Dealing with the P0674 code can be annoying, but you can fix it quickly if you follow the right steps.
First, confirm the error code using an OBD-II scanner.
Next, use a multimeter to check your glow plugs and replace any that are bad.
Also, look at the wiring harness and connectors for any damage or rust; make sure all connections are clean and tight.
Finally, check that the glow plug control module is getting the right voltage.
By doing these steps promptly, you can get your engine running smoothly again and avoid more problems.
Want to know what usually causes this issue and the symptoms to watch for?
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Key Takeaways
- Replace any bad glow plugs to make sure the engine starts properly.
- Look for and fix any damaged or corroded wires and connectors.
- Check the glow plug control module to see if it’s giving the right voltage.
- Use a multimeter to check the resistance of each glow plug.
Understanding the P0674 Code
The P0674 code means there’s a problem with the glow plug control circuit, which is crucial for starting and running diesel engines. If you see this code, it indicates an issue affecting how well your diesel engine performs.
It’s important to keep your glow plugs in good shape, as bad ones can make it hard to start your engine, especially in cold weather. Regularly check your glow plugs and control module to make sure they’re working properly.
Also, look for damaged wiring or rusty connections, as these can cause the code to appear. By taking care of your glow plugs and fixing issues quickly, you’ll avoid more serious engine problems and keep your diesel engine running smoothly.
Ignoring this code can lead to major damage and expensive repairs, so don’t delay.
Symptoms of P0674
When the P0674 code shows up, it means there’s a problem with the glow plug control circuit.
You’ll notice a few telltale signs. First, your car might be hard to start, especially on cold mornings, because the glow plugs aren’t working right. Your diesel engine may also run roughly, causing vibrations and inconsistent performance.
You might see an increase in emissions, as the engine isn’t burning fuel properly. The check engine light will come on, indicating you need to check your diesel engine soon.
It’s important to fix these issues quickly to avoid further damage. Regularly check and maintain your glow plug system to ensure your engine runs smoothly and to avoid expensive repairs.
Pay attention to these signs to keep your vehicle in good shape.
Common Causes of P0674
Understanding the common reasons for the P0674 code can help you fix the problem and avoid more engine issues.
Start by checking the glow plugs—bad glow plugs can cause misfires and make it hard to start the engine, especially in cold weather. Use a multimeter to regularly check each glow plug’s resistance.
Next, take a good look at the wiring. Broken or rusty wires and connectors can mess up the glow plug circuit and cause the P0674 code. Make sure all electrical connections are clean and in good shape.
Problems with the control module can also trigger this code, so keep an eye on the ECM for any software issues or malfunctions.
Lastly, remember that extreme temperatures can affect how well the glow plug system works.
Faulty Glow Plug
When your engine has a hard time starting, especially in cold weather, it might be because of a bad glow plug. Glow plugs help heat the engine in diesel cars.
Over time, they can wear out and stop working, making it tough to start the car, increasing emissions, and causing rough idling. It’s important to check and maintain glow plugs regularly.
You can test them with a multimeter to see if they’re working. If one is bad, you should replace it. It’s usually a good idea to replace all the glow plugs at the same time to keep things running smoothly.
Replacing glow plugs on time helps keep your engine efficient and reliable in all weather.
Wiring Issues
When you’re dealing with the P0674 code, it’s important to check the wiring for any damage or rust that could mess up the glow plug control circuit.
Start by looking at the wiring harness and connectors for any scratches, cuts, or exposed wires. Rusty connections can really mess with the electrical flow, causing problems with the glow plug system.
Use a multimeter to check for continuity and find any breaks in the circuit. If you find any damage, fix the wiring by replacing the bad sections or connectors.
Make sure all connections are clean and tight to get everything working right again. Fixing wiring issues properly can help you quickly solve the P0674 code and avoid more engine problems.
Control Module Problems
Issues with the glow plug control module can cause the P0674 code to show up, leading to hard starts and other engine performance problems. If the control module isn’t working right, it mightn’t manage the glow plugs correctly, affecting their heating cycles.
It’s important to run diagnostics on the control module to spot any voltage issues or software problems. If the diagnostics show the control module is faulty, you might need to replace it.
It’s also a good idea to consider replacing the glow plugs at the same time to ensure everything works well together. This can help prevent future problems and keep your engine running smoothly.
Addressing control module issues quickly ensures your diesel engine stays reliable and avoids major damage.
Diagnosing P0674
To accurately diagnose the P0674 code, start by using an OBD-II scanner to confirm the specific error and check for any related trouble codes.
Use diagnostic tools to inspect the glow plugs and check their resistance with a multimeter. Faulty glow plugs will show higher resistance.
Next, look over the wiring for any damage or corrosion that could affect connectivity. Use troubleshooting techniques like checking the control module and measuring its voltage output; any differences here can indicate problems.
Also, make sure the relay is working properly and visually inspect the ECM (Engine Control Module) for any signs of damage.
Thoroughly checking all these potential issues will help you pinpoint the exact cause of the P0674 code efficiently.
Affected Vehicle Models
Many diesel-powered vehicles, like the Chevy Silverado, GMC Sierra, Volkswagen Golf TDI, and Mercedes-Benz Sprinter, can get the P0674 code because of problems with their glow plug systems.
For example, the Chevy Silverado often has wiring that rubs against the engine block, which can cause this error code. Similarly, the Volkswagen Golf TDI depends a lot on its glow plugs for starting, and any issue with them can lead to the P0674 code.
The GMC Sierra is similar to the Silverado, so it also has wiring problems. Lastly, the Mercedes-Benz Sprinter, a commercial van, can have glow plug issues too.
Knowing these common problems can help you find and fix the P0674 code more easily.
Fixing the P0674 Code
Fixing the P0674 code involves a step-by-step approach.
First, replace any bad glow plugs and check the glow plug control module.
If your OBD-II scanner shows the P0674 code, start by swapping out the faulty glow plug.
Use a multimeter to measure the resistance of each glow plug and replace any that have unusual readings.
Then, check the glow plug control module to make sure it’s giving the right voltage.
Look over the wiring for any signs of corrosion or damage and make sure all connections are tight.
If you find any wiring problems, fix or replace those sections.
Preventing P0674
Preventing the P0674 code means taking care of your glow plug system with regular check-ups and maintenance. This helps you avoid expensive fixes and keeps your vehicle running well.
Here are some simple steps to follow:
- Check Glow Plugs Regularly: Use a multimeter to check the glow plugs’ resistance and make sure they’re working right.
- Look at Wiring and Connections: Inspect the wiring and connectors for any damage or rust to ensure they work properly.
More OBD-II Codes
Frequently Asked Questions
Can Driving With the P0674 Code Damage My Engine?
Driving with the P0674 code can harm your engine. This code means your engine isn’t running well and is polluting more. It’s important to check for bad glow plugs or wiring issues to avoid serious engine damage and expensive repairs.
How Long Does It Take to Fix the P0674 Code?
Fixing the P0674 code can take anywhere from 1 to 3 hours. This depends on following the troubleshooting steps, like checking the glow plugs and wiring, and making sure you do thorough diagnostics for accurate results.
What Tools Are Needed to Diagnose the P0674 Code?
You’ll need some basic tools to figure out what’s causing the P0674 code. First, get an OBD-II code reader to identify the code. Then, use a multimeter to check the glow plugs and their wiring. A voltage tester will also help you see if the glow plug control module is working properly.
Can the P0674 Code Cause My Vehicle to Fail Emissions Tests?
Yes, the P0674 code can cause your vehicle to fail emissions tests. Emissions rules are strict, and the issues related to the P0674 code, like increased emissions and rough idling, can directly affect how your vehicle performs on these tests.
Is It Safe to Drive With the Check Engine Light on Due to P0674?
Driving with the check engine light on because of P0674 is like ignoring a serious problem; it’s not safe. You might have trouble starting the car and notice it running rough. Fix the issue quickly to avoid major engine damage.
Conclusion
If you get a P0674 code, it’s important to fix it quickly to keep your engine running smoothly and avoid expensive repairs.
First, use an OBD-II scanner to confirm the error.
Then, test and replace any faulty glow plugs, check the wiring and connectors, and inspect the glow plug control module.
Keeping these parts in good shape can help prevent problems down the road.
Acting fast not only improves your vehicle’s performance but also helps it last longer.
Keep your car in great condition by addressing P0674 right away.
