U0407
Invalid Data Received From Glow Plug Control Module 1
Communication network (diesel glow plug)
Generic OBD-II
Medium
What it means
U0407 sets when a control module reads data from the glow-plug control module — the diesel cold-start heater system — that is missing or implausible. Glow plugs help a cold diesel start and run smoothly during warm-up, so the main effect is hard cold starting and rough running when cold, not a loss of power on a warmed-up engine.
Medium
Can I keep driving? Usually drivable — expect hard cold starts and rough running until warm, but no loss of power once the engine is up to temperature.
Common symptoms
What you'll notice
- Check-engine light and/or glow-plug warning light on
- Hard starting when the engine is cold
- Rough running, misfire feel, or white smoke during cold warm-up
- Starts and runs normally once warm
Common causes
Most likely first
- Faulty glow-plug control module or its power/ground supplyLikely
- Corroded or loose connectors and data-bus wiring to the moduleCommon
- Low or unstable battery voltageCommon
- Software incompatibility after a module was replaced or updatedLess often
- An underlying glow-plug circuit fault reported by the moduleLess often
How to diagnose & fix
Work through it in order
- Scan all modules and record stored codes and freeze-frame data before clearing.
- Check battery and charging voltage — low voltage is a common cause of glow-plug and bus faults.
- Inspect connectors and wiring to the glow-plug control module and along the data bus.
- If the module or ECM was recently replaced or flashed, confirm the software is compatible.
- Run the manufacturer's pinpoint tests on the glow-plug module and its circuit; replace only if confirmed.
FAQ
Quick answers
Is it safe to drive with U0407?+
Generally yes — the main effect is harder cold starting and rough warm-up, not a loss of power. It's a diesel cold-start system, so get it fixed before cold weather.
Can I just clear U0407?+
You can, but if the glow-plug module or its data link is still faulty the code will come back, usually noticeable on the next cold start.
Related codes
Often seen with U0407
Read & clear U0407 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX