

Replace glow plug relay or control module medium

Estimated Cost: $100 - $400

Relay normally cheaper; module replacement can be more complex

Replace blown fuse and correct underlying cause easy

Estimated Cost: $5 - $50

Investigate cause to avoid repeat blow

Common Misdiagnoses

Avoid these common diagnostic mistakes:

Misinterpreting weak battery voltage as glow plug circuit fault

Frequently Asked Questions

Technical definition of P0382 OBD-II Code

The P0382 code stands for Glow Plug/Heater Circuit B Malfunction. This generally indicates an issue with the Ignition system.

Can P0382 cause engine damage?

This is a medium priority issue. Difficulty starting especially in cold weather, prolonged cranking, rough idle until engine warms

How do I know if I have code P0382?

You may experience the following: Hard or prolonged engine starting, particularly in cold temperatures, Illuminated check engine or glow plug warning light, Rough idling until engine reaches operating temperature.

What parts fail when P0382 is set?

It can be caused by several factors, most notably: Open or high resistance in glow plug circuit B wiring, Failed glow plug heater element(s), Faulty glow plug relay or control module.

Repair cost breakdown for P0382

The cost varies significantly based on the root cause. For example, replacing a Replace blown fuse and correct underlying cause typically costs between $5 and $50, while fixing a Replace faulty glow plug heater element(s) can range from $150 to $500.

Does P0382 affect Ford, Toyota, or Honda?

This is a universal code. You might see P0382 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

P0382: Glow Plug/Heater Circuit B Malfunction