What it means
ECU lost communication with glow plug control module 2 (second module on engines with bank-individual glow control).
At a glance
- Usually lights the warning light of the system that lost communication
- Affects emissions; the car can fail an emissions test
How it works
Glow Plug Control Module 2 controls the glow plugs assigned to the second independently controlled group on equipped diesel engines. U019C sets when expected network messages from this second module are missing, which can leave its glow-plug functions unavailable even if another glow-plug module still communicates.
Common causes
Most likely first.
- Module unpowered
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Glow plug system warning or message
- Glow plug functions may be unavailable or impaired
- Other communication codes
How to diagnose it
- Save freeze-frame data and scan the engine and network modules for glow-plug and communication codes, checking whether faults specifically identify module 2.
- Note whether cold starting is difficult or a glow-plug warning appears, and compare module 2 status with the other glow-plug control module in scan data if available.
- Inspect module 2's power, ground, connector, and harness for loose pins, corrosion, heat damage, or chafing.
- Check the network wiring to module 2 and look for gateway communication faults that affect that module's messages.
- Test the communication bus and terminating resistance against the manufacturer's specification if the wiring and supply checks pass.
Common fixes
- Repair a damaged, loose, or corroded connector or harness at glow plug control module 2.
- Restore module 2's power or ground supply and repair the cause of a blown fuse.
- Correct a gateway routing fault affecting module 2.
- Repair the network or replace a failed module 2 or out-of-spec terminating resistor after confirming the fault.
Can I keep driving?
The engine may be harder to start when cold and may run less cleanly until the second glow-plug group works. Avoid repeated long cranking, and address the fault promptly if starting becomes unreliable or an emissions warning remains on.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.