P0670
Glow Plug Module Control Circuit
Encountering the engine check light code P0670 signifies an explicit mechanical or electrical operational breakdown categorized as "Glow Plug Module Control Circuit". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
The diagnostic trouble code P0670 indicates an active fault in the glow plug module control circuit circuit or component. The most common signs are hard starting in cold weather, check engine light on, white smoke on startup. You can typically drive short distances, but ignoring this code long-term will cause accelerated component wear and higher repair costs.
Symptoms
Hard starting in cold weather, check engine light on, white smoke on startup
Common Causes
- Failed glow plug control module
- Open or shorted control circuit wiring
- Blown glow plug module fuse
- Corroded ground connection
How to Fix
- 1 Test and replace glow plug control module
- 2 Repair damaged wiring harness
- 3 Replace blown fuses
- 4 Clean main ground cables
Technical Explanation
P0670 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The PCM distinguishes between electrical faults (circuit codes) and performance faults (rationality codes) by comparing the sensor's reported value against what other sensors would predict under the same engine operating conditions. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
You can drive short distances, but the symptoms — hard starting in cold weather, check engine light on, white smoke on startup — indicate the affected system is compromised. Leaving this unresolved will lead to progressively worse fuel economy and potential damage to components beyond the original fault.
Mechanic's Pro Tip
Before replacing any component on P0670, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Related Fault Codes
Frequently Asked Questions
What does OBD2 code P0670 mean?
OBD2 code P0670 refers to Glow Plug Module Control Circuit. Encountering the engine check light code P0670 signifies an explicit mechanical or electrical operational breakdown categorized as "Glow Plug Module Control Circuit". Professional scanner tools usually flag this subsystem loop early on.
What are the most common symptoms of DTC P0670?
Drivers experiencing code P0670 typically report: Hard starting in cold weather, check engine light on, white smoke on startup.
Is it safe to drive with trouble code P0670 active?
You can drive short distances, but the symptoms — hard starting in cold weather, check engine light on, white smoke on startup — indicate the affected system is compromised. Leaving this unresolved will lead to progressively worse fuel economy and potential damage to components beyond the original fault.
How much does it cost to fix code P0670?
The estimated repair cost for P0670 ranges from $150 to $500 USD. Glow plug module: $200 - $500
Glow plug module: $200 - $500
Need Professional Diagnostic Assistance?
Always verify sensor signals and wiring integrity with an OBD2 scanner before purchasing replacement parts.
Explore All Powertrain Codes →