What are the common causes of P0670?

An open in the glow plug module control wire. A blown fuse feeding the glow plug module. Corrosion at the glow plug module connector. A failed glow plug control module. A faulty ECM command to the module.

Check the glow plug module fuse. Measure the control voltage at the glow plug module. Inspect the module connector and control wire. Test the module command from the ECM. Repair the open if the control wire has no power. Clear the code and retest.

P0670

Glow Plug Control Module 1 Control Circuit/Open

System: Computer output circuits (P code)
Lamp: Check Engine Light
Category: Powertrain - Computer and Auxiliary Controls

What it means

P0670 means Glow Plug Control Module 1 Control Circuit/Open.

Where it lives

For P0670, the module sits on the circuit this code reports. The description of P0670 reports the module as open.

Check these first

An open in the glow plug module control wire
A blown fuse feeding the glow plug module
Corrosion at the glow plug module connector
A failed glow plug control module
A faulty ECM command to the module

What to do next

Check the glow plug module fuse
Measure the control voltage at the glow plug module
Inspect the module connector and control wire
Test the module command from the ECM
Repair the open if the control wire has no power
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.