P0384 Glow Plug Heater Circuit B

Definition: The OBD-II code P0384 indicates a malfunction in the glow plug heater circuit “B”. This typically refers to an issue with the electrical circuit responsible for heating the glow plugs, which are used to start diesel engines in cold conditions.

p0384 – Glow Plug Heater Circuit B

Typical severity: Moderate

Common Causes

P0384 – Glow Plug Heater Circuit B

Description: The PCM has detected a problem in the glow plug heater circuit B.

Common Causes:

• Faulty glow plug
• Defective glow plug relay
• Wiring issues in the glow plug circuit
• Corroded or loose connections in the circuit
• PCM software needs to be updated

Common Misdiagnosis

OBD2 Code: P0384

Description: Glow Plug/Heater Circuit “B” Malfunction

Common Misdiagnosis: Replacing the glow plugs without checking the relay or control module, assuming a wiring issue without inspecting connectors and harnesses, or replacing components without verifying the battery voltage and charging system.

Common Diagnostic Steps

OBD2 Code: P0384

Description: Glow Plug Heater Circuit B

Common Diagnostic Steps:

• Check the glow plug relay for proper operation and replace if necessary.
• Inspect the wiring and connectors in the glow plug circuit for signs of damage, corrosion, or disconnection.
• Test each glow plug for continuity to ensure they are functioning correctly; replace any faulty glow plugs.
• Verify that the power supply to the glow plug system is within specifications using a multimeter.
• Examine the engine control module (ECM) for any additional fault codes that might indicate related issues.
• If equipped, check the fuse associated with the glow plug circuit and replace it if blown.