Error Code P0678: What It Means & What To Do?

<<See All OBD Codes

Oftentimes, Engine Warning Light turns up almost immediately it senses the OBD code error. This directly impacts the engine performance as it struggles with power and acceleration as well as failed ignition system causing increased consumption of fuel by the engine along with engine stalling and not starting.

The P0678 code detects an error with the glow plug circuit in cylinder 8.

The code P0678 tells you that something in the glow plug circuit is faulty causing the glow plug on cylinder 8 to fail to heat up. The entire circuit must be checked to locate the fault.

This code relates to the device diesels use to heat the cylinder head for a few seconds when attempting to start a cold engine called a glow plug. A diesel relies entirely on the momentary high level of heat through compression to spontaneously ignite the fuel. The glow plugs in the cylinder 8 has failed.

What causes this problem with the Cylinder 8 Glow Plug Circuit?

• Defective/faulty glow plugs
• Defective/faulty glow plug relays
• Malfunctioning glow plug timer or glow plug module
• Glow plug circuit fuses blown
• Issues with the electrical components in the glow plug circuit, such as open or short wires, or corroded, loose, or damaged connectors

1. Glow Plug - Check for cylinder 8 glow plug error and replace it faulty parts now! Buy new glow plug from us.
2. Glow Plug Connector - Check for connector problems and replace it as required. Buy new glow plug connector now!
3. Glow Plug Relay - Damaged relays will lead to ignition problems and lead to hard starting and stalling. Buy new relay now!
4. Starter Relay - Starter relay must also be inspected for failure and replace it, if faulty. Buy new starter relay now.
5. Engine Wiring Connector - Engine wiring connectors might also be at fault and need early replacement for solving OBD code P0678 error. Buy new components now!
6. Engine Control Module - OBD Error Code P0678 can simply be due to faulty ECM. Replace old and damage components now!
7. Powertrain Control Module - P0678 error code also relates to problems with the powertrain control module. Find all the Powertrain related parts with us.

Interested in knowing the symptoms to OBD code P0678? If yes, then you have arrived at the right place. We at Parts Avatar have listed out few common symptoms associated with this fuel injector problem.

Common Symptoms

• PCM storing and flashing OBD code P0678
• Hard starting and stalling
• Lack of engine power and response
• Engine may hesitate when accelerating

Here are some ways with the help of which you will be able to correct the OBD Code P0678.

• Glow Plug Replacement
• Glow Plug Relay/ Starter Relay Replacement
• Faulty Wiring and Connector Replacement
• Faulty Starter Replacement

There is no need to be anxious as Parts Avatar – Car Parts Online is here to help you out! We have high grade Glow Plug Relay, Glow Plug Timer, Electrical Component, Glow Plug Circuit, PCM, Engine, Starter Relay and a lot more for our precious customers.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P0678 code to be stored:

• To diagnose this code, start by using a DVOM (digital volt-ohmmeter). Disconnect the glow plug connector, set the DVOM on ohms and place the red lead on the terminal of the glow plug and at the back end of a good ground.
• The range should be between 0.5 to 2.0 ohms. Verify the measurements from the factory service manual. If the range is outside the specifications, then the glow plug must be replaced.
• Next, check the resistance in glow plug wire to the glow plug relay buss bar on the valve cover. Notice how the relay (which looks like a starter relay) has large gauge wire that leads to a buss bar where all the wires of the glow plugs are attached.
• Next, test the wire to the cylinder 2 glow plug by replacing the red lead on the buss bar wire and the black lead to the glow plug inside. Once again, the range must be 0.5 to 2.0 ohms (with 2 ohms being the highest resistance).
• If the resistance is higher, then the wires from the buss bar to the glow plug must be replaced. Make sure to reconnect wires, as this may cause the buss bar to splurge.
• Then, technicians look for signs of cracks, looseness, or missing insulation. Lastly, connect the code scanner to the OBD port on the vehicle (usually located under the dash), turn the key at “on” with the engine off. Then clear the codes and test if the vehicle to see if the error code returns again.

Common Mistakes When Diagnosing the P0678 Code

Oftentimes the PCM sensor and circuit is blamed, and replaced, without checking the circuit as well as neglecting the damaged wiring and connectors. Because there can be several causes for this code, a complete inspection should be carried out in order to avoid repairs that may be unnecessary and more expensive.