P0670 OBD-II Trouble Code: Glow Plug Module Control Circuit

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0670 code

P0670 is a diagnostic trouble code (DTC) for "Glow Plug Module Control Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0670 DIAGNOSTIC Get a fair and transparent estimate upfront

P0670 code definition

If your vehicle’s ECM detects a problem with the Glow Plug Control Module (GPCM) control circuit, this code gets stored.

What the P0670 code means

Unlike gas engines, diesel engines don’t use sparkplugs for ignition. Instead, they rely on glow plugs for this important task. As the name would suggest, the Glow Plug Control Module is a big part of this. If it isn’t working correctly, your engine may not start.

What causes the P0670 code?

One problem could simply be the GPCM itself. A defective GPCM will set off this code all on its own. Other common issues that lead to a P0670 code are:

  • GPCM harness that’s shorted or open
  • GPCM circuit that’s suffering from a poor electrical connection
  • The ECM isn’t working correctly (this is pretty rare)

What are the symptoms of the P0670 code?

The most obvious problem related to this code is that your diesel engine simply won’t start. At the very least, it will most likely hesitate before coming to life. Usually, if the weather is warm, even a P0670 code shouldn’t stop your vehicle from starting. However, if it’s cold out, you’ll probably have a lot more trouble getting going.

Even if the engine does start, you will most likely hear a very loud knocking noise coming from it. This will continue until the engine warms and is able to function normally within an acceptable operating temperature.

White smoke may also come out of your vehicle’s exhaust. This is because the hard start produces excess fuel that must be burned off. The engine will have a noticeable miss before the cylinder head temperature increases enough to sustain total combustion.

How does a mechanic diagnose the P0670 code?

First, your mechanic will use their OBD-II scanner to diagnose which codes have been stored. Then, they’re going to check to see if your battery is working. Next, they’ll inspect the wiring, looking for any defects that may lead to the GPMC not getting the power it needs to work properly. A voltmeter helps with this.

After all that, they’re going to check to see if the ignition switch delivers power. They’ll do the same with the relay actuation by unplugging the oil temperature sensor and then hitting the ignition.

Common mistakes when diagnosing the P0670 code

The biggest mistake mechanics make when this code is present is going right to replacing the glow plug. As it’s the most obvious feature of the problem, many people assume it’s simply not working. Although a brand new glow plug may function better at first, if you don’t address the underlying problems, it will only be a matter of time before you need to see a mechanic again.

How serious is the P0670 code?

Your life won’t be in danger when the P0670 code is stored. Likewise, it’s not going to lead to any serious damage to your vehicle. However, until this problem is fixed, you are in for a terrible time with your ignition. So, in that regard, this is a very serious issue that should be addressed right away.

What repairs can fix the P0670 code?

Your mechanic may do any of the following:

Additional comments for consideration regarding the P0670 code

Just because your diesel engine needs a couple extra seconds to start in the cold doesn’t mean your GPMC or glow plug need to be replaced or repaired.

Need help with a P0670 code?

At YourMechanic, we have an army of certified mobile mechanics ready to rescue you from the P0670 code and all kinds of other problems that can impact your vehicle. All you have to do is fill out this online form and we’ll quickly reply with a quote before scheduling an appointment. You can also call 1-800-701-6230 to speak with a service advisor about a good time and date for repairs. Our mechanics will happily meet you at your home or workplace.

trouble codes
P0670
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0670 code.

SCHEDULE P0670 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,361

Rating Summary
4,946
200
50
30
135
4,946
200
50
30
135

William

16 years of experience
64 reviews
William
16 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Denver, Colorado
Couldn’t be happier with my experience with William. Will happily recommend him to everyone and will definitely be using him again. Fantastic service.

Andrian

31 years of experience
112 reviews
Andrian
31 years of experience
BMW 525i - Check Engine Light is on - Fort Lauderdale, Florida
Highly recommend Adrian for all automotive services. Very professional and extremely knowledgeable about everything related to our car. He explained everything so we knew exactly what was needed and went above and beyond to make the process easy. I would never use another person to work on our cars. EXCELLENT OVERALL!!

Brian

22 years of experience
335 reviews
Brian
22 years of experience
Chevrolet Colorado - Check Engine Light is on - Orange Park, Florida
Brian is a very experienced mechanic. Billing not so sharp. Wrong time (corona-19).to be stiff with adding up, Informing the older customers what to expect? Very sorry to say goodbye to a great mechanic!

Scott

35 years of experience
665 reviews
Scott
35 years of experience
Dodge Grand Caravan - Check Engine Light is on - Phoenix, Arizona
This is the second time I have used his service. All I can say. if he can find my mistakes, he can fix anything. Thanks once again.


More related articles

5 Essential Things to Know About Your Car’s Dashboard
The The dashboard in your car is the control panel of your vehicle. It provides you with all the information you need to know, as well as houses the instruments and controls for operating the vehicle properly. The dashboard provides...
P0468 OBD-II Trouble Code: EVAP Control System Malfunction
P0468 P0468 code definition The P0468 code is defined as Purge Flow Sensor Circuit High Input. Co-existing OBD-II codes may include P0440 or P0442, often indicating a loose gas cap, or P0443 through P0449, which can indicate an EVAP Purge...
Symptoms of a Bad or Failing Distributor Rotor and Cap
Common signs include engine misfires, car not starting, the Check Engine Light coming on, and excessive or unusual engine noises.

Related questions

Code p0037: Bank 1, Sensor 2 H02S Heater Control circuit signal had low voltage for a pre-determined period of time

Hello. If your oxygen sensor is reading low then it may be possible that it needs to be replaced. If there was a blown fuse or disconnected wire then there would be no signal at all. If the oxygen sensor...

Dash lights flashing on while driving

Hello, thank you for writing in. Electrical issues can be incredibly difficult to diagnose. Typically when every dash light turns on, there is an issue with the main power supply. This means an issue with the battery, alternator, wiring, or...

Hello, I have a 2010 Dodge Avenger Sxt Automatic 2.4l. the lightning bolt light is flashing in morning when turn heat on immediate

You will need to have computer scanned to see if codes are stored and have them diagnosed. The throttle body light comes on and flashes when the system detects a problem and goes into failure mode and should store a...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com