P0681 Fault Code

Cylinder 11 Glow Plug Circuit

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0681 fault code indicates a problem with the glow plug circuit for cylinder 11 in diesel engines. Glow plugs are essential for starting diesel engines, as they help to preheat air in the combustion chamber, enabling the fuel to ignite more efficiently. When there's an issue with the glow plug circuit of cylinder 11, it can lead to poor engine performance, increased emissions, and difficulty in starting the engine, especially in cold weather.

• Symptoms of this fault code include hard starting, rough idling, and decreased fuel economy.
• Diagnostic trouble codes (DTCs) related to the glow plugs may also be present, which can help pinpoint the issue.

What are the symptoms of the P0681 code?

Common symptoms associated with the P0681 fault code include:

• Difficulty starting the engine, particularly in lower temperatures.
• Rough or uneven engine idling after starting.
• Increased smoke emissions during engine operation.
• Lower fuel efficiency due to improper combustion caused by the faulty glow plug.
• Activation of the check engine light, indicating that a diagnostic trouble code has been triggered.

What causes the P0681 code?

Several factors can lead to a P0681 error code. The main causes include:

• A faulty glow plug for cylinder 11 that has either burned out or malfunctioned.
• Wiring issues such as frayed, short-circuited, or corroded wires within the glow plug circuit, leading to poor electrical connections.
• Failed engine control module (ECM) that may not be providing proper signals to the glow plug.
• Faulty relays or fuse issues that disrupt the power supply to the glow plug circuit.

How to fix P0681?

To resolve the P0681 fault code, follow these steps:

• Begin by visually inspecting the glow plug for cylinder 11 and its circuit for any visible signs of damage, corrosion, or disconnection.
• Test the glow plug for continuity and replace it if it's found to be faulty.
• Check the wiring and connectors related to the glow plug circuit for damage or poor connections and repair or replace as necessary.
• Inspect the related fuses and relays, replacing any that are blown or malfunctioning.
• Use a diagnostic scanner to erase the codes and perform a test drive to ensure that the issue is resolved and that the check engine light does not reappear.