What it means
A control module is not receiving expected messages from the Engine Coolant Pump Control Module. The resulting effect depends on the vehicle's cooling system and control strategy.
At a glance
- Usually lights the warning light of the system that lost communication
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The Engine Coolant Pump Control Module manages or reports operation of the engine coolant pump. U019F sets when a control module stops receiving expected messages from it, which can prevent the vehicle from confirming or controlling coolant circulation.
Common causes
Most likely first.
- Module unpowered
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Cooling-system warning or message
- Engine temperature may rise if coolant circulation is affected
- Other communication codes
How to diagnose it
- Save freeze-frame data and scan the engine and network modules for coolant-pump, temperature, and communication codes.
- Check the coolant temperature reading and any cooling-system warning, and look for signs of overheating without opening a hot cooling system.
- Inspect the pump control module's power, ground, connectors, and wiring for corrosion, damage, or a loose connection.
- Check the communication wiring to the pump module and look for gateway faults that could interrupt its messages.
- If supply and wiring appear sound, have the network and terminating resistance tested against the manufacturer's specification.
Common fixes
- Repair damaged wiring or a loose or corroded connector at the pump control module.
- Restore the module's power or ground supply and correct the cause of any blown fuse.
- Correct a gateway routing fault affecting the pump module.
- Repair the communication network or replace a confirmed failed module or out-of-spec terminating resistor.
Can I keep driving?
Stop driving if the temperature rises, an overheating warning appears, or coolant circulation seems impaired; continued operation can cause severe engine damage. If there are no temperature symptoms, drive only as needed to reach a safe place for prompt diagnosis and watch the temperature closely.
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.