U0106 code meaning
Lost Communication With Glow Plug Control Module 1
Network system Generic code U01xx codes Check engine light
What U0106 means
U0106 reports that glow plug control module 1 of a diesel engine no longer communicates. In Ford's 2023 diesel summary (6.7 L and 3.0 L) the GPCM is declared lost after 5 s of silence. GM's 2015 Cruze diesel table fails it when no GPCM message arrives for 0.25 s over a 10 s test (Type B); GM's 2018 diesel table also lets the GPCM report that it misses ECM frames $C9, $4C1 or $4F1 and sets U0106 after 11 s as Type B over two trips. Isuzu's N-Series bulletin SB18-N-001A (4HK1, 2011–2018) links the MIL with U0106 to water running down the glow plug harness into the GPCM plug; sealed terminals fix it. Expect hard cold starts, white smoke and an unreliable wait-to-start lamp.
U0106 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0106
- MIL on
- Long cranking or no start when cold
- White smoke after cold start
- Wait-to-start lamp behaves oddly
Common causes of U0106
- Most likelyWater or corrosion in the glow plug module connector or harness
- PossibleModule supply fuse, relay or ground faulty
- PossibleDamaged CAN lines to the glow plug module
- Less likelyGlow plug module internally faulty (overtemperature, driver)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Glow plug control moduleCAN bus wiring
What each part of U0106 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 06 | The exact fault in that area. |
What to do next
- Note U0106 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0106
What does U0106 mean?
U0106 means "Lost Communication With Glow Plug Control Module 1". U0106 reports that glow plug control module 1 of a diesel engine no longer communicates. It is a generic code, so it means the same on every make.
Is it safe to drive with U0106?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0106 fail an emissions test?
Yes, it can. U0106 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0106 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U0106 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.